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Sample records for cortical bone thickness

  1. Buccal cortical bone thickness on CBCT for mini-implant

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    Goo, Jong Gook; Lim, Sung Hoon; Lee, Byoung Jin; Kim, Jae Duk [School of Dentistry, Chosun University, Gwangju (Korea, Republic of)

    2010-12-15

    Cortical bone thickness is one of the important factor in mini-implant stability. This study was performed to investigate the buccal cortical bone thickness at every interdental area as an aid in planning mini-implant placement. Two-dimensional slices at every interdental area were selected from the cone-beam computed tomography scans of 20 patients in third decade. Buccal cortical bone thickness was measured at 2, 4, and 6 mm levels from the alveolar crest in the interdental bones of posterior regions of both jaws using the plot profile function of Ez3D2009TM (Vatech, Yongin, Korea). The results were analyzed using by Mann-Whitney test. Buccal cortical bone was thicker in the mandible than in the maxilla. The thickness increased with further distance from the alveolar crest in the maxilla and with coming from the posterior to anterior region in the mandible (p?0.01). The maximum CT value showed an increasing tendency with further distance from the alveolar crest and with coming from posterior to anterior region in both jaws. Interdental buccal cortical bone thickness varied in both jaws, however our study showed a distinct tendency. We expect that these results could be helpful for the selection and preparation of mini-implant sites.

  2. Independent measurement of femoral cortical thickness and cortical bone density using clinical CT.

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    Treece, G M; Gee, A H

    2015-02-01

    The local structure of the proximal femoral cortex is of interest since both fracture risk, and the effects of various interventions aimed at reducing that risk, are associated with cortical properties focused in particular regions rather than dispersed over the whole bone. Much of the femoral cortex is less than 3mm thick, appearing so blurred in clinical CT that its actual density is not apparent in the data, and neither thresholding nor full-width half-maximum techniques are capable of determining its width. Our previous work on cortical bone mapping showed how to produce more accurate estimates of cortical thickness by assuming a fixed value of the cortical density for each hip. However, although cortical density varies much less over the proximal femur than thickness, what little variation there is leads to errors in thickness measurement. In this paper, we develop the cortical bone mapping technique by exploiting local estimates of imaging blur to correct the global density estimate, thus providing a local density estimate as well as more accurate estimates of thickness. We also consider measurement of cortical mass surface density and the density of trabecular bone immediately adjacent to the cortex. Performance is assessed with ex vivo clinical QCT scans of proximal femurs, with true values derived from high resolution HRpQCT scans of the same bones. We demonstrate superior estimation of thickness than is possible with alternative techniques (accuracy 0.12 ± 0.39 mm for cortices in the range 1-3mm), and that local cortical density estimation is feasible for densities >800 mg/cm(3).

  3. WNT16 influences bone mineral density, cortical bone thickness, bone strength, and osteoporotic fracture risk.

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    Hou-Feng Zheng

    2012-07-01

    Full Text Available We aimed to identify genetic variants associated with cortical bone thickness (CBT and bone mineral density (BMD by performing two separate genome-wide association study (GWAS meta-analyses for CBT in 3 cohorts comprising 5,878 European subjects and for BMD in 5 cohorts comprising 5,672 individuals. We then assessed selected single-nucleotide polymorphisms (SNPs for osteoporotic fracture in 2,023 cases and 3,740 controls. Association with CBT and forearm BMD was tested for ∼2.5 million SNPs in each cohort separately, and results were meta-analyzed using fixed effect meta-analysis. We identified a missense SNP (Thr>Ile; rs2707466 located in the WNT16 gene (7q31, associated with CBT (effect size of -0.11 standard deviations [SD] per C allele, P = 6.2 × 10(-9. This SNP, as well as another nonsynonymous SNP rs2908004 (Gly>Arg, also had genome-wide significant association with forearm BMD (-0.14 SD per C allele, P = 2.3 × 10(-12, and -0.16 SD per G allele, P = 1.2 × 10(-15, respectively. Four genome-wide significant SNPs arising from BMD meta-analysis were tested for association with forearm fracture. SNP rs7776725 in FAM3C, a gene adjacent to WNT16, was associated with a genome-wide significant increased risk of forearm fracture (OR = 1.33, P = 7.3 × 10(-9, with genome-wide suggestive signals from the two missense variants in WNT16 (rs2908004: OR = 1.22, P = 4.9 × 10(-6 and rs2707466: OR = 1.22, P = 7.2 × 10(-6. We next generated a homozygous mouse with targeted disruption of Wnt16. Female Wnt16(-/- mice had 27% (P<0.001 thinner cortical bones at the femur midshaft, and bone strength measures were reduced between 43%-61% (6.5 × 10(-13bone strength, and risk of fracture.

  4. An Experimental Study of Radiographic Density of Alveolar Bone and Cortical Thickness of Mandible by Osteoporosis

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    Lee, Byeong Do [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Wonkwang University, Iksan (Korea, Republic of)

    2000-12-15

    To evaluate the effect of the systemic osteoporosis on radiographic density of alveolar bone and cortical thickness of mandible. The bone mineral density values of lumbar and femur were measured by dual-energy X-ray absorptiometry and T scores of lumbar, femur were obtained respectively. Radiographic densities of alveolar bones and panorama mandibular index (PMI, represents as cortical thickness) were analysed statistically according to age and T score variavles. The radiographic density of alveolar bone of maxillary molar showed significant difference by age and femur T group. That of mandibular molar showed significant difference between femur T group. Panorama mandibular index showed significant difference between age groups. The radiographic density of alvealar bones was more dependent on age femur T than lumbar T. Cortical thickness of mandible was correlated with increasing age.

  5. Comparative cortical bone thickness between the long bones of humans and five common non-human mammal taxa.

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    Croker, Sarah L; Reed, Warren; Donlon, Denise

    2016-03-01

    The task of identifying fragments of long bone shafts as human or non-human is difficult but necessary, for both forensic and archaeological cases, and a fast simple method is particularly useful. Previous literature suggests there may be differences in the thickness of the cortical bone between these two groups, but this has not been tested thoroughly. The aim of this study was not only to test this suggestion, but also to provide data that could be of practical assistance for future comparisons. The major limb bones (humerus, radius, femur and tibia) of 50 Caucasoid adult skeletons of known age and sex were radiographed, along with corresponding skeletal elements from sheep, pigs, cattle, large dogs and kangaroos. Measurements were taken from the radiographs at five points along the bone shaft, of shaft diameter, cortical bone thickness, and a cortical thickness index (sum of cortices divided by shaft diameter) in both anteroposterior and mediolateral orientations. Each variable for actual cortical bone thickness as well as cortical thickness indices were compared between the human group (split by sex) and each of the non-human groups in turn, using Student's t-tests. Results showed that while significant differences did exist between the human groups and many of the non-human groups, these were not all in the same direction. That is, some variables in the human groups were significantly greater than, and others were significantly less than, the corresponding variable in the non-human groups, depending on the particular non-human group, sex of the human group, or variable under comparison. This was the case for measurements of both actual cortical bone thickness and cortical thickness index. Therefore, for bone shaft fragments for which the skeletal element is unknown, the overlap in cortical bone thickness between different areas of different bones is too great to allow identification using this method alone. However, by providing extensive cortical bone

  6. A Retrospective Study on Indian Population to evaluate Cortical Bone Thickness in Maxilla and Mandible using Computed Tomography Images

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    Jeegar Ketan Vakil

    2014-01-01

    Conclusion: Mini-implants have gained considerable popularity due to their low cost, effectiveness, clinical management and stability. Among the factors related to microimplant stability, bone density and cortical bone thickness appear to be critical for successful placement. This study will provide knowledge of cortical bone thickness in various areas which can guide the clinicians in selecting the placement site.

  7. Effect of Cortical Bone Thickness on Detection of Intraosseous Lesions by Ultrasonography

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    Sadaf Adibi

    2015-01-01

    Full Text Available Background. Usefulness of ultrasound (US in detection of intrabony lesions has been showed. A cortical bone perforation or a very thin and intact cortical bone is prerequisite for this purpose. Objective. The current in vitro study was aimed at measuring the cut-off thickness of the overlying cortical bone which allows ultrasonic assessment of bony defects. Materials and Methods. 20 bovine scapula blocks were obtained. Samples were numbered from 1 to 20. In each sample, 5 artificial lesions were made. The lesions were made in order to increase the overlying bone thickness, from 0.1 mm in the first sample to 2 mm in the last one (with 0.1 mm interval. After that, the samples underwent ultrasound examinations by two practicing radiologists. Results. All five lesions in samples numbered 1 to 11 were detected as hypoechoic area. Cortical bone thickness more than 1.1 mm resulted in a failure in the detection of central lesions. Conclusion. We can conclude that neither bony perforation nor very thin cortical bones are needed to consider US to be an effective imaging technique in the evaluation of bony lesion.

  8. Mandibular Inferior Cortical Bone Thickness on Panoramic Radiographs in Patients using Bisphosphonates

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    Torres, Sandra R.; Chen, Curtis S. K.; Leroux, Brian G.; Lee, Peggy P.; Hollender, Lars G.; Lloid, Michelle; Drew, Shane Patrick; Schubert, Mark M.

    2015-01-01

    Objective To detect dimensional changes in the mandibular cortical bone associated with bisphosphonate (BP) use and to correlate the measurements of the cortical bone with the cumulative dose of BP therapy. Methods Mandibular inferior cortical bone thickness (MICBT) was measured under the mental foramen from panoramic radiographs of subjects using BP with and without bisphosphonate related osteonecrosis of the jaws (BRONJ) and controls. Results The highest mean MICBT was observed in BRONJ subjects 6.81 (± 1.35 mm), when compared to subjects using BP 5.44 (± 1.09 mm) and controls 4.79 (± 0.85 mm; p<0.01). The mean MICBT of BRONJ subjects was significantly higher than that of subjects using BP without BRONJ. There was a correlation between MICBT and cumulative dose of zolendronate. Conclusion The MICBT on panoramic radiograph is a potentially useful tool for the detection of dimensional changes associated with BP therapy. PMID:25864820

  9. Bisphosphonates improve trabecular bone mass and normalize cortical thickness in ovariectomized, osteoblast connexin43 deficient mice.

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    Watkins, Marcus P; Norris, Jin Yi; Grimston, Susan K; Zhang, Xiaowen; Phipps, Roger J; Ebetino, Frank H; Civitelli, Roberto

    2012-10-01

    The gap junction protein, connexin43 (Cx43) controls both bone formation and osteoclastogenesis via osteoblasts and/or osteocytes. Cx43 has also been proposed to mediate an anti-apoptotic effect of bisphosphonates, potent inhibitors of bone resorption. We studied whether bisphosphonates are effective in protecting mice with a conditional Cx43 gene deletion in osteoblasts and osteocytes (cKO) from the consequences of ovariectomy on bone mass and strength. Ovariectomy resulted in rapid loss of trabecular bone followed by a slight recovery in wild type (WT) mice, and a similar degree of trabecular bone loss, albeit slightly delayed, occurred in cKO mice. Treatment with either risedronate (20 μg/kg) or alendronate (40 μg/kg) prevented ovariectomy-induced bone loss in both genotypes. In basal conditions, bones of cKO mice have larger marrow area, higher endocortical osteoclast number, and lower cortical thickness and strength relative to WT. Ovariectomy increased endocortical osteoclast number in WT but not in cKO mice. Both bisphosphonates prevented these increases in WT mice, and normalized endocortical osteoclast number, cortical thickness and bone strength in cKO mice. Thus, lack of osteoblast/osteocyte Cx43 does not alter bisphosphonate action on bone mass and strength in estrogen deficiency. These results support the notion that one of the main functions of Cx43 in cortical bone is to restrain osteoblast and/or osteocytes from inducing osteoclastogenesis at the endocortical surface. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Three-dimensional mapping of cortical bone thickness in subjects with different vertical facial dimensions

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    Mais Medhat Sadek

    2016-10-01

    Full Text Available Abstract Background The purpose of this study was to determine differences in cortical bone thickness among subjects with different vertical facial dimensions using cone beam computed tomography (CBCT. Methods From 114 pre-treatment CBCT scans, 48 scans were selected to be included in the study. CBCT-synthesized lateral cephalograms were used to categorize subjects into three groups based on their vertical skeletal pattern. Cortical bone thickness (CBT at two vertical levels (4 and 7 mm from the alveolar crest were measured in the entire tooth-bearing region in the maxilla and mandible. Results Significant group differences were detected with high-angle subjects having significantly narrower inter-radicular CBT at some sites as compared to average- and low-angle subjects. Conclusions Inter-radicular cortical bone is thinner in high-angle than in average- or low-angle subjects in few selected sites at the vertical height in which mini-implants are commonly inserted for orthodontic anchorage.

  11. Postnatal Changes in Humerus Cortical Bone Thickness Reflect the Development of Metabolic Bone Disease in Preterm Infants

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    Shuko Tokuriki

    2016-01-01

    Full Text Available Objective. To use cortical bone thickness (CBT of the humerus to identify risk factors for the development of metabolic bone disease in preterm infants. Methods. Twenty-seven infants born at <32 weeks of gestational age, with a birth weight of <1,500 g, were enrolled. Humeral CBT was measured from chest radiographs at birth and at 27-28, 31-32, and 36–44 weeks of postmenstrual age (PMA. The risk factors for the development of osteomalacia were statistically analyzed. Results. The humeral CBT at 36–44 weeks of PMA was positively correlated with gestational age and birth weight and negatively correlated with the duration of mechanical ventilation. CBT increased with PMA, except in six very early preterm infants in whom it decreased. Based on logistic regression analysis, gestational age and duration of mechanical ventilation were identified as risk factors for cortical bone thinning. Conclusions. Humeral CBT may serve as a radiologic marker of metabolic bone disease at 36–44 weeks of PMA in preterm infants. Cortical bones of extremely preterm infants are fragile, even when age is corrected for term, and require extreme care to lower the risk of fractures.

  12. Evaluation of cortical bone thickness of mandible with cone beam computed tomography for orthodontic mini implant installation

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    Seyed Hossein Moslemzade

    2014-07-01

    Full Text Available Background: Achieving maximum anchorage without movement of the teeth in anchorage unit has been a great challenge in orthodontics and the success of the treatment plan highly depends on it. In this case, using orthodontic mini-implants can make a huge difference. The objective of this retrospective study was to measure thickness of cortical bone at prospective mini-implant placement sites in mandible in order to understand stability aspects of mini-implant placement by using cone-beam computed tomography (CBCT images. Materials and Methods: Initial 3-dimensional images of 40 adult patients were studied. The cortical bone thickness was obtained at the alveolar processes from canine to second molar at 5 different vertical levels from the cementoenamel junction (CEJ. To determine the cortical bone thickness, tangent lines were drawn buccolingually to the roots in axial section and a third line was drawn from the middle of these two lines, and the cortical bone thickness was measured where the third line crossed the buccal cortex.   Results: Mandibular and buccal cortical bone thicknesses were 0.79 to 2.49 mm, respectively. There was a statistically significant increase from the CEJ to the apex (P<0.001, while this increase was not statically significant at interdental area of teeth #3 and #4. Comparing the 4 mm section in all sites showed significant increase from anterior to posterior. Conclusion: Based on our results, the cortical bone thickness mostly follows a pattern and depends on the interradicular site rather than individual differences.     Key words: Cone-beam computed tomography; orthodontic anchorage procedures

  13. Comparison of interradicular distances and cortical bone thickness in Thai patients with class I and class II skeletal patterns using cone-beam computed tomography

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    Khumsarn, Nattida [Dental Division of Lamphun Hospital, Lamphun (Thailand); Patanaporn, Virush; Janhom, Apirum; Jotikasthira, Dhirawat [Faculty of Dentistry, Chiang Mai University, Chiang Mai (Thailand)

    2016-06-15

    This study evaluated and compared interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns, using cone-beam computed tomography (CBCT). Pretreatment CBCT images of 24 Thai orthodontic patients with Class I and Class II skeletal patterns were included in the study. Three measurements were chosen for investigation: the mesiodistal distance between the roots, the width of the buccolingual alveolar process, and buccal cortical bone thickness. All distances were recorded at five different levels from the cementoenamel junction (CEJ). Descriptive statistical analysis and t-tests were performed, with the significance level for all tests set at p<0.05. Patients with a Class II skeletal pattern showed significantly greater maxillary mesiodistal distances (between the first and second premolars) and widths of the buccolingual alveolar process (between the first and second molars) than Class I skeletal pattern patients at 10 mm above the CEJ. The maxillary buccal cortical bone thicknesses between the second premolar and first molar at 8 mm above the CEJ in Class II patients were likewise significantly greater than in Class I patients. Patients with a Class I skeletal pattern showed significantly wider mandibular buccolingual alveolar processes than did Class II patients (between the first and second molars) at 4, 6, and 8 mm below the CEJ. In both the maxilla and mandible, the mesiodistal distances, the width of the buccolingual alveolar process, and buccal cortical bone thickness tended to increase from the CEJ to the apex in both Class I and Class II skeletal patterns.

  14. Comparison of interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns using cone-beam computed tomography

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    Khumsarn, Nattida; Patanaporn, Virush; Jotikasthira, Dhirawat

    2016-01-01

    Purpose This study evaluated and compared interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns, using cone-beam computed tomography (CBCT). Materials and Methods Pretreatment CBCT images of 24 Thai orthodontic patients with Class I and Class II skeletal patterns were included in the study. Three measurements were chosen for investigation: the mesiodistal distance between the roots, the width of the buccolingual alveolar process, and buccal cortical bone thickness. All distances were recorded at five different levels from the cementoenamel junction (CEJ). Descriptive statistical analysis and t-tests were performed, with the significance level for all tests set at p<0.05. Results Patients with a Class II skeletal pattern showed significantly greater maxillary mesiodistal distances (between the first and second premolars) and widths of the buccolingual alveolar process (between the first and second molars) than Class I skeletal pattern patients at 10 mm above the CEJ. The maxillary buccal cortical bone thicknesses between the second premolar and first molar at 8 mm above the CEJ in Class II patients were likewise significantly greater than in Class I patients. Patients with a Class I skeletal pattern showed significantly wider mandibular buccolingual alveolar processes than did Class II patients (between the first and second molars) at 4, 6, and 8 mm below the CEJ. Conclusion In both the maxilla and mandible, the mesiodistal distances, the width of the buccolingual alveolar process, and buccal cortical bone thickness tended to increase from the CEJ to the apex in both Class I and Class II skeletal patterns. PMID:27358819

  15. Distribution of bone density and cortical thickness in the proximal femur and their association with hip fracture in postmenopausal women: a quantitative computed tomography study.

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    Yang, L; Udall, W J M; McCloskey, E V; Eastell, R

    2014-01-01

    The quantitative computed tomography (QCT) scans in an individually matched case-control study of women with hip fracture were analysed. There were widespread deficits in the femoral volumetric bone mineral density (vBMD) and cortical thickness of cases, and cortical vBMD and thickness discriminated hip fracture independently of BMD by dual-energy X-ray absorptiometry (DXA). Acknowledging the limitations of QCT associated with partial volume effects, we used QCT in an individually matched case-control study of women with hip fracture to better understand its structural basis. Fifty postmenopausal women (55-89 years) who had sustained hip fractures due to low-energy trauma underwent QCT scans of the contralateral hip within 3 months of the fracture. For each case, postmenopausal women, matched by age (±5 years), weight (±5 kg) and height (±5 cm), were recruited as controls. We quantified cortical, trabecular and integral vBMD and apparent cortical thickness (AppCtTh) in four quadrants of cross-sections along the length of the femoral head (FH), femoral neck (FN), intertrochanter and trochanter and examined their association with hip fracture. Women with hip or intracapsular (IC) fracture had significantly (p hip and IC fractures independent of hip areal BMD (aBMD). The combination of AppCtTh and trabecular or integral vBMD discriminated hip fracture, whereas the combination of FH and FN AppCtTh discriminated IC fracture significantly (p hip aBMD. Deficits in vBMD and AppCtTh in cases were widespread in the proximal femur, and cortical vBMD and AppCtTh discriminated hip fracture independently of aBMD by DXA.

  16. Quantitative radiology: radiogrammetry of cortical bone.

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    Dequeker, J

    1976-11-01

    reproducible method which measures bone mass indirectly. Changes in cortical width show a high degree of correlation with the changes in mass of cortical bones but trabecular bone is not measured. This is a serious handicap, since most of the metabolic diseases of the skeleton affect trabecular bone to a greater extent than cortical. Nevertheless the measurement of cortical thickness certainly has added to the knowledge of changes in bone mass in ageing and in disease.

  17. Cortical Thickness Changes Associated with Photoparoxysmal Response

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    Hanganu, Alexandru; Groppa, Stanislav A; Deuschl, Günther

    2014-01-01

    Photoparoxysmal response (PPR) is an EEG trait of spike and spike-wave discharges in response to photic stimulation that is closely linked to idiopathic generalized epilepsy (IGE). In our previous studies we showed that PPR is associated with functional alterations in the occipital and frontal co......) and compared these groups with a group of PPR-negative-healthy-controls (HC, n = 17; 15.3 ± 3.6 years; 6 males). Our results revealed an increase of cortical thickness in the occipital, frontal and parietal cortices bilaterally in PPR-positive-subjects in comparison to HC. Moreover PPR......-positive-subjects presented a significant decrease of cortical thickness in the temporal cortex in the same group contrast. IGE patients exhibited lower cortical thickness in the temporal lobe bilaterally and in the right paracentral region in comparison to PPR-positive-subjects. Our study demonstrates structural changes...... in the occipital lobe, frontoparietal regions and temporal lobe, which also show functional changes associated with PPR. Patients with epilepsy present changes in the temporal lobe and supplementary motor area....

  18. Swine cortical and cancellous bone: histomorphometric and densitometric characterisation

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    Maria Elena Andreis

    2017-06-01

    Full Text Available Introduction: Swine bone morphology, composition and remodelling are similar to humans’, therefore they are considered good models in bone-related research. They have been used for several studies involving bone growth, bone and cartilage fractures and femoral head osteonecrosis. Nevertheless, the literature about pig normal bone features is incomplete. This work aims to fill the literature gaps on the microarchitecture and Bone Mineral Density (BMD of swine femoral diaphysis and distal epiphysis and tibial plateau and diaphysis. Materials and methods: Five hind limbs were collected from slaughtered 80-100 kg pigs. Microscopic analysis of cortical and cancellous bone from middle/distal femur and proximal/middle tibia was performed to determine basic histomorphometric parameters at different sites. Dual-energy X-Rays Absorptiometry was also employed to evaluate BMD. ANOVA and correlation between BMD, bone area (BA and cortical thickness were performed. Results and discussion: Diaphyseal cortical bone was mostly plexiform both in the tibia and the femur; primary/secondary osteons without clear organization were also found. Mean values for bone area, bone perimeter, trabecular width, number and separation and BMD at different anatomical sites were defined. No significant difference was found for these values at different anatomical sites. BMD proved to be positively correlated with cortical thickness (r=0,80; p<0,01. Despite the small sample size, these results seem homogeneous. They could therefore represent reference values for normal bone parameters in pigs. Applied anatomy and regenerative medicine, in fact, demand very precise information about bone micromorphology, composition and density to provide reliable indication in bone substitutes building. Moreover, since the interpretation of bone abnormalities is based on mastering normal bone characteristics, the definition of reference parameters is mandatory to avoid misinterpretation and

  19. Relationship Between White Matter Hyperintensities, Cortical Thickness, and Cognition

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    Tuladhar, Anil M.; Norris, David Gordon

    2015-01-01

    Background and Purpose White matter hyperintensities (WMH) are associated with clinically heterogeneous symptoms that cannot be explained by these lesions alone. It is hypothesized that these lesions are associated with distant cortical atrophy and cortical thickness network measures, which can

  20. Cortical thickness abnormalities in late adolescence with online gaming addiction.

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    Kai Yuan

    Full Text Available Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18 and age-, education- and gender-matched controls (n = 18 were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC, insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction.

  1. Cortical thickness abnormalities in late adolescence with online gaming addiction.

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    Yuan, Kai; Cheng, Ping; Dong, Tao; Bi, Yanzhi; Xing, Lihong; Yu, Dahua; Zhao, Limei; Dong, Minghao; von Deneen, Karen M; Liu, Yijun; Qin, Wei; Tian, Jie

    2013-01-01

    Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18) and age-, education- and gender-matched controls (n = 18) were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC), insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction.

  2. Overweight is not associated with cortical thickness alterations in children

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    Rachel Jane Sharkey

    2015-02-01

    Full Text Available IntroductionSeveral studies report an association between body mass index (BMI and cortical thickness in adults. Some studies demonstrate diffuse cortical thinning in obesity, while others report effects in areas that are associated with self-regulation, such as lateral prefrontal cortex. MethodsThis study used multilevel modelling of data from the NIH Pediatric MRI Data Repository, a mixed longitudinal and cross-sectional database, to examine the relationship between cortical thickness and body weight in children. Cortical thickness was computed at 81,942 vertices of 716 MRI scans from 378 children aged between 4 and 18 years. Body mass index Z score for age was computed for each participant. We preformed vertex-wise statistical analysis of the relationship between cortical thickness and BMI, accounting for age and gender. In addition, cortical thickness was extracted from regions of interest in prefrontal cortex and insula.ResultsNo significant association between cortical thickness and BMI was found, either by statistical parametric mapping or by region of interest analysis. Results remained negative when the analysis was restricted to children aged 12-18.ConclusionsThe correlation between BMI and cortical thickness was not found in this large pediatric sample. The association between BMI and cortical thinning develops after adolescence. This has implications for the nature of the relationship between brain anatomy and weight gain.

  3. A new cortical thickness mapping method with application to an in vivo finite element model.

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    Kim, Young Ho; Kim, Jong-Eun; Eberhardt, Alan W

    2014-01-01

    Finite element modelling of musculoskeletal systems, with geometrical structures constructed from computed tomography (CT) scans, is a useful and powerful tool for biomechanical studies. The use of CT scans from living human subjects, however, is still limited. Accurate reconstruction of thin cortical bone structures from CT scans of living human subjects is especially problematic, due to low CT resolution that results from mandatory low radiation doses and/or involuntary movements of the subject. In this study, a new method for mapping cortical thickness is described. Using the method, cortical thickness measurements of a coxal (pelvis) bone obtained from CT scans of a cadaver were mapped to the coxal geometry as obtained through CT scans of a live human subject, resulting in accurate cortical thickness while maintaining geometric fidelity of the live subject. The mapping procedure includes shape-preserving parameterisation, mesh movement and interpolation of thickness using a search algorithm. The methodology is applicable to modelling of other bones where accurate cortical thickness is needed and for which such data exist.

  4. Age Effects on Cortical Thickness in Cognitively Normal Elderly Individuals

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    Sona Hurtz

    2014-07-01

    Full Text Available Background/Aims: Atrophy in both grey and white matter is found in normal aging. The prefrontal cortex and the frontal lobe white matter are thought to be the most affected regions. Our aim was to examine the effects of normal aging on cortical grey matter using a 3D quantitative cortical mapping method. Methods: We analyzed 1.5-tesla brain magnetic resonance imaging data from 44 cognitively normal elderly subjects using cortical pattern matching and cortical thickness analyses. Linear regression analysis was used to study the effect of age on cortical thickness. 3D map-wide correction for multiple comparisons was conducted with permutation analyses using a threshold of p Results: We found a significant negative association between age and cortical thickness in the right hemisphere (pcorrected = 0.009 and a trend level association in the left hemisphere (pcorrected = 0.081. Age-related changes were greatest in the sensorimotor, bilateral dorsal anterior cingulate and supplementary motor cortices, and the right posterior middle and inferior frontal gyri. Age effects greater in the medial than lateral visual association cortices were also seen bilaterally. Conclusion: Our novel method further validates that normal aging results in diffuse cortical thinning that is most pronounced in the frontal and visual association cortices.

  5. Technical Note: Cortical thickness and density estimation from clinical CT using a prior thickness-density relationship

    Energy Technology Data Exchange (ETDEWEB)

    Humbert, Ludovic, E-mail: ludohumberto@gmail.com [Galgo Medical, Barcelona 08036 (Spain); Hazrati Marangalou, Javad; Rietbergen, Bert van [Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands); Río Barquero, Luis Miguel del [CETIR Centre Medic, Barcelona 08029 (Spain); Lenthe, G. Harry van [Biomechanics Section, KU Leuven–University of Leuven, Leuven 3001 (Belgium)

    2016-04-15

    Purpose: Cortical thickness and density are critical components in determining the strength of bony structures. Computed tomography (CT) is one possible modality for analyzing the cortex in 3D. In this paper, a model-based approach for measuring the cortical bone thickness and density from clinical CT images is proposed. Methods: Density variations across the cortex were modeled as a function of the cortical thickness and density, location of the cortex, density of surrounding tissues, and imaging blur. High resolution micro-CT data of cadaver proximal femurs were analyzed to determine a relationship between cortical thickness and density. This thickness-density relationship was used as prior information to be incorporated in the model to obtain accurate measurements of cortical thickness and density from clinical CT volumes. The method was validated using micro-CT scans of 23 cadaver proximal femurs. Simulated clinical CT images with different voxel sizes were generated from the micro-CT data. Cortical thickness and density were estimated from the simulated images using the proposed method and compared with measurements obtained using the micro-CT images to evaluate the effect of voxel size on the accuracy of the method. Then, 19 of the 23 specimens were imaged using a clinical CT scanner. Cortical thickness and density were estimated from the clinical CT images using the proposed method and compared with the micro-CT measurements. Finally, a case-control study including 20 patients with osteoporosis and 20 age-matched controls with normal bone density was performed to evaluate the proposed method in a clinical context. Results: Cortical thickness (density) estimation errors were 0.07 ± 0.19 mm (−18 ± 92 mg/cm{sup 3}) using the simulated clinical CT volumes with the smallest voxel size (0.33 × 0.33 × 0.5 mm{sup 3}), and 0.10 ± 0.24 mm (−10 ± 115 mg/cm{sup 3}) using the volumes with the largest voxel size (1.0 × 1.0 × 3.0 mm{sup 3}). A trend for the

  6. Increased Cortical Thickness in Professional On-Line Gamers

    Science.gov (United States)

    Hyun, Gi Jung; Shin, Yong Wook; Kim, Bung-Nyun; Cheong, Jae Hoon; Jin, Seong Nam

    2013-01-01

    Objective The bulk of recent studies have tested whether video games change the brain in terms of activity and cortical volume. However, such studies are limited by several factors including cross-sectional comparisons, co-morbidity, and short-term follow-up periods. In the present study, we hypothesized that cognitive flexibility and the volume of brain cortex would be correlated with the career length of on-line pro-gamers. Methods High-resolution magnetic resonance scans were acquired in twenty-three pro-gamers recruited from StarCraft pro-game teams. We measured cortical thickness in each individual using FreeSurfer and the cortical thickness was correlated with the career length and the performance of the pro-gamers. Results Career length was positively correlated with cortical thickness in three brain regions: right superior frontal gyrus, right superior parietal gyrus, and right precentral gyrus. Additionally, increased cortical thickness in the prefrontal cortex was correlated with winning rates of the pro-game league. Increased cortical thickness in the prefrontal and parietal cortices was also associated with higher performance of Wisconsin Card Sorting Test. Conclusion Our results suggest that in individuals without pathologic conditions, regular, long-term playing of on-line games is associated with volume changes in the prefrontal and parietal cortices, which are associated with cognitive flexibility. PMID:24474988

  7. Increased cortical thickness in professional on-line gamers.

    Science.gov (United States)

    Hyun, Gi Jung; Shin, Yong Wook; Kim, Bung-Nyun; Cheong, Jae Hoon; Jin, Seong Nam; Han, Doug Hyun

    2013-12-01

    The bulk of recent studies have tested whether video games change the brain in terms of activity and cortical volume. However, such studies are limited by several factors including cross-sectional comparisons, co-morbidity, and short-term follow-up periods. In the present study, we hypothesized that cognitive flexibility and the volume of brain cortex would be correlated with the career length of on-line pro-gamers. High-resolution magnetic resonance scans were acquired in twenty-three pro-gamers recruited from StarCraft pro-game teams. We measured cortical thickness in each individual using FreeSurfer and the cortical thickness was correlated with the career length and the performance of the pro-gamers. CAREER LENGTH WAS POSITIVELY CORRELATED WITH CORTICAL THICKNESS IN THREE BRAIN REGIONS: right superior frontal gyrus, right superior parietal gyrus, and right precentral gyrus. Additionally, increased cortical thickness in the prefrontal cortex was correlated with winning rates of the pro-game league. Increased cortical thickness in the prefrontal and parietal cortices was also associated with higher performance of Wisconsin Card Sorting Test. Our results suggest that in individuals without pathologic conditions, regular, long-term playing of on-line games is associated with volume changes in the prefrontal and parietal cortices, which are associated with cognitive flexibility.

  8. Effect of porosity, tissue density, and mechanical properties on radial sound speed in human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Eneh, C. T. M., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Töyräs, J., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Jurvelin, J. S., E-mail: jukka.jurvelin@uef.fi [Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, Kuopio FI-70211, Finland and Diagnostic Imaging Center, Kuopio University Hospital, P.O. Box 100, Kuopio FI-70029 (Finland); Malo, M. K. H., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Liukkonen, J., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi [Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, Kuopio FI-70211 (Finland); Karjalainen, J. P., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi [Bone Index Finland Ltd., P.O. Box 1188, Kuopio FI-70211 (Finland)

    2016-05-15

    Purpose: The purpose of this study was to investigate the effect of simultaneous changes in cortical porosity, tissue mineral density, and elastic properties on radial speed of sound (SOS) in cortical bone. The authors applied quantitative pulse-echo (PE) ultrasound techniques that hold much potential especially for screening of osteoporosis at primary healthcare facilities. Currently, most PE measurements of cortical thickness, a well-known indicator of fracture risk, use a predefined estimate for SOS in bone to calculate thickness. Due to variation of cortical bone porosity, the use of a constant SOS value propagates to an unknown error in cortical thickness assessment by PE ultrasound. Methods: The authors conducted 2.25 and 5.00 MHz focused PE ultrasound time of flight measurements on femoral diaphyses of 18 cadavers in vitro. Cortical porosities of the samples were determined using microcomputed tomography and related to SOS in the samples. Additionally, the effect of cortical bone porosity and mechanical properties of the calcified matrix on SOS was investigated using numerical finite difference time domain simulations. Results: Both experimental measurements and simulations demonstrated significant negative correlation between radial SOS and cortical porosity (R{sup 2} ≥ 0.493, p < 0.01 and R{sup 2} ≥ 0.989, p < 0.01, respectively). When a constant SOS was assumed for cortical bone, the error due to variation of cortical bone porosity (4.9%–16.4%) was about 6% in the cortical thickness assessment in vitro. Conclusions: Use of a predefined, constant value for radial SOS in cortical bone, i.e., neglecting the effect of measured variation in cortical porosity, propagated to an error of 6% in cortical thickness. This error can be critical as characteristic cortical thinning of 1.10% ± 1.06% per yr decreases bending strength of the distal radius and results in increased fragility in postmenopausal women. Provided that the cortical porosity can be estimated

  9. 应用锥形束CT探究上颌前牙区颌骨微种植支抗钉植入的安全区%Quantitative study of maxillary anterior bone depth and labial cortical bone thickness for micro- implant anchorage placement using cone beam CT

    Institute of Scientific and Technical Information of China (English)

    赵岩; 吴平

    2012-01-01

    目的:对上颌前牙区颌骨的骨量及唇侧骨皮质厚度进行测量分析,为正畸治疗植入微种植支抗钉的安全区提供参考.方法:对25例成人患者上颌前牙区行锥形束CT扫描及三维重建,测量距上颌牙槽嵴顶3、6、9、12mm水平上颌中切牙、侧切牙、尖牙根间区近远中向、唇腭向的距离以及唇侧骨皮质厚度.结果:在距上颌牙槽嵴顶3、6、9mm水平中切牙根间近远中向距离均最宽,唇侧骨皮质均最薄;在距牙槽嵴顶9mm水平中切牙与侧切牙根间近远中向距离最窄;在4个测量水平侧切牙与尖牙根间唇侧骨皮质均最厚;唇腭向在距牙槽嵴顶9mm及以上水平,中切牙根间骨厚度最薄,中切牙与侧切牙根间骨厚度最厚.25例中仅3例前牙区各牙根长度超过12mm,在距牙槽嵴顶12mm水平测出的根间近远中向距离均较宽.结论:通过对扫描后颌骨影像的分析,明确了前牙区颌骨的骨量及唇侧骨皮质厚度,为植入微种植支抗钉的安全区提供参考.%Objective: To investigate the bone depth and labial cortical bone thickness of maxillary anterior interdental area for orthodontic micro-implant anchorage. Methods; Maxillary anterior alveolar bone of 25 adults was scanned and reconstructed by cone beam CT, the mesio-distal interdental distance, labial-palatal bone depth and labial cortical bone thickness were measured at 3, 6, 9 and 12 mm from the alveolar crest between upper anterior dental roots. Results; The mesio-distal distance between central incisors was the widest in all measurement levels, while the labial cortical bone thickness was the thinnest. At the 9 mm-level, the shortest mesio-distal distance was between the roots of central and lateral incisors. The labial cortical bone thickness between lateral incisors and canines was the thickest in all measurement levels. At or above the 9 mm-level, the labial-palatal bone depth was the thinnest between central incisors, but the thickest

  10. Increased brain cortical thickness associated with visceral fat in adolescents.

    Science.gov (United States)

    Saute, R L; Soder, R B; Alves Filho, J O; Baldisserotto, M; Franco, A R

    2016-10-27

    There has been a growing amount of evidence indicating that excess visceral fat is associated with alterations in brain structure and function, including brain cortical thinning in adults. This study aims to investigate the relationship between brain cortical thickness with obesity assessments, in adolescents. In this study, we measured three different obesity assessments within an adolescent population (aged 15 - 18 years): body mass index (BMI), visceral fat ratio measured with an MRI and hepatorenal gradient measured with an ultrasound. Volunteers also underwent an MRI scan to measure brain structure. Results indicated that there was no relationship of BMI or hepatorenal gradient with brain cortical dimensions. However, there was a significant association between visceral fat ratio and an increase of cortical thickness throughout the brain. These results suggest that visceral fat, but not BMI, is correlated with cortical thickening in adolescence. © 2016 World Obesity Federation.

  11. Calcium phosphate cement augmentation of cancellous bone screws can compensate for the absence of cortical fixation.

    Science.gov (United States)

    Stadelmann, Vincent A; Bretton, Elise; Terrier, Alexandre; Procter, Philip; Pioletti, Dominique P

    2010-11-16

    An obvious means to improve the fixation of a cancellous bone screw is to augment the surrounding bone with cement. Previous studies have shown that bone augmentation with Calcium Phosphate (CaP) cement significantly improves screw fixation. Nevertheless, quantitative data about the optimal distribution of CaP cement is not available. The present study aims to show the effect of cement distribution on the screw fixation strength for various cortical thicknesses and to determine the conditions at which cement augmentation can compensate for the absence of cortical fixation in osteoporotic bone. In this study, artificial bone materials were used to mimic osteoporotic cancellous bone and cortical bone of varying thickness. These bone constructs were used to test the fixation strength of cancellous bone screws in different cortical thicknesses and different cement augmentation depths. The cement distribution was measured with microCT. The maximum pullout force was measured experimentally. The microCT analysis revealed a pseudo-conic shape distribution of the cement around the screws. While the maximum pullout strength of the screws in the artificial bone only was 30±7N, it could increase up to approximately 1000N under optimal conditions. Cement augmentation significantly increased pullout force in all cases. The effect of cortical thickness on pullout force was reduced with increased cement augmentation depth. Indeed, cement augmentation without cortical fixation increased pullout forces over that of screws without cement augmentation but with cortical fixation. Since cement augmentation significantly increased pullout force in all cases, we conclude that the loss of cortical fixation can be compensated by cement augmentation.

  12. Relationship between the CT Value and Cortical Bone Thickness at Implant Recipient Sites and Primary Implant Stability with Comparison of Different Implant Types.

    Science.gov (United States)

    Howashi, Miori; Tsukiyama, Yoshihiro; Ayukawa, Yasunori; Isoda-Akizuki, Kei; Kihara, Masafumi; Imai, Yu; Sogo, Motofumi; Koyano, Kiyoshi

    2016-02-01

    Studies have shown that bone quality at the implant recipient site can influence primary stability. The aims of this study were to explore the quantitative estimation of the primary stability of implants preoperatively using CT values and to examine the effect of different implant designs with recommended socket preparation on primary stability. Forty-four fresh porcine femoral heads were prepared. The bone surrounding implant sockets was preoperatively evaluated by helical CT. Forty-four implants (φ 4.3 × 10 mm), 22 straight and 22 tapered, were placed according to the manufacturer's instructions. The insertion torque value (ITV), implant stability quotient (ISQ), and removal torque value (RTV) were recorded as indicators of primary implant stability. Significant correlations and linear relationships were found between the CT value and ITV, ISQ, and RTV for both straight and tapered implants (Spearman's correlation coefficient, p quantitatively estimated using the CT value preoperatively, indicating the CT value of bone surrounding an implant can contribute considerably to implant planning and design choice in clinical situations. © 2014 Wiley Periodicals, Inc.

  13. 老年肱骨近端骨折患者皮质骨厚度与骨密度相关性分析%Analysis of the association between proximal humeral cortical bone thickness and bone mineral ;density in elderly proximal humeral fracture patients

    Institute of Scientific and Technical Information of China (English)

    张玺; 胡永成; 耿欣; 陈菲; 李健

    2015-01-01

    Objective To explore the possible association between proximal humeral cortical bone thickness and bone mineral density (BMD) in elderly patients with proximal humeral fractures. Methods We scaned 69 cases of the shoulders in elderly proximal humeral fracture patients and measured the average cortical bone thickness in two different CT layers with picture archiving and communication system (PACS). BMD was measured with dual-energy x-ray absorptiometry (DXA). Spearman correlations were used to assess the relationship between cortical bone thickness and BMD of femoral neck and lumbar vertebra. Results The study group was consisted of 69 cases, including 18 males and 51 females. About 65% of female and 16% of male were complicated by osteoporosis, The BMD of lumber and femoral neck were better in male patients than female patients (P<0.05), and in male osteoporosis patients than female osteoprosis patients (P<0.05). The BMD of lumber and femoral neck in all patients were closely related to average cortical bone thickness, and the same result was found in osteoporosis patients. Conclusion The measurement technique of average cortical bone thickness with CT and PACS is a quick and accurate method, which complements for DXA.%目的探讨老年肱骨近端骨折患者肱骨近端骨皮质厚度与骨密度(bone mineral density,BMD)的相关性。方法使用螺旋CT机对69例老年肱骨近端骨折患者的肩关节进行扫描后在图像工作站影像归档和通信系统处理软件中对两个水平层面图像的皮质骨厚度进行测量并取平均数,BMD值使用双能X线BMD测量仪测量获得,采用Spearman等级相关分析方法对腰椎和股骨颈处BMD与平均皮质骨厚度相关性进行计算。结果69例患者中,男18例、女51例,女性骨质疏松者占全部病例的65%,男性骨质疏松者占全部病例的16%。男性患者腰椎、股骨颈处BMD和平均皮质骨厚度均优于女性(P<0.05),骨质疏松患者

  14. Multiscale and multimodality computed tomography for cortical bone analysis

    Science.gov (United States)

    Ostertag, A.; Peyrin, F.; Gouttenoire, P. J.; Laredo, J. D.; DeVernejoul, M. C.; Cohen Solal, M.; Chappard, C.

    2016-12-01

    In clinical studies, high resolution peripheral quantitative computed tomography (HR-pQCT) is used to separately evaluate cortical bone and trabecular bone with an isotropic voxel of 82 µm3, and typical cortical parameters are cortical density (D.comp), thickness (Ct.Th), and porosity (Ct.Po). In vitro, micro-computed tomography (micro-CT) is used to explore the internal cortical bone micro-structure with isotropic voxels and high resolution synchrotron radiation (SR); micro-CT is considered the ‘gold standard’. In 16 tibias and 8 femurs, HR-pQCT measurements were compared to conventional micro-CT measurements. To test modality effects, conventional micro-CT measurements were compared to SR micro-CT measurements at 7.5 µm3 SR micro-CT measurements were also tested at different voxel sizes for the femurs, specifically, 7.5 µm3 versus 2.8 µm3. D.comp (r  =  -0.88, p  images provided consistent results compared to those obtained using conventional micro-CT at the distal tibia. D.comp was highly correlated to Po.V/TV because it considers both the micro-porosity (Haversian systems) and macro-porosity (resorption lacunae) of cortical bone. The complexity of canal organization, (including shape, connectivity, and surface) are not fully considered in conventional micro-CT in relation to beam hardening and cone beam reconstruction artifacts. With the exception of Po.V/TV measurements, morphological and topological measurements depend on the characteristics of the x-ray beam, and to a lesser extent, on image resolution.

  15. Trabecular bone of growth plate origin influences both trabecular and cortical morphology in adulthood.

    Science.gov (United States)

    Wang, Qingju; Ghasem-Zadeh, Ali; Wang, Xiao-Fang; Iuliano-Burns, Sandra; Seeman, Ego

    2011-07-01

    Skeletal fragility is common at metaphyseal regions of long bones. The cortices of this region are derived by coalescence of trabeculae around the periphery of the growth plate, not by periosteal apposition, as occurs in the diaphyses. We therefore hypothesized that trabecular bone in childhood predicted both cortical and trabecular morphology in adulthood. To test this hypothesis, we measured distal radial and tibial structure using high-resolution peripheral quantitative computed tomography in 61 daughter-mother pairs, mean age 12.5 years (range 7 to 19 years) and 44.1 years (range 32 to 50 years), respectively. The daughters' trabecular bone volume (BV/TV), thickness, number, and separation predicted the corresponding traits in their mothers. Their trabecular BV/TV also predicted their mothers' cortical thickness (r = 0.32, p = .02). By contrast, the daughters' cortical thickness did not predict their mothers' cortical thickness. The daughters had higher trabecular BV/TV than their mothers (mean ± SD, radius 0.134 ± 0.024 versus 0.124 ± 0.033, p = .03; tibia 0.145 ± 0.021 versus 0.135 ± 0.032, p < .01) owing to greater trabecular number, not thickness, and less trabecular separation. Abnormalities in the development of metaphyseal trabecular bone are likely to influence fragility in both trabecular and cortical bone of this region in adulthood.

  16. Osteocyte lacunar properties in rat cortical bone

    DEFF Research Database (Denmark)

    Bach-Gansmo, Fiona Linnea; Weaver, James C.; Jensen, Mads Hartmann

    2015-01-01

    to osteocyte function, osteocyte lacunar properties such as volume, shape, orientation, and density are now frequently reported in studies investigating osteocyte activity. Despite this increasing interest in lacunar morphometrics, many studies show a large spread in such values, suggesting a large inter......-species but also inter-site variation in lacunar properties. Here, osteocyte lacunae in rat cortical bone have been studied using synchrotron radiation micro computed tomography (SR μCT) and backscattered electron (BE) microscopy. Quantitative lacunar geometric characteristics are reported based on the synchrotron...... radiation data, differentiating between circumferential lamellar bone and a central, more disordered bone type. From these studies, no significant differences were found in lacunar volumes between lamellar and central bone, whereas significant differences in lacunar orientation, shape and density values...

  17. Growth hormone effects on cortical bone dimensions in young adults with childhood-onset growth hormone deficiency

    DEFF Research Database (Denmark)

    Hyldstrup, L; Conway, G S; Racz, K

    2012-01-01

    Growth hormone (GH) treatment in young adults with childhood-onset GH deficiency has beneficial effects on bone mass. The present study shows that cortical bone dimensions also benefit from GH treatment, with endosteal expansion and increased cortical thickness leading to improved bone strength....... INTRODUCTION: In young adults with childhood-onset growth hormone deficiency (CO GHD), GH treatment after final height is reached has been shown to have beneficial effects on spine and hip bone mineral density. The objective of the study was to evaluate the influence of GH on cortical bone dimensions. METHODS......: Patients (n = 160; mean age, 21.2 years; 63% males) with CO GHD were randomised 2:1 to GH or no treatment for 24 months. Cortical bone dimensions were evaluated by digital x-ray radiogrammetry of the metacarpal bones every 6 months. RESULTS: After 24 months, cortical thickness was increased compared...

  18. The myokine irisin increases cortical bone mass

    Science.gov (United States)

    Colaianni, Graziana; Cuscito, Concetta; Mongelli, Teresa; Pignataro, Paolo; Buccoliero, Cinzia; Liu, Peng; Lu, Ping; Sartini, Loris; Di Comite, Mariasevera; Mori, Giorgio; Di Benedetto, Adriana; Brunetti, Giacomina; Yuen, Tony; Sun, Li; Reseland, Janne E.; Colucci, Silvia; New, Maria I.; Zaidi, Mone; Cinti, Saverio; Grano, Maria

    2015-01-01

    It is unclear how physical activity stimulates new bone synthesis. We explored whether irisin, a newly discovered myokine released upon physical activity, displays anabolic actions on the skeleton. Young male mice were injected with vehicle or recombinant irisin (r-irisin) at a low cumulative weekly dose of 100 µg kg−1. We observed significant increases in cortical bone mass and strength, notably in cortical tissue mineral density, periosteal circumference, polar moment of inertia, and bending strength. This anabolic action was mediated primarily through the stimulation of bone formation, but with parallel notable reductions in osteoclast numbers. The trabecular compartment of the same bones was spared, as were vertebrae from the same mice. Higher irisin doses (3,500 µg kg−1 per week) cause browning of adipose tissue; this was not seen with low-dose r-irisin. Expectedly, low-dose r-irisin modulated the skeletal genes, Opn and Sost, but not Ucp1 or Pparγ expression in white adipose tissue. In bone marrow stromal cell cultures, r-irisin rapidly phosphorylated Erk, and up-regulated Atf4, Runx2, Osx, Lrp5, β-catenin, Alp, and Col1a1; this is consistent with a direct receptor-mediated action to stimulate osteogenesis. We also noted that, although the irisin precursor Fndc5 was expressed abundantly in skeletal muscle, other sites, such as bone and brain, also expressed Fndc5, albeit at low levels. Furthermore, muscle fibers from r-irisin–injected mice displayed enhanced Fndc5 positivity, and irisin induced Fdnc5 mRNA expression in cultured myoblasts. Our data therefore highlight a previously unknown action of the myokine irisin, which may be the molecular entity responsible for muscle–bone connectivity. PMID:26374841

  19. Associations between children's socioeconomic status and prefrontal cortical thickness.

    Science.gov (United States)

    Lawson, Gwendolyn M; Duda, Jeffrey T; Avants, Brian B; Wu, Jue; Farah, Martha J

    2013-09-01

    Childhood socioeconomic status (SES) predicts executive function performance and measures of prefrontal cortical function, but little is known about its anatomical correlates. Structural MRI and demographic data from a sample of 283 healthy children from the NIH MRI Study of Normal Brain Development were used to investigate the relationship between SES and prefrontal cortical thickness. Specifically, we assessed the association between two principal measures of childhood SES, family income and parental education, and gray matter thickness in specific subregions of prefrontal cortex and on the asymmetry of these areas. After correcting for multiple comparisons and controlling for potentially confounding variables, parental education significantly predicted cortical thickness in the right anterior cingulate gyrus and left superior frontal gyrus. These results suggest that brain structure in frontal regions may provide a meaningful link between SES and cognitive function among healthy, typically developing children. © 2013 John Wiley & Sons Ltd.

  20. Insertion torque versus mechanical resistance of mini-implants inserted in different cortical thickness

    Science.gov (United States)

    Santos, Renata de Faria; Ruellas, Antonio Carlos de Oliveira; Fernandes, Daniel Jogaib; Elias, Carlos Nelson

    2014-01-01

    Objective This study aimed to measure insertion torque, tip mechanical resistance to fracture and transmucosal neck of mini-implants (MI) (Conexão Sistemas de PróteseT), as well as to analyze surface morphology. Methods Mechanical tests were carried out to measure the insertion torque of MIs in different cortical thicknesses, and tip mechanical resistance to fracture as well as transmucosal neck of MIs. Surface morphology was assessed by scanning electron microscopy (SEM) before and after the mechanical tests. Results Values of mechanical resistance to fracture (22.14 N.cm and 54.95 N.cm) were higher and statistically different (P 0.05) to torsional fracture in the tip of MI (22.14 N.cm) when 3 mm cortical thickness (16.11 N.cm) and dense bone (23.95 N.cm) were used. Torsional fracture of the transmucosal neck (54.95 N.cm) was higher and statistically different (P implants tested presented adequate surface morphology. The resistance of mini-implants to fracture safely allows placement in 1 and 2-mm cortical thickness. However, in 3-mm cortical thickness and dense bones, pre-drilling with a bur is recommended before insertion. PMID:25162571

  1. Genetic determinants of trabecular and cortical volumetric bone mineral densities and bone microstructure.

    Directory of Open Access Journals (Sweden)

    Lavinia Paternoster

    Full Text Available Most previous genetic epidemiology studies within the field of osteoporosis have focused on the genetics of the complex trait areal bone mineral density (aBMD, not being able to differentiate genetic determinants of cortical volumetric BMD (vBMD, trabecular vBMD, and bone microstructural traits. The objective of this study was to separately identify genetic determinants of these bone traits as analysed by peripheral quantitative computed tomography (pQCT. Separate GWA meta-analyses for cortical and trabecular vBMDs were performed. The cortical vBMD GWA meta-analysis (n = 5,878 followed by replication (n = 1,052 identified genetic variants in four separate loci reaching genome-wide significance (RANKL, rs1021188, p = 3.6×10⁻¹⁴; LOC285735, rs271170, p = 2.7×10⁻¹²; OPG, rs7839059, p = 1.2×10⁻¹⁰; and ESR1/C6orf97, rs6909279, p = 1.1×10⁻⁹. The trabecular vBMD GWA meta-analysis (n = 2,500 followed by replication (n = 1,022 identified one locus reaching genome-wide significance (FMN2/GREM2, rs9287237, p = 1.9×10⁻⁹. High-resolution pQCT analyses, giving information about bone microstructure, were available in a subset of the GOOD cohort (n = 729. rs1021188 was significantly associated with cortical porosity while rs9287237 was significantly associated with trabecular bone fraction. The genetic variant in the FMN2/GREM2 locus was associated with fracture risk in the MrOS Sweden cohort (HR per extra T allele 0.75, 95% confidence interval 0.60-0.93 and GREM2 expression in human osteoblasts. In conclusion, five genetic loci associated with trabecular or cortical vBMD were identified. Two of these (FMN2/GREM2 and LOC285735 are novel bone-related loci, while the other three have previously been reported to be associated with aBMD. The genetic variants associated with cortical and trabecular bone parameters differed, underscoring the complexity of the genetics of bone parameters. We propose

  2. Cranial vault thickness in primates: Homo erectus does not have uniquely thick vault bones.

    Science.gov (United States)

    Copes, Lynn E; Kimbel, William H

    2016-01-01

    Extremely thick cranial vaults have been noted as a diagnostic characteristic of Homo erectus since the first fossil of the species was identified, but relatively little work has been done on elucidating its etiology or variation across fossils, living humans, or extant non-human primates. Cranial vault thickness (CVT) is not a monolithic trait, and the responsiveness of its layers to environmental stimuli is unknown. We obtained measurements of cranial vault thickness in fossil hominins from the literature and supplemented those data with additional measurements taken on African fossil specimens. Total CVT and the thickness of the cortical and diploë layers individually were compared to measures of CVT in extant species measured from more than 500 CT scans of human and non-human primates. Frontal and parietal CVT in fossil primates was compared to a regression of CVT on cranial capacity calculated for extant species. Even after controlling for cranial capacity, African and Asian H. erectus do not have uniquely high frontal or parietal thickness residuals, either among hominins or extant primates. Extant primates with residual CVT thickness similar to or exceeding H. erectus (depending on the sex and bone analyzed) include Nycticebus coucang, Perodicticus potto, Alouatta caraya, Lophocebus albigena, Galago alleni, Mandrillus sphinx, and Propithecus diadema. However, the especially thick vaults of extant non-human primates that overlap with H. erectus values are composed primarily of cortical bone, while H. erectus and other hominins have diploë-dominated vault bones. Thus, the combination of thick vaults comprised of a thickened diploë layer may be a reliable autapomorphy for members of the genus Homo.

  3. Cortical bone total ossicular replacement prosthesis

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    Manu Malhotra

    2014-01-01

    Full Text Available Objectives: Evaluate an autologous cortical bone total ossicular replacement prosthesis (B TORP made of cortical bone for cost effective and sustainable hearing results. Materials and Methods: A prospective study was undertaken in the patients who underwent tympanoplasty with new B-TORP from January 2011 to December 2011. All patients had an absent superstructure of the stapes and long process of the incus due to chronic otitis media. Totally 40 patients were evaluated. Hearing results were evaluated using four-frequency average pure tone air conduction and air-bone gap (ABG measured at 0.5, 1, 2, and 3 kHz after a period of 12 months. Pre- and post-operative continuous variables were compared using a paired t-test and data from unequal groups were assessed for significant differences using unpaired t-test. Results: Successful rehabilitation of the ABG to 20 dB or less was achieved in 95% of patients. Overall mean improvement in ABG was 25.8 ± 5.6 dB, which was statistically significant (t = 26.8, P 0.5. Conclusion: The new autologous B-TORP provides sustainable hearing improvement and is bio-compatible, stable, and magnetic resonance imaging compatible.

  4. Longitudinal changes in cortical thickness in autism and typical development

    Science.gov (United States)

    Prigge, Molly B. D.; Nielsen, Jared A.; Froehlich, Alyson L.; Abildskov, Tracy J.; Anderson, Jeffrey S.; Fletcher, P. Thomas; Zygmunt, Kristen M.; Travers, Brittany G.; Lange, Nicholas; Alexander, Andrew L.; Bigler, Erin D.; Lainhart, Janet E.

    2014-01-01

    The natural history of brain growth in autism spectrum disorders remains unclear. Cross-sectional studies have identified regional abnormalities in brain volume and cortical thickness in autism, although substantial discrepancies have been reported. Preliminary longitudinal studies using two time points and small samples have identified specific regional differences in cortical thickness in the disorder. To clarify age-related trajectories of cortical development, we examined longitudinal changes in cortical thickness within a large mixed cross-sectional and longitudinal sample of autistic subjects and age- and gender-matched typically developing controls. Three hundred and forty-five magnetic resonance imaging scans were examined from 97 males with autism (mean age = 16.8 years; range 3–36 years) and 60 males with typical development (mean age = 18 years; range 4–39 years), with an average interscan interval of 2.6 years. FreeSurfer image analysis software was used to parcellate the cortex into 34 regions of interest per hemisphere and to calculate mean cortical thickness for each region. Longitudinal linear mixed effects models were used to further characterize these findings and identify regions with between-group differences in longitudinal age-related trajectories. Using mean age at time of first scan as a reference (15 years), differences were observed in bilateral inferior frontal gyrus, pars opercularis and pars triangularis, right caudal middle frontal and left rostral middle frontal regions, and left frontal pole. However, group differences in cortical thickness varied by developmental stage, and were influenced by IQ. Differences in age-related trajectories emerged in bilateral parietal and occipital regions (postcentral gyrus, cuneus, lingual gyrus, pericalcarine cortex), left frontal regions (pars opercularis, rostral middle frontal and frontal pole), left supramarginal gyrus, and right transverse temporal gyrus, superior parietal lobule, and

  5. Longitudinal changes in cortical thickness associated with normal aging.

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    Thambisetty, Madhav; Wan, Jing; Carass, Aaron; An, Yang; Prince, Jerry L; Resnick, Susan M

    2010-10-01

    Imaging studies of anatomic changes in regional gray matter volumes and cortical thickness have documented age effects in many brain regions, but the majority of such studies have been cross-sectional investigations of individuals studied at a single point in time. In this study, using serial imaging assessments of participants in the Baltimore Longitudinal Study of Aging (BLSA), we investigate longitudinal changes in cortical thickness during aging in a cohort of 66 older adults (mean age 68.78; sd. 6.6; range 60-84 at baseline) without dementia. We used the Cortical Reconstruction Using Implicit Surface Evolution CRUISE suite of algorithms to automatically generate a reconstruction of the cortical surface and identified twenty gyral based regions of interest per hemisphere. Using mixed effects regression, we investigated longitudinal changes in these regions over a mean follow-up interval of 8 years. The main finding in this study is that age-related decline in cortical thickness is widespread, but shows an anterior-posterior gradient with frontal and parietal regions, in general, exhibiting greater rates of decline than temporal and occipital. There were fewer regions in the right hemisphere showing statistically significant age-associated longitudinal decreases in mean cortical thickness. Males showed greater rates of decline in the middle frontal, inferior parietal, parahippocampal, postcentral, and superior temporal gyri in the left hemisphere, right precuneus and bilaterally in the superior parietal and cingulate regions. Significant nonlinear changes over time were observed in the postcentral, precentral, and orbitofrontal gyri on the left and inferior parietal, cingulate, and orbitofrontal gyri on the right.

  6. Cortical thickness mapping to identify focal osteoporosis in patients with hip fracture.

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    Kenneth E S Poole

    Full Text Available BACKGROUND: Individuals with osteoporosis are predisposed to hip fracture during trips, stumbles or falls, but half of all hip fractures occur in those without generalised osteoporosis. By analysing ordinary clinical CT scans using a novel cortical thickness mapping technique, we discovered patches of markedly thinner bone at fracture-prone regions in the femurs of women with acute hip fracture compared with controls. METHODS: We analysed CT scans from 75 female volunteers with acute fracture and 75 age- and sex-matched controls. We classified the fracture location as femoral neck or trochanteric before creating bone thickness maps of the outer 'cortical' shell of the intact contra-lateral hip. After registration of each bone to an average femur shape and statistical parametric mapping, we were able to visualise and quantify statistically significant foci of thinner cortical bone associated with each fracture type, assuming good symmetry of bone structure between the intact and fractured hip. The technique allowed us to pinpoint systematic differences and display the results on a 3D average femur shape model. FINDINGS: The cortex was generally thinner in femoral neck fracture cases than controls. More striking were several discrete patches of statistically significant thinner bone of up to 30%, which coincided with common sites of fracture initiation (femoral neck or trochanteric. INTERPRETATION: Femoral neck fracture patients had a thumbnail-sized patch of focal osteoporosis at the upper head-neck junction. This region coincided with a weak part of the femur, prone to both spontaneous 'tensile' fractures of the femoral neck, and as a site of crack initiation when falling sideways. Current hip fracture prevention strategies are based on case finding: they involve clinical risk factor estimation to determine the need for single-plane bone density measurement within a standard region of interest (ROI of the femoral neck. The precise sites of focal

  7. Propagation of time-reversed Lamb waves in bovine cortical bone in vitro.

    Science.gov (United States)

    Lee, Kang Il; Yoon, Suk Wang

    2015-01-01

    The present study aims to investigate the propagation of time-reversed Lamb waves in bovine cortical bone in vitro. The time-reversed Lamb waves were successfully launched at 200 kHz in 18 bovine tibiae through a time reversal process of Lamb waves. The group velocities of the time-reversed Lamb waves in the bovine tibiae were measured using the axial transmission technique. They showed a significant correlation with the cortical thickness and tended to follow the theoretical group velocity of the lowest order antisymmetrical Lamb wave fairly well, consistent with the behavior of the slow guided wave in long cortical bones.

  8. The Hounsfield value for cortical bone geometry in the proximal humerus - an in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Lim Fat, Daren; Kennedy, Jim; Galvin, Rose; O' Brien, Fergal; Mc Grath, Frank; Mullett, Hannan [Royal College of Surgeons in Ireland, Investigations Carried Out at Anatomy Lab, Dublin (Ireland)

    2012-05-15

    Fractures of the proximal humerus represent a major osteoporotic burden. Recent developments in CT imaging have emphasized the importance of cortical bone thickness distribution in the prevention and management of fragility fractures. We aimed to experimentally define the CT density of cortical bone in the proximal humerus for building cortical geometry maps. With ethical approval, we used ten fresh-frozen human proximal humeri. These were stripped of all soft tissue and high-resolution CT images were then taken. The humeral heads were then subsequently resected to allow access to the metaphyseal area. Using curettes, cancellous bone was removed down to hard cortical bone. Another set of CT images of the reamed specimen was then taken. Using CT imaging software and a CAD interface, we then compared cortical contours at different CT density thresholds to the reference inner cortical contour of our reamed specimens. Working with 3D model representations of these cortical maps, we were able to accurately make distance comparison analyses based on different CT thresholds. We could compute a single closest value at 700 HU. No difference was found in the HU-based contours generated along the 500-900 HU pixels (p = 1.000). The contours were significantly different from those generated at 300, 400, 1,000, and 1,100 HU. A Hounsfield range of 500-900 HU can accurately depict cortical bone geometry in the proximal humerus. Thresholding outside this range leads to statistically significant inaccuracies. Our results concur with a similar range reported in the literature for the proximal femur. Knowledge of regional variations in cortical bone thickness has direct implications for basic science studies on osteoporosis and its treatment, but is also important for the orthopedic surgeon since our decision for treatment options is often guided by local bone quality. (orig.)

  9. Thermographic stress analysis in cortical bone.

    Science.gov (United States)

    Vanderby, R; Kohles, S S

    1991-11-01

    Under adiabatic (or near adiabatic) conditions a volumetric change in an elastic material will produce a corresponding change in temperature. Based upon this principle, thermographic stress analysis (TSA) measures changes in surface heat flux (which are related to changes in surface temperature) and relates them to a coupled form of strains or stresses. To demonstrate the feasibility of using this technique for biomechanical applications, we thermographically measured heat flux from loaded specimens of cortical bone and correlated the results with strain gage data. Regular parallelepipeds were cut from the cortex of bovine femora and loaded sinusoidally at 20 Hz. At this rate of loading, mechanically induced changes in surface temperature could be sampled (via heat flux) prior to a measureable attenuation of the thermoelastic effect. Correlation coefficients demonstrated a significant linear relationship between TSA and measured and computed mechanical parameters (stress, strain, first strain invariant, and strain energy density). TSA therefore appears to be a promising technology for experimental stress analysis in cortical bone.

  10. Reduced cortical thickness associated with visceral fat and BMI

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    Ralf Veit

    2014-01-01

    Full Text Available Structural brain imaging studies have shown that obesity is associated with widespread reductions in gray matter (GM volume. Although the body mass index (BMI is an easily accessible anthropometric measure, substantial health problems are more related to specific body fat compartments, like visceral adipose tissue (VAT. We investigated cortical thickness measures in a group of 72 healthy subjects (BMI range 20–35 kg/m2, age range 19–50 years. Multiple regression analyses were performed using VAT and BMI as predictors and age, gender, total surface area and education as confounds. BMI and VAT were independently associated with reductions in cortical thickness in clusters comprising the left lateral occipital area, the left inferior temporal cortex, and the left precentral and inferior parietal area, while the right insula, the left fusiform gyrus and the right inferior temporal area showed a negative correlation with VAT only. In addition, we could show significant reductions in cortical thickness with increasing VAT adjusted for BMI in the left temporal cortex. We were able to detect widespread cortical thinning in a young to middle-aged population related to BMI and VAT; these findings show close resemblance to studies focusing on GM volume differences in diabetic patients. This may point to the influence of VAT related adverse effects, like low-grade inflammation, as a potentially harmful factor on brain integrity already in individuals at risk of developing diabetes, metabolic syndromes and arteriosclerosis.

  11. Cortical thickness and brain volumetric analysis in body dysmorphic disorder.

    Science.gov (United States)

    Madsen, Sarah K; Zai, Alex; Pirnia, Tara; Arienzo, Donatello; Zhan, Liang; Moody, Teena D; Thompson, Paul M; Feusner, Jamie D

    2015-04-30

    Individuals with body dysmorphic disorder (BDD) suffer from preoccupations with perceived defects in physical appearance, causing severe distress and disability. Although BDD affects 1-2% of the population, the neurobiology is not understood. Discrepant results in previous volumetric studies may be due to small sample sizes, and no study has investigated cortical thickness in BDD. The current study is the largest neuroimaging analysis of BDD. Participants included 49 medication-free, right-handed individuals with DSM-IV BDD and 44 healthy controls matched by age, sex, and education. Using high-resolution T1-weighted magnetic resonance imaging, we computed vertex-wise gray matter (GM) thickness on the cortical surface and GM volume using voxel-based morphometry. We also computed volumes in cortical and subcortical regions of interest. In addition to group comparisons, we investigated associations with symptom severity, insight, and anxiety within the BDD group. In BDD, greater anxiety was significantly associated with thinner GM in the left superior temporal cortex and greater GM volume in the right caudate nucleus. There were no significant differences in cortical thickness, GM volume, or volumes in regions of interest between BDD and control subjects. Subtle associations with clinical symptoms may characterize brain morphometric patterns in BDD, rather than large group differences in brain structure. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Tensile mechanical properties of swine cortical mandibular bone.

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    Tamar Brosh

    Full Text Available Temporary orthodontic mini implants serve as anchorage devices in orthodontic treatments. Often, they are inserted in the jaw bones, between the roots of the teeth. The stability of the mini implants within the bone is one of the major factors affecting their success and, consequently, that of the orthodontic treatment. Bone mechanical properties are important for implant stability. The aim of this study was to determine the tensile properties of the alveolar and basal mandible bones in a swine model. The diametral compression test was employed to study the properties in two orthogonal directions: mesio-distal and occluso-gingival. Small cylindrical cortical bone specimens (2.6 mm diameter, 1.5 mm thickness were obtained from 7 mandibles using a trephine drill. The sites included different locations (anterior and posterior and aspects (buccal and lingual for a total of 16 specimens from each mandible. The load-displacement curves were continuously monitored while loading half of the specimens in the oclluso-gingival direction and half in the mesio-distal direction. The stiffness was calculated from the linear portion of the curve. The mesio-distal direction was 31% stiffer than the occluso-gingival direction. The basal bone was 40% stiffer than the alveolar bone. The posterior zone was 46% stiffer than the anterior zone. The lingual aspect was stiffer than the buccal aspect. Although bone specimens do not behave as brittle materials, the diametral compression test can be adequately used for determining tensile behavior when only small bone specimens can be obtained. In conclusion, to obtain maximal orthodontic mini implant stability, the force components on the implants should be oriented mostly in the mesio-distal direction.

  13. Early detection of AD using cortical thickness measurements

    Science.gov (United States)

    Spjuth, M.; Gravesen, F.; Eskildsen, S. F.; Østergaard, L. R.

    2007-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder that causes cortical atrophy and impaired cognitive functions. The diagnosis is difficult to make and is often made over a longer period of time using a combination of neuropsychological tests, and structural and functional imaging. Due to the impact of early intervention the challenge of distinguishing early AD from normal ageing has received increasing attention. This study uses cortical thickness measurements to characterize the atrophy in nine mild AD patients (mean MMSE-score 23.3 (std: 2.6)) compared to five healthy middle-aged subjects. A fully automated method based on deformable models is used for delineation of the inner and outer boundaries of the cerebral cortex from Magnetic Resonance Images. This allows observer independent high-resolution quantification of the cortical thickness. The cortex analysis facilitates detection of alterations throughout the entire cortical mantle. To perform inter-subject thickness comparison in which the spatial information is retained, a feature-based registration algorithm is developed which uses local cortical curvature, normal vector, and a distance measure. A comparison of the two study groups reveals that the lateral side of the hemispheres shows diffuse thinner areas in the mild AD group but especially the medial side shows a pronounced thinner area which can be explained by early limbic changes in AD. For classification principal component analysis is applied to reduce the high number of thickness measurements (>200,000) into fewer features. All mild AD and healthy middle-aged subjects are classified correctly (sensitivity and specificity 100%).

  14. Impact of lanthanum carbonate on cortical bone in dialysis patients with adynamic bone disease.

    Science.gov (United States)

    Yajima, Aiji; Inaba, Masaaki; Tominaga, Yoshihiro; Tanaka, Motoko; Otsubo, Shigeru; Nitta, Kosaku; Ito, Akemi; Satoh, Shigeru

    2013-04-01

    Among the most serious problems in patients with chronic kidney disease (CKD) is fragility of cortical bone caused by cortical thinning and increased cortical porosity; the cortical fragility is sometimes irreversible, with fractures generally initiating from cortical bone. Therefore, development of treatments for problems of cortical bone is urgently desired. Cortical bone has the three surfaces, including the periosteal surface, intracortical spaces and endocortical surface. Bone turnover at the endocortical surface and intracortical resorption spaces are increased as compared with that at cancellous surface. Bone growth sometimes depends on apposition at the periosteal surface. We treated hyperphosphatemia in two hemodialysis patients with adynamic bone disease with 750-1500 mg/day of lanthanum carbonate, which is a non-calcium containing phosphate binder; the treatment resulted in a decrease of the serum phosphorus levels (P levels), without significant change of the serum intact parathyroid hormone levels. We now report that treatment of these patients with lanthanum carbonate increased mineralization of the periosteal surface, increased bone mass within the intracortical resorption spaces and increased mineralization of the minimodeling surface at the endocortical surface. In addition, woven bone volume in cortical bone was decreased and mineralization of bone units, namely, osteons, was increased. Although these findings were not observed across all surfaces of the cortical bone in the patients, it is expected that lanthanum carbonate would increase the cortical stability in CKD patients, with consequent reduction in the fracture rate in these patients.

  15. Extraction of the cerebral cortical boundaries from MRI for measurement of cortical thickness

    Science.gov (United States)

    Eskildsen, Simon F.; Uldahl, Mark; Ostergaard, Lasse R.

    2005-04-01

    Several neurodegenerative diseases, such as Alzheimer's disease, cause atrophy of the cerebral cortex. Measurements of cerebral cortical thickness and volume are used in the quantification and localization of atrophy. It is possible to measure the thickness of the cerebral cortex manually from magnetic resonance imaging, but partial volume effects, orthogonality problems, large amounts of manual labor and operator bias makes it difficult to conduct measurements on large patient populations. Automatic quantification and localization of atrophy is a highly desirable goal, as it facilitates the study of early anatomical changes and track disease progression on large populations. The first step in achieving this goal is to develop robust and accurate methods for measuring cortical thickness and volume automatically. We have developed a new method, capable of both extracting surface representations of the cortical boundaries from magnetic resonance imaging and measuring the cortical thickness. Experiments show that the developed method is robust and performs well on datasets of both healthy subjects and subjects suffering from Alzheimer's disease.

  16. Intelligence and cortical thickness in children with complex partial seizures.

    Science.gov (United States)

    Tosun, Duygu; Caplan, Rochelle; Siddarth, Prabha; Seidenberg, Michael; Gurbani, Suresh; Toga, Arthur W; Hermann, Bruce

    2011-07-15

    Prior studies on healthy children have demonstrated regional variations and a complex and dynamic relationship between intelligence and cerebral tissue. Yet, there is little information regarding the neuroanatomical correlates of general intelligence in children with epilepsy compared to healthy controls. In vivo imaging techniques, combined with methods for advanced image processing and analysis, offer the potential to examine quantitative mapping of brain development and its abnormalities in childhood epilepsy. A surface-based, computational high resolution 3-D magnetic resonance image analytic technique was used to compare the relationship of cortical thickness with age and intelligence quotient (IQ) in 65 children and adolescents with complex partial seizures (CPS) and 58 healthy controls, aged 6-18 years. Children were grouped according to health status (epilepsy; controls) and IQ level (average and above; below average) and compared on age-related patterns of cortical thickness. Our cross-sectional findings suggest that disruption in normal age-related cortical thickness expression is associated with intelligence in pediatric CPS patients both with average and below average IQ scores. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Cortical thickness abnormalities associated with dyslexia, independent of remediation status.

    Science.gov (United States)

    Ma, Yizhou; Koyama, Maki S; Milham, Michael P; Castellanos, F Xavier; Quinn, Brian T; Pardoe, Heath; Wang, Xiuyuan; Kuzniecky, Ruben; Devinsky, Orrin; Thesen, Thomas; Blackmon, Karen

    2015-01-01

    Abnormalities in cortical structure are commonly observed in children with dyslexia in key regions of the "reading network." Whether alteration in cortical features reflects pathology inherent to dyslexia or environmental influence (e.g., impoverished reading experience) remains unclear. To address this question, we compared MRI-derived metrics of cortical thickness (CT), surface area (SA), gray matter volume (GMV), and their lateralization across three different groups of children with a historical diagnosis of dyslexia, who varied in current reading level. We compared three dyslexia subgroups with: (1) persistent reading and spelling impairment; (2) remediated reading impairment (normal reading scores), and (3) remediated reading and spelling impairments (normal reading and spelling scores); and a control group of (4) typically developing children. All groups were matched for age, gender, handedness, and IQ. We hypothesized that the dyslexia group would show cortical abnormalities in regions of the reading network relative to controls, irrespective of remediation status. Such a finding would support that cortical abnormalities are inherent to dyslexia and are not a consequence of abnormal reading experience. Results revealed increased CT of the left fusiform gyrus in the dyslexia group relative to controls. Similarly, the dyslexia group showed CT increase of the right superior temporal gyrus, extending into the planum temporale, which resulted in a rightward CT asymmetry on lateralization indices. There were no group differences in SA, GMV, or their lateralization. These findings held true regardless of remediation status. Each reading level group showed the same "double hit" of atypically increased left fusiform CT and rightward superior temporal CT asymmetry. Thus, findings provide evidence that a developmental history of dyslexia is associated with CT abnormalities, independent of remediation status.

  18. Cortical thickness abnormalities associated with dyslexia, independent of remediation status

    Directory of Open Access Journals (Sweden)

    Yizhou Ma

    2015-01-01

    Full Text Available Abnormalities in cortical structure are commonly observed in children with dyslexia in key regions of the “reading network.” Whether alteration in cortical features reflects pathology inherent to dyslexia or environmental influence (e.g., impoverished reading experience remains unclear. To address this question, we compared MRI-derived metrics of cortical thickness (CT, surface area (SA, gray matter volume (GMV, and their lateralization across three different groups of children with a historical diagnosis of dyslexia, who varied in current reading level. We compared three dyslexia subgroups with: (1 persistent reading and spelling impairment; (2 remediated reading impairment (normal reading scores, and (3 remediated reading and spelling impairments (normal reading and spelling scores; and a control group of (4 typically developing children. All groups were matched for age, gender, handedness, and IQ. We hypothesized that the dyslexia group would show cortical abnormalities in regions of the reading network relative to controls, irrespective of remediation status. Such a finding would support that cortical abnormalities are inherent to dyslexia and are not a consequence of abnormal reading experience. Results revealed increased CT of the left fusiform gyrus in the dyslexia group relative to controls. Similarly, the dyslexia group showed CT increase of the right superior temporal gyrus, extending into the planum temporale, which resulted in a rightward CT asymmetry on lateralization indices. There were no group differences in SA, GMV, or their lateralization. These findings held true regardless of remediation status. Each reading level group showed the same “double hit” of atypically increased left fusiform CT and rightward superior temporal CT asymmetry. Thus, findings provide evidence that a developmental history of dyslexia is associated with CT abnormalities, independent of remediation status.

  19. Cortical thickness abnormalities associated with dyslexia, independent of remediation status

    Science.gov (United States)

    Ma, Yizhou; Koyama, Maki S.; Milham, Michael P.; Castellanos, F. Xavier; Quinn, Brian T.; Pardoe, Heath; Wang, Xiuyuan; Kuzniecky, Ruben; Devinsky, Orrin; Thesen, Thomas; Blackmon, Karen

    2014-01-01

    Abnormalities in cortical structure are commonly observed in children with dyslexia in key regions of the “reading network.” Whether alteration in cortical features reflects pathology inherent to dyslexia or environmental influence (e.g., impoverished reading experience) remains unclear. To address this question, we compared MRI-derived metrics of cortical thickness (CT), surface area (SA), gray matter volume (GMV), and their lateralization across three different groups of children with a historical diagnosis of dyslexia, who varied in current reading level. We compared three dyslexia subgroups with: (1) persistent reading and spelling impairment; (2) remediated reading impairment (normal reading scores), and (3) remediated reading and spelling impairments (normal reading and spelling scores); and a control group of (4) typically developing children. All groups were matched for age, gender, handedness, and IQ. We hypothesized that the dyslexia group would show cortical abnormalities in regions of the reading network relative to controls, irrespective of remediation status. Such a finding would support that cortical abnormalities are inherent to dyslexia and are not a consequence of abnormal reading experience. Results revealed increased CT of the left fusiform gyrus in the dyslexia group relative to controls. Similarly, the dyslexia group showed CT increase of the right superior temporal gyrus, extending into the planum temporale, which resulted in a rightward CT asymmetry on lateralization indices. There were no group differences in SA, GMV, or their lateralization. These findings held true regardless of remediation status. Each reading level group showed the same “double hit” of atypically increased left fusiform CT and rightward superior temporal CT asymmetry. Thus, findings provide evidence that a developmental history of dyslexia is associated with CT abnormalities, independent of remediation status. PMID:25610779

  20. Female Mice Lacking Estrogen Receptor-α in Hypothalamic Proopiomelanocortin (POMC) Neurons Display Enhanced Estrogenic Response on Cortical Bone Mass.

    Science.gov (United States)

    Farman, H H; Windahl, S H; Westberg, L; Isaksson, H; Egecioglu, E; Schele, E; Ryberg, H; Jansson, J O; Tuukkanen, J; Koskela, A; Xie, S K; Hahner, L; Zehr, J; Clegg, D J; Lagerquist, M K; Ohlsson, C

    2016-08-01

    Estrogens are important regulators of bone mass and their effects are mainly mediated via estrogen receptor (ER)α. Central ERα exerts an inhibitory role on bone mass. ERα is highly expressed in the arcuate (ARC) and the ventromedial (VMN) nuclei in the hypothalamus. To test whether ERα in proopiomelanocortin (POMC) neurons, located in ARC, is involved in the regulation of bone mass, we used mice lacking ERα expression specifically in POMC neurons (POMC-ERα(-/-)). Female POMC-ERα(-/-) and control mice were ovariectomized (OVX) and treated with vehicle or estradiol (0.5 μg/d) for 6 weeks. As expected, estradiol treatment increased the cortical bone thickness in femur, the cortical bone mechanical strength in tibia and the trabecular bone volume fraction in both femur and vertebrae in OVX control mice. Importantly, the estrogenic responses were substantially increased in OVX POMC-ERα(-/-) mice compared with the estrogenic responses in OVX control mice for cortical bone thickness (+126 ± 34%, P mass, ERα was silenced using an adeno-associated viral vector. Silencing of ERα in hypothalamic VMN resulted in unchanged bone mass. In conclusion, mice lacking ERα in POMC neurons display enhanced estrogenic response on cortical bone mass and mechanical strength. We propose that the balance between inhibitory effects of central ERα activity in hypothalamic POMC neurons in ARC and stimulatory peripheral ERα-mediated effects in bone determines cortical bone mass in female mice.

  1. Basic visual function and cortical thickness patterns in posterior cortical atrophy.

    Science.gov (United States)

    Lehmann, Manja; Barnes, Josephine; Ridgway, Gerard R; Wattam-Bell, John; Warrington, Elizabeth K; Fox, Nick C; Crutch, Sebastian J

    2011-09-01

    Posterior cortical atrophy (PCA) is characterized by a progressive decline in higher-visual object and space processing, but the extent to which these deficits are underpinned by basic visual impairments is unknown. This study aimed to assess basic and higher-order visual deficits in 21 PCA patients. Basic visual skills including form detection and discrimination, color discrimination, motion coherence, and point localization were measured, and associations and dissociations between specific basic visual functions and measures of higher-order object and space perception were identified. All participants showed impairment in at least one aspect of basic visual processing. However, a number of dissociations between basic visual skills indicated a heterogeneous pattern of visual impairment among the PCA patients. Furthermore, basic visual impairments were associated with particular higher-order object and space perception deficits, but not with nonvisual parietal tasks, suggesting the specific involvement of visual networks in PCA. Cortical thickness analysis revealed trends toward lower cortical thickness in occipitotemporal (ventral) and occipitoparietal (dorsal) regions in patients with visuoperceptual and visuospatial deficits, respectively. However, there was also a lot of overlap in their patterns of cortical thinning. These findings suggest that different presentations of PCA represent points in a continuum of phenotypical variation.

  2. The Effects of Obesity on Murine Cortical Bone

    Science.gov (United States)

    Martin, Sophi

    This dissertation details the effects of obesity on the mechanical properties and structure of cortical bone. Obesity is associated with greater bone mineral content that might be expected to protect against fracture, which has been observed in adults. Paradoxically however, the incidence of bone fractures has been found to increase in overweight and obese children and adolescents. Femora from adolescent and adult mice fed a high-fat diet are investigated for changes in shape, tissue structure, as well as tissue-level and whole-bone mechanical properties. Results indicate increased bone size, reduced size-independent mechanical properties, but maintained size-dependent mechanical properties. Other changes in cortical bone response to obesity are observed with advancing age. This study indicates that bone quantity and bone quality play important compensatory roles in determining fracture risk, and that fracture risk may not be lessened for adults as previously thought.

  3. Lumbar pedicle cortical bone trajectory screw

    Institute of Scientific and Technical Information of China (English)

    Song Tengfei; Wellington K Hsu; Ye Tianwen

    2014-01-01

    Objective The purpose of this study was to demonstrate the lumbar pedicle cortical bone trajectory (CBT) screw fixation technique,a new fixation technique for lumbar surgery.Data sources The data analyzed in this review are mainly from articles reported in PubMed published from 1994 to 2014.Study selection Original articles and critical reviews relevant to CBT technique and lumbar pedicle fixation were selected.Results CBT technique was firstly introduced as a new fixation method for lumbar pedicle surgery in 2009.The concepts,morphometric study,biomechanical characteristics and clinical applications of CBT technique were reviewed.The insertional point of CBT screw is located at the lateral point of the pars interarticularis,and its trajectory follows a caudocephalad path sagittally and a laterally directed path in the transverse plane.CBT technique can be used for posterior fixation during lumbar fusion procedures.This technique is a minimally invasive surgery,which affords better biomechanical stability,fixation strength and surgical safety.Therefore,CBT technique has the greatest benefit in lumbar pedicle surgery for patients with osteoporosis and obesity.Conclusion CBT technique is a better alternative option of lumbar pedicle fixation,especially for patients with osteoporosis and obesity.

  4. Genetic algorithms-based inversion of multimode guided waves for cortical bone characterization

    Science.gov (United States)

    Bochud, N.; Vallet, Q.; Bala, Y.; Follet, H.; Minonzio, J.-G.; Laugier, P.

    2016-10-01

    Recent progress in quantitative ultrasound has exploited the multimode waveguide response of long bones. Measurements of the guided modes, along with suitable waveguide modeling, have the potential to infer strength-related factors such as stiffness (mainly determined by cortical porosity) and cortical thickness. However, the development of such model-based approaches is challenging, in particular because of the multiparametric nature of the inverse problem. Current estimation methods in the bone field rely on a number of assumptions for pairing the incomplete experimental data with the theoretical guided modes (e.g. semi-automatic selection and classification of the data). The availability of an alternative inversion scheme that is user-independent is highly desirable. Thus, this paper introduces an efficient inversion method based on genetic algorithms using multimode guided waves, in which the mode-order is kept blind. Prior to its evaluation on bone, our proposal is validated using laboratory-controlled measurements on isotropic plates and bone-mimicking phantoms. The results show that the model parameters (i.e. cortical thickness and porosity) estimated from measurements on a few ex vivo human radii are in good agreement with the reference values derived from x-ray micro-computed tomography. Further, the cortical thickness estimated from in vivo measurements at the third from the distal end of the radius is in good agreement with the values delivered by site-matched high-resolution x-ray peripheral computed tomography.

  5. Risk Factors and Consequences of Cortical Thickness in an Asian Population

    NARCIS (Netherlands)

    Hilal, S.; Xin, X.; Ang, S.L.; Tan, C.S.; Venketasubramanian, N.; Niessen, W.J.; Vrooman, H.; Wong, T.Y.; Chen, C.; Ikram, M.K.

    2015-01-01

    Cortical thickness has been suggested to be one of the most important markers of cortical atrophy. In this study, we examined potential risk factors of cortical thickness and its association with cognition in an elderly Asian population from Singapore. This is a cross-sectional study among 572 Chi

  6. Cortical and trabecular bone benefits of mechanical loading are maintained long-term in mice independent of ovariectomy

    Science.gov (United States)

    Warden, Stuart J.; Galley, Matthew R.; Hurd, Andrea L.; Richard, Jeffrey S.; George, Lydia A.; Guildenbecher, Elizabeth A.; Barker, Rick G.; Fuchs, Robyn K.

    2014-01-01

    Skeletal loading enhances cortical and trabecular bone properties. How long these benefits last following loading cessation remains an unresolved, clinically-relevant question. This study investigated long-term maintenance of loading-induced cortical and trabecular bone benefits in female C57BL/6 mice and the influence of a surgically-induced menopause on the maintenance. 16-week-old animals had their right tibia extrinsically loaded 3 days/week for 4 weeks using the mouse tibial axial compression loading model. Left tibias were not loaded and served as internal controls. Animals were subsequently detrained (restricted to cage activities) for 0, 4, 8, 26 or 52 weeks, with ovariectomy (OVX) or sham-OVX surgery being performed at 0 weeks detraining. Loading increased midshaft tibia cortical bone mass, size and strength, and proximal tibia bone volume fraction. The cortical bone mass, area and thickness benefits of loading were lost by 26 weeks of detraining due to heightened medullary expansion. However, loading-induced benefits on bone total area and strength were maintained at each detraining time point. Similarly, the benefits of loading on bone volume fraction persisted at all detraining time points. The long-term benefits of loading on both cortical and trabecular bone were not influenced by a surgically-induced menopause as there were no interactions between loading and surgery. However, OVX had independent effects on cortical bone properties at early (4 and 8 weeks) detraining time points and trabecular bone properties at all detraining time points. These cumulative data indicate loading has long-term benefits on cortical bone size and strength (but not mass) and trabecular bone morphology which are not influenced by a surgically-induced menopause. This suggests skeletal loading associated with physical activity may provide long-term benefits by preparing the skeleton to offset both the cortical and trabecular bone changes associated with aging and menopause

  7. Probiotics protect mice from ovariectomy-induced cortical bone loss.

    Science.gov (United States)

    Ohlsson, Claes; Engdahl, Cecilia; Fåk, Frida; Andersson, Annica; Windahl, Sara H; Farman, Helen H; Movérare-Skrtic, Sofia; Islander, Ulrika; Sjögren, Klara

    2014-01-01

    The gut microbiota (GM) modulates the hosts metabolism and immune system. Probiotic bacteria are defined as live microorganisms which when administered in adequate amounts confer a health benefit on the host and can alter the composition of the GM. Germ-free mice have increased bone mass associated with reduced bone resorption indicating that the GM also regulates bone mass. Ovariectomy (ovx) results in bone loss associated with altered immune status. The purpose of this study was to determine if probiotic treatment protects mice from ovx-induced bone loss. Mice were treated with either a single Lactobacillus (L) strain, L. paracasei DSM13434 (L. para) or a mixture of three strains, L. paracasei DSM13434, L. plantarum DSM 15312 and DSM 15313 (L. mix) given in the drinking water during 6 weeks, starting two weeks before ovx. Both the L. para and the L. mix treatment protected mice from ovx-induced cortical bone loss and bone resorption. Cortical bone mineral content was higher in both L. para and L. mix treated ovx mice compared to vehicle (veh) treated ovx mice. Serum levels of the resorption marker C-terminal telopeptides and the urinary fractional excretion of calcium were increased by ovx in the veh treated but not in the L. para or the L. mix treated mice. Probiotic treatment reduced the expression of the two inflammatory cytokines, TNFα and IL-1β, and increased the expression of OPG, a potent inhibitor of osteoclastogenesis, in cortical bone of ovx mice. In addition, ovx decreased the frequency of regulatory T cells in bone marrow of veh treated but not probiotic treated mice. In conclusion, treatment with L. para or the L. mix prevents ovx-induced cortical bone loss. Our findings indicate that these probiotic treatments alter the immune status in bone resulting in attenuated bone resorption in ovx mice.

  8. Probiotics protect mice from ovariectomy-induced cortical bone loss.

    Directory of Open Access Journals (Sweden)

    Claes Ohlsson

    Full Text Available The gut microbiota (GM modulates the hosts metabolism and immune system. Probiotic bacteria are defined as live microorganisms which when administered in adequate amounts confer a health benefit on the host and can alter the composition of the GM. Germ-free mice have increased bone mass associated with reduced bone resorption indicating that the GM also regulates bone mass. Ovariectomy (ovx results in bone loss associated with altered immune status. The purpose of this study was to determine if probiotic treatment protects mice from ovx-induced bone loss. Mice were treated with either a single Lactobacillus (L strain, L. paracasei DSM13434 (L. para or a mixture of three strains, L. paracasei DSM13434, L. plantarum DSM 15312 and DSM 15313 (L. mix given in the drinking water during 6 weeks, starting two weeks before ovx. Both the L. para and the L. mix treatment protected mice from ovx-induced cortical bone loss and bone resorption. Cortical bone mineral content was higher in both L. para and L. mix treated ovx mice compared to vehicle (veh treated ovx mice. Serum levels of the resorption marker C-terminal telopeptides and the urinary fractional excretion of calcium were increased by ovx in the veh treated but not in the L. para or the L. mix treated mice. Probiotic treatment reduced the expression of the two inflammatory cytokines, TNFα and IL-1β, and increased the expression of OPG, a potent inhibitor of osteoclastogenesis, in cortical bone of ovx mice. In addition, ovx decreased the frequency of regulatory T cells in bone marrow of veh treated but not probiotic treated mice. In conclusion, treatment with L. para or the L. mix prevents ovx-induced cortical bone loss. Our findings indicate that these probiotic treatments alter the immune status in bone resulting in attenuated bone resorption in ovx mice.

  9. Strontium Ranelate Effect on the Repair of Bone Defects and Molecular Components of the Cortical Bone of Rats.

    Science.gov (United States)

    Rosa, Jucely Aparecida da; Sakane, Kumiko Koibuchi; Santos, Karina Cecília Panelli; Corrêa, Vivian Bradaschia; Arana-Chavez, Victor Elias; Oliveira, Jefferson Xavier de

    2016-01-01

    This study was conducted to evaluate the effects of treatment with strontium ranelate (SR) on the repair of bone defects and molecular components of bones in femurs. Adult female rats (n=27) were subjected to ovariectomy (OVX) or Sham surgery. Thirty days after surgery, a defect was made in the femur and the animals were then divided into three groups: OVX, SHAM and OVX+SR. Euthanasia was performed four weeks after the bone defect surgery. Repair in bone defect was assessed by computed microtomography (μCT) and chemical composition of cortical bone was analyzed by Fourier transform infrared (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDS). The trabecular thickness (Tb.Th) of the newly formed bone in the OVX+SR group was significantly higher than that for the OVX group. The collagen maturity in the OVX+SR group was smaller than in the other two groups. In this group, a significant increase in the amount of strontium (Sr) and a decrease in the amount of calcium (Ca) embedded to bone tissue were also observed. Systemic treatment with SR improved microarchitecture of the newly formed bone inside the defect, but decreased cross-linking of mature collagen in cortical bone.

  10. Cortical thickness and behavior abnormalities in children born preterm.

    Directory of Open Access Journals (Sweden)

    Leire Zubiaurre-Elorza

    Full Text Available AIM: To identify long-term effects of preterm birth and of periventricular leukomalacia (PVL on cortical thickness (CTh. To study the relationship between CTh and cognitive-behavioral abnormalities. METHODS: We performed brain magnetic resonance imaging on 22 preterm children with PVL, 14 preterm children with no evidence of PVL and 22 full-term peers. T1-weighted images were analyzed with FreeSurfer software. All participants underwent cognitive and behavioral assessments by means of the Wechsler Intelligence Scales for Children-Fourth Edition (WISC-IV and the Child Behavior Checklist (CBCL. RESULTS: We did not find global CTh differences between the groups. However, a thinner cortex was found in left postcentral, supramarginal, and caudal middle rostral gyri in preterm children with no evidence of PVL than in the full-term controls, while PVL preterm children showed thicker cortex in right pericalcarine and left rostral middle frontal areas than in preterm children with no evidence of PVL. In the PVL group, internalizing and externalizing scores correlated mainly with CTh in frontal areas. Attentional scores were found to be higher in PVL and correlated with CTh increments in right frontal areas. INTERPRETATION: The preterm group with no evidence of PVL, when compared with full-term children, showed evidence of a different pattern of regional thinning in the cortical gray matter. In turn, PVL preterm children exhibited atypical increases in CTh that may underlie their prevalent behavioral problems.

  11. Sexual orientation related differences in cortical thickness in male individuals.

    Directory of Open Access Journals (Sweden)

    Christoph Abé

    Full Text Available Previous neuroimaging studies demonstrated sex and also sexual orientation related structural and functional differences in the human brain. Genetic information and effects of sex hormones are assumed to contribute to the male/female differentiation of the brain, and similar effects could play a role in processes influencing human's sexual orientation. However, questions about the origin and development of a person's sexual orientation remain unanswered, and research on sexual orientation related neurobiological characteristics is still very limited. To contribute to a better understanding of the neurobiology of sexual orientation, we used magnetic resonance imaging (MRI in order to compare regional cortical thickness (Cth and subcortical volumes of homosexual men (hoM, heterosexual men (heM and heterosexual women (heW. hoM (and heW had thinner cortices primarily in visual areas and smaller thalamus volumes than heM, in which hoM and heW did not differ. Our results support previous studies, which suggest cerebral differences between hoM and heM in regions, where sex differences have been reported, which are frequently proposed to underlie biological mechanisms. Thus, our results contribute to a better understanding of the neurobiology of sexual orientation.

  12. Sexual orientation related differences in cortical thickness in male individuals.

    Science.gov (United States)

    Abé, Christoph; Johansson, Emilia; Allzén, Elin; Savic, Ivanka

    2014-01-01

    Previous neuroimaging studies demonstrated sex and also sexual orientation related structural and functional differences in the human brain. Genetic information and effects of sex hormones are assumed to contribute to the male/female differentiation of the brain, and similar effects could play a role in processes influencing human's sexual orientation. However, questions about the origin and development of a person's sexual orientation remain unanswered, and research on sexual orientation related neurobiological characteristics is still very limited. To contribute to a better understanding of the neurobiology of sexual orientation, we used magnetic resonance imaging (MRI) in order to compare regional cortical thickness (Cth) and subcortical volumes of homosexual men (hoM), heterosexual men (heM) and heterosexual women (heW). hoM (and heW) had thinner cortices primarily in visual areas and smaller thalamus volumes than heM, in which hoM and heW did not differ. Our results support previous studies, which suggest cerebral differences between hoM and heM in regions, where sex differences have been reported, which are frequently proposed to underlie biological mechanisms. Thus, our results contribute to a better understanding of the neurobiology of sexual orientation.

  13. Apathy is associated with lower inferior temporal cortical thickness in mild cognitive impairment and normal elderly

    Science.gov (United States)

    Guercio, Brendan; Donovan, Nancy J.; Ward, Andrew; Schultz, Aaron; Lorius, Natacha; Amariglio, Rebecca E.; Rentz, Dorene M.; Johnson, Keith A.; Sperling, Reisa A.; Marshall, Gad A.

    2014-01-01

    Apathy is a common neuropsychiatric symptom in Alzheimer’s disease (AD) dementia and amnestic mild cognitive impairment (MCI) and is associated with cortical atrophy in AD dementia. This study investigated possible correlations between apathy and cortical atrophy in 47 individuals with MCI and 19 clinically normal elderly (CN). Backward elimination multivariate linear regression was used to evaluate the cross-sectional relationship between scores on the Apathy Evaluation Scale and thickness of several cortical regions and covariates. Lower inferior temporal cortical thickness was predictive of greater apathy. Greater anterior cingulate cortical thickness was also predictive of greater apathy, suggesting an underlying reactive process. PMID:25716491

  14. Extra-nuclear effects of estrogen on cortical bone in males require ERαAF-1

    Science.gov (United States)

    Wu, J; Gustafsson, K L; Windahl, S H; Kim, S H; Katzenellenbogen, J A; Ohlsson, C; Lagerquist, M K

    2017-01-01

    Estradiol (E2) signaling via estrogen receptor alpha (ERα) is important for the male skeleton as demonstrated by ERα inactivation in both mice and man. ERα mediates estrogenic effects not only by translocating to the nucleus and affecting gene transcription but also by extra-nuclear actions e.g., triggering cytoplasmic signaling cascades. ERα contains various domains, and the role of activation function 1 (ERαAF-1) is known to be tissue specific. The aim of this study was to determine the importance of extra-nuclear estrogen effects for the skeleton in males and to determine the role of ERαAF-1 for mediating these effects. Five-month-old male wild-type (WT) and ERαAF-1-inactivated (ERαAF-10) mice were orchidectomized and treated with equimolar doses of 17β-estradiol (E2) or an estrogen dendrimer conjugate (EDC), which is incapable of entering the nucleus and thereby only initiates extra-nuclear ER actions or their corresponding vehicles for 3.5 weeks. As expected, E2 treatment increased cortical thickness and trabecular bone volume per total volume (BV/TV) in WT males. EDC treatment increased cortical thickness in WT males, whereas no effect was detected in trabecular bone. In ERαAF-10 males, E2 treatment increased cortical thickness, but did not affect trabecular bone. Interestingly, the effect of EDC on cortical bone was abolished in ERαAF-10 mice. In conclusion, extra-nuclear estrogen signaling affects cortical bone mass in males, and this effect is dependent on a functional ERαAF-1. Increased knowledge regarding estrogen signaling mechanisms in the regulation of the male skeleton may aid the development of new treatment options for male osteoporosis. PMID:28057769

  15. Calorie restriction aggravated cortical and trabecular bone architecture in ovariectomy-induced estrogen-deficient rats.

    Science.gov (United States)

    Ahn, Hyejin; Seo, Dong-Hyun; Kim, Han Sung; Choue, Ryowon

    2014-08-01

    We hypothesized that calorie restriction (CR) and estrogen deficiency (ovariectomy [OVX]) would aggravate bone biomarkers and structural parameters in rats. Seven-week-old female Sprague-Dawley rats were randomized to sham-operated groups and fed either an ad libitum diet (SHAM-AL) or a CR diet (SHAM-CR); ovariectomy-operated groups were fed an ad libitum diet (OVX-AL) or a CR diet (OVX-CR). For 8 weeks, the OVX-AL and SHAM-AL groups were fed the same diet, whereas CR groups were fed a diet containing 50% fewer calories. Bone-related biomarkers and structural parameters (OC; deoxypyridinoline [DPD]; N-terminal telopeptide, NTx; architecture and mineralization; and microcomputed tomography images) were analyzed at the end of the experiment. The serum OC levels of calorie-restricted groups (SHAM-CR and OVX-CR) were significantly lower than those of the AL groups (SHAM-AL and OVX-AL) (P bone, the calorie-restricted and ovariectomized groups had lower values of bone volume to total volume, trabecular number, and bone mineral density, but higher values of trabecular separation than those of their counterparts (P bone, the calorie-restricted groups had reduced values of bone volume, mean polar moment of inertia, and cortical thickness compared to the AL groups (P bone; CR has detrimental effects on trabecular and cortical bone; and estrogen deficiency only had an effect on trabecular bone. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Brain cortical thickness in male adolescents with serious substance use and conduct problems

    Science.gov (United States)

    Chumachenko, Serhiy Y.; Sakai, Joseph T.; Dalwani, Manish S.; Mikulich-Gilbertson, Susan K.; Dunn, Robin; Tanabe, Jody; Young, Susan; McWilliams, Shannon K.; Banich, Marie T.; Crowley, Thomas J.

    2016-01-01

    Background Adolescents with substance use disorder (SUD) and conduct problems exhibit high levels of impulsivity and poor self-control. Limited work to date tests for brain cortical thickness differences in these youths. Objectives To investigate differences in cortical thickness between adolescents with substance use and conduct problems and controls. Methods We recruited 25 male adolescents with SUD, and 19 male adolescent controls, and completed structural 3T magnetic resonance brain imaging. Using the surface-based morphometry software FreeSurfer, we completed region-of-interest (ROI) analyses for group cortical thickness differences in left, and separately right, inferior frontal gyrus (IFG), orbitofrontal cortex (OFC) and insula. Using FreeSurfer, we completed whole-cerebrum analyses of group differences in cortical thickness. Results Versus controls, the SUD group showed no cortical thickness differences in ROI analyses. Controlling for age and IQ, no regions with cortical thickness differences were found using whole-cerebrum analyses (though secondary analyses co-varying IQ and whole-cerebrum cortical thickness yielded a between-group cortical thickness difference in the left posterior cingulate/precuneus). Secondary findings showed that the SUD group, relative to controls, demonstrated significantly less right>left asymmetry in IFG, had weaker insular-to-whole-cerebrum cortical thickness correlations, and showed a positive association between conduct disorder symptom count and cortical thickness in a superior temporal gyrus cluster. Conclusion Functional group differences may reflect a more nuanced cortical morphometric difference than ROI cortical thickness. Further investigation of morphometric differences is needed. If replicable findings can be established, they may aid in developing improved diagnostic or more targeted treatment approaches. PMID:26337200

  17. Brain cortical thickness in male adolescents with serious substance use and conduct problems.

    Science.gov (United States)

    Chumachenko, Serhiy Y; Sakai, Joseph T; Dalwani, Manish S; Mikulich-Gilbertson, Susan K; Dunn, Robin; Tanabe, Jody; Young, Susan; McWilliams, Shannon K; Banich, Marie T; Crowley, Thomas J

    2015-01-01

    Adolescents with substance use disorder (SUD) and conduct problems exhibit high levels of impulsivity and poor self-control. Limited work to date tests for brain cortical thickness differences in these youths. To investigate differences in cortical thickness between adolescents with substance use and conduct problems and controls. We recruited 25 male adolescents with SUD, and 19 male adolescent controls, and completed structural 3T magnetic resonance brain imaging. Using the surface-based morphometry software FreeSurfer, we completed region-of-interest (ROI) analyses for group cortical thickness differences in left, and separately right, inferior frontal gyrus (IFG), orbitofrontal cortex (OFC) and insula. Using FreeSurfer, we completed whole-cerebrum analyses of group differences in cortical thickness. Versus controls, the SUD group showed no cortical thickness differences in ROI analyses. Controlling for age and IQ, no regions with cortical thickness differences were found using whole-cerebrum analyses (though secondary analyses co-varying IQ and whole-cerebrum cortical thickness yielded a between-group cortical thickness difference in the left posterior cingulate/precuneus). Secondary findings showed that the SUD group, relative to controls, demonstrated significantly less right > left asymmetry in IFG, had weaker insular-to-whole-cerebrum cortical thickness correlations, and showed a positive association between conduct disorder symptom count and cortical thickness in a superior temporal gyrus cluster. Functional group differences may reflect a more nuanced cortical morphometric difference than ROI cortical thickness. Further investigation of morphometric differences is needed. If replicable findings can be established, they may aid in developing improved diagnostic or more targeted treatment approaches.

  18. Regional variability in secondary remodeling within long bone cortices of catarrhine primates: the influence of bone growth history.

    Science.gov (United States)

    McFarlin, Shannon C; Terranova, Carl J; Zihlman, Adrienne L; Enlow, Donald H; Bromage, Timothy G

    2008-09-01

    Secondary intracortical remodeling of bone varies considerably among and within vertebrate skeletons. Although prior research has shed important light on its biomechanical significance, factors accounting for this variability remain poorly understood. We examined regional patterning of secondary osteonal bone in an ontogenetic series of wild-collected primates, at the midshaft femur and humerus of Chlorocebus (Cercopithecus) aethiops (n = 32) and Hylobates lar (n = 28), and the midshaft femur of Pan troglodytes (n = 12). Our major objectives were: 1) to determine whether secondary osteonal bone exhibits significant regional patterning across inner, mid-cortical and outer circumferential cortical rings within cross-sections; and if so, 2) to consider the manner in which this regional patterning may reflect the influence of relative tissue age and other circumstances of bone growth. Using same field-of-view images of 100-microm-thick cross-sections acquired in brightfield and circularly polarized light microscopy, we quantified the percent area of secondary osteonal bone (%HAV) for whole cross-sections and across the three circumferential rings within cross-sections. We expected bone areas with inner and middle rings to exhibit higher %HAV than the outer cortical ring within cross-sections, the latter comprising tissues of more recent depositional history. Observations of primary bone microstructural development provided an additional context in which to evaluate regional patterning of intracortical remodeling. Results demonstrated significant regional variability in %HAV within all skeletal sites. As predicted,%HAV was usually lowest in the outer cortical ring within cross-sections. However, regional patterning across inner vs. mid-cortical rings showed a more variable pattern across taxa, age classes, and skeletal sites examined. Observations of primary bone microstructure revealed that the distribution of endosteally deposited bone had an important influence on

  19. Associations between cortical thickness and general intelligence in children, adolescents and young adults

    NARCIS (Netherlands)

    K. Menary (Kyle); P.F. Collins (Paul); J.N. Porter (James); R.L. Muetzel (Ryan); E.A. Olson (Elizabeth); V. Kumar (Vipin); D. Steinbach; K.O. Lim (Kelvin); M. Luciana (Monica)

    2013-01-01

    textabstractNeuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed

  20. Associations between cortical thickness and general intelligence in children, adolescents and young adults

    NARCIS (Netherlands)

    K. Menary (Kyle); P.F. Collins (Paul); J.N. Porter (James); R.L. Muetzel (Ryan); E.A. Olson (Elizabeth); V. Kumar (Vipin); D. Steinbach; K.O. Lim (Kelvin); M. Luciana (Monica)

    2013-01-01

    textabstractNeuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed throug

  1. Disuse exaggerates the detrimental effects of alcohol on cortical bone

    Science.gov (United States)

    Hefferan, Theresa E.; Kennedy, Angela M.; Evans, Glenda L.; Turner, Russell T.

    2003-01-01

    BACKGROUND: Alcohol abuse is associated with an increased risk for osteoporosis. However, comorbidity factors may play an important role in the pathogenesis of alcohol-related bone fractures. Suboptimal mechanical loading of the skeleton, an established risk factor for bone loss, may occur in some alcohol abusers due to reduced physical activity, muscle atrophy, or both. The effect of alcohol consumption and reduced physical activity on bone metabolism has not been well studied. The purpose of this study was to determine whether mechanical disuse alters bone metabolism in a rat model for chronic alcohol abuse. METHODS: Alcohol was administered in the diet (35% caloric intake) of 6-month-old male rats for 4 weeks. Rats were hindlimb-unloaded the final 2 weeks of the experiment to prevent dynamic weight bearing. Afterward, cortical bone histomorphometry was evaluated at the tibia-fibula synostosis. RESULTS: At the periosteal surface of the tibial diaphysis, alcohol and hindlimb unloading independently decreased the mineralizing perimeter, mineral apposition rate, and bone formation rate. In addition, alcohol, but not hindlimb unloading, increased endocortical bone resorption. The respective detrimental effects of alcohol and hindlimb unloading to inhibit bone formation were additive; there was no interaction between the two variables. CONCLUSIONS: Reduced weight bearing accentuates the detrimental effects of alcohol on cortical bone in adult male rats by further inhibiting bone formation. This finding suggests that reduced physical activity may be a comorbidity factor for osteoporosis in alcohol abusers.

  2. Architecture and microstructure of cortical bone in reconstructed canine mandibles after bone transport distraction osteogenesis.

    Science.gov (United States)

    Zapata, Uriel; Halvachs, Emily K; Dechow, Paul C; Elsalanty, Mohammed E; Opperman, Lynne A

    2011-11-01

    Reconstruction of the canine mandible using bone transport distraction osteogenesis has been shown to be a suitable method for correcting segmental bone defects produced by cancer, gunshots, and trauma. Although the mechanical quality of the new regenerate cortical bone seems to be related to the mineralization process, several questions regarding the microstructural patterns of the new bony tissue remain unanswered. The purpose of this study was to quantify any microstructural differences that may exist between the regenerate and control cortical bone. Five adult American foxhound dogs underwent unilateral bone transport distraction of the mandible to repair bone defects of 30-35 mm. Animals were killed 12 weeks after the beginning of the consolidation period. Fourteen cylindrical cortical samples were extracted from the superior, medial, and inferior aspects of the lingual and buccal plates of the reconstructed aspect of the mandible, and 21 specimens were collected similarly from the contralateral aspect of the mandible. Specimens were evaluated using histomorphometric and micro-computed tomographic techniques to compare their microstructure. Except for differences in haversian canal area, histomorphometric analyses suggested no statistical differences in microstructure between regenerate and control cortical bone. Morphological evaluation suggested a consistent level of anisotropy, possibly related to the distraction vector. After 12 weeks' consolidation, bone created during bone transport distraction osteogenesis was comparable to native bone in microstructure, architecture, and mechanical properties. It is proposed that, after enough time, the properties of the regenerate bone will be identical to that of native bone.

  3. Hip cortical thickness assessment in postmenopausal women with osteoporosis and strontium ranelate effect on hip geometry.

    Science.gov (United States)

    Briot, Karine; Benhamou, Claude Laurent; Roux, Christian

    2012-01-01

    The aims of this study were to assess the relationship between hip geometry and the 5-yr risk of hip fractures in postmenopausal osteoporotic women and the effects of strontium ranelate on these parameters. Using the 5-yr data of a randomized placebo-controlled trial of strontium ranelate (Treatment of Peripheral Osteoporosis Study [TROPOS]), we reanalyzed the hip dual-energy X-ray absorptiometry scans to determine the role of hip geometry in the risk of hip fractures (placebo group, n=636) and to analyze the effects of strontium ranelate (n=483). The outcomes included the hip structure analysis (HSA) parameters: cross-sectional area (CSA), section modulus, cortical thickness, and buckling ratio, measured at femoral neck, intertrochanteric (IT) region, and proximal shaft. The geometric parameters associated with an increased risk of hip fracture over 5yr were IT CSA and femoral shaft cortical thickness independent of age and total-hip bone mineral density (BMD). Using Bonferroni adjustment, IT cortical thickness was associated with the risk of hip fracture. Over 5yr, significant decreases in some femoral dimensions of the placebo group contrast with significant increases in strontium ranelate group after adjustment for age and BMD. Using Bonferroni adjustment, differences between placebo and strontium ranelate groups were no longer significant after adjustment on 5-yr BMD changes. Some HSA parameters have predictive value for hip fracture risk in postmenopausal osteoporotic women. Strontium ranelate improves some HSA parameters, through the BMD increase. Copyright © 2012 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  4. Macrostructural brain changes in patients with longstanding type 1 diabetes mellitus - a cortical thickness analysis study

    DEFF Research Database (Denmark)

    Frøkjær, J B; Brock, C; Søfteland, E

    2013-01-01

    with longstanding (average 24.6 years) type 1 DM and 20 healthy controls were studied in a 3T magnetic resonance scanner. Using an automated surface based cortical segmentation method, cortical thickness was assessed in anatomical regions including total and lobe-wise grey and white matter volumes. Also.......03) and superior parietal gyrus (P=0.008) in patients. The cortical thickness of these regions was not associated with diabetes duration, age at diabetes onset or to HbA1c (all P>0.08). Patients with peripheral neuropathy showed reduced right postcentral gyrus cortical thickness compared to patients without...

  5. Cortical thickness and low insight into symptoms in enduring schizophrenia.

    Science.gov (United States)

    Emami, Seema; Guimond, Synthia; Mallar Chakravarty, M; Lepage, Martin

    2016-01-01

    Poor insight is a common, multidimensional phenomenon in patients with schizophrenia, associated with poorer outcomes and treatment non-adherence. Yet scant research has investigated the neuronal correlates of insight into symptoms (IS), a dimension of insight that may be particularly significant in enduring schizophrenia. Sixty-six patients with enduring schizophrenia (duration >4years) and 33 healthy controls completed MRI scanning and IQ, depression, and anxiety assessments. The Scale to Assess Insight-Expanded (SAI-E) measured insight into patients' four most prominent symptoms and patients were classified into two groups: low IS (0-2; n=33), and high IS (>2; n=33). We evaluated the association between cortical thickness (CT) and insight into symptoms using two methods: (1) a between-patients region-of-interest analysis in the insula, superior temporal gyrus (STG) and frontal lobe; and (2) a whole-brain exploratory regression between patient and controls. Brain regions were segmented using a neuroanatomical atlas and vertex-wise CT analyses were conducted with CIVET, covaried for age and sex. ROI analysis revealed thinner insula cortex in patients with low IS (pinsight-related differences in CT that has been previously unexplored in enduring schizophrenia.

  6. Acute hypothalamic suppression significantly affects trabecular bone but not cortical bone following recovery and ovariectomy surgery in a rat model

    Directory of Open Access Journals (Sweden)

    Vanessa R. Yingling

    2016-01-01

    RH-a group compared to C, a similar deficit in BV/TV was also measured following recovery and post-OVX. The trabecular number and thickness were lower in the GnRH-a group compared to control.Conclusion. These data suggest that following a transient delay in pubertal onset, trabecular bone volume was significantly lower and no restoration of bone volume occurred following recovery or post-OVX surgery. However, cortical bone strength was maintained through architectural adaptations in the cortical bone envelope. An increase in the polar moment of inertia offset increased bone resorption. The current data are the first to suppress trabecular bone during growth, and then add an OVX protocol at maturity. Trabecular bone and cortical bone differed in their response to hypothalamic suppression during development; trabecular bone was more sensitive to the negative effects of hypothalamic suppression.

  7. A grape-enriched diet increases bone calcium retention and cortical bone properties in ovariectomized rats.

    Science.gov (United States)

    Hohman, Emily E; Weaver, Connie M

    2015-02-01

    Grapes and their associated phytochemicals have been investigated for beneficial effects on cardiovascular health, cancer prevention, and other chronic diseases, but the effect of grape consumption on bone health has not been fully determined. We previously found short-term benefits of grape products on reducing bone turnover in ovariectomized rats. The objective of this study was to determine the long-term benefits of a grape-enriched diet on bone in ovariectomized rats. Rats were ovariectomized at 3 mo of age and were administered a single dose of (45)Ca to prelabel bones at 4 mo of age. After a 1-mo equilibration period, baseline urinary (45)Ca excretion was determined. Rats (n = 22/group) were then randomly assigned to a modified AIN93M diet containing 25% freeze-dried grape powder or to a control diet for 8 wk. Urinary (45)Ca excretion was monitored throughout the study to determine changes in bone (45)Ca retention. Calcium balance was assessed after 1 and 8 wk of consuming the experimental diets, and a calcium kinetic study was performed at 8 wk. After 8 wk, femurs were collected for micro-computed tomographic imaging, 3-point bending, and reference point indentation. Rats fed the grape-enriched diet had 44% greater net bone calcium retention than did rats fed the control diet. There were no differences in calcium balance due to diet at either week 1 or week 8, but there was a significant increase in net calcium absorption (10.6%) and retention (5.7%) from week 1 to week 8 in the grape-enriched diet group only. Grape-enriched diet-fed rats had 3% greater cortical thickness and 11% greater breaking strength. There were no differences in femur bone mineral density, trabecular microarchitecture, or reference point indentation variables due to diet. This study of ovariectomized rats indicates that the consumption of grape products may improve calcium utilization and suppress bone turnover, resulting in improvements in bone quality. © 2015 American Society for

  8. Regional cortical gray matter thickness differences associated with type 2 diabetes and major depression

    Science.gov (United States)

    Ajilore, Olusola; Narr, Katherine; Rosenthal, Jonah; Pham, Daniel; Hamilton, Liberty; Watari, Kecia; Elderkin-Thompson, Virginia; Darwin, Christine; Toga, Arthur; Kumar, Anand

    2010-01-01

    Objective The purpose of this study was to examine the effect of type 2 diabetes with major depression on cortical gray matter using magnetic resonance imaging and cortical pattern matching techniques. We hypothesized that diabetic subjects and depressed diabetic subjects would demonstrate decreased cortical gray matter thickness in prefrontal areas as compared to healthy control subjects. Methods Patients with type 2 diabetes (n=26) and patients diabetes and major depression (n=26) were compared with healthy controls (n=20). Gray matter thickness across the entire cortex was measured using cortical pattern matching methods. Results All subjects with diabetes demonstrated decreased cortical gray matter thickness in the left anterior cingulate region. Additionally, depressed diabetic subjects showed significant cortical gray matter decreases in bilateral prefrontal areas compared with healthy controls. Correlations between clinical variables and cortical gray matter thickness revealed a significant negative relationship with cerebrovascular risk factors across all three groups, most consistently in the left dorsomedial prefrontal cortex. A significant positive relationship between performance on attention and executive function tasks and cortical gray matter thickness predominately in left hemisphere regions was also seen across all subjects. Conclusion Depression and diabetes are associated with significant cortical gray matter thinning in medial prefrontal areas. PMID:20832254

  9. Associations between cortical thickness and general intelligence in children, adolescents and young adults

    Science.gov (United States)

    Menary, Kyle; Collins, Paul F.; Porter, James N.; Muetzel, Ryan; Olson, Elizabeth A.; Kumar, Vipin; Steinbach, Michael; Lim, Kelvin O.; Luciana, Monica

    2013-01-01

    Neuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed throughout both brain hemispheres. In this study, we performed a cortical thickness mapping analysis on data from 182 healthy typically developing males and females ages 9 to 24 years to identify correlates of general intelligence (g) scores. To determine if these correlates also mediate associations of specific cognitive abilities with cortical thickness, we regressed specific cognitive test scores on g scores and analyzed the residuals with respect to cortical thickness. The effect of age on the association between cortical thickness and intelligence was examined. We found a widely distributed pattern of positive associations between cortical thickness and g scores, as derived from the first unrotated principal factor of a factor analysis of Wechsler Abbreviated Scale of Intelligence (WASI) subtest scores. After WASI specific cognitive subtest scores were regressed on g factor scores, the residual score variances did not correlate significantly with cortical thickness in the full sample with age covaried. When participants were grouped at the age median, significant positive associations of cortical thickness were obtained in the older group for g-residualized scores on Block Design (a measure of visual-motor integrative processing) while significant negative associations of cortical thickness were observed in the younger group for g-residualized Vocabulary scores. These results regarding correlates of general intelligence are concordant with the existing literature, while the findings from younger versus older subgroups have implications for future research on brain structural correlates of specific cognitive abilities, as well as the cognitive domain specificity of behavioral

  10. Associations between cortical thickness and general intelligence in children, adolescents and young adults.

    Science.gov (United States)

    Menary, Kyle; Collins, Paul F; Porter, James N; Muetzel, Ryan; Olson, Elizabeth A; Kumar, Vipin; Steinbach, Michael; Lim, Kelvin O; Luciana, Monica

    2013-09-01

    Neuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed throughout both brain hemispheres. In this study, we performed a cortical thickness mapping analysis on data from 182 healthy typically developing males and females ages 9 to 24 years to identify correlates of general intelligence (g) scores. To determine if these correlates also mediate associations of specific cognitive abilities with cortical thickness, we regressed specific cognitive test scores on g scores and analyzed the residuals with respect to cortical thickness. The effect of age on the association between cortical thickness and intelligence was examined. We found a widely distributed pattern of positive associations between cortical thickness and g scores, as derived from the first unrotated principal factor of a factor analysis of Wechsler Abbreviated Scale of Intelligence (WASI) subtest scores. After WASI specific cognitive subtest scores were regressed on g factor scores, the residual score variances did not correlate significantly with cortical thickness in the full sample with age covaried. When participants were grouped at the age median, significant positive associations of cortical thickness were obtained in the older group for g-residualized scores on Block Design (a measure of visual-motor integrative processing) while significant negative associations of cortical thickness were observed in the younger group for g-residualized Vocabulary scores. These results regarding correlates of general intelligence are concordant with the existing literature, while the findings from younger versus older subgroups have implications for future research on brain structural correlates of specific cognitive abilities, as well as the cognitive domain specificity of behavioral

  11. Bone turnover markers are associated with higher cortical porosity, thinner cortices, and larger size of the proximal femur and non-vertebral fractures.

    Science.gov (United States)

    Shigdel, Rajesh; Osima, Marit; Ahmed, Luai A; Joakimsen, Ragnar M; Eriksen, Erik F; Zebaze, Roger; Bjørnerem, Åshild

    2015-12-01

    Bone turnover markers (BTM) predict bone loss and fragility fracture. Although cortical porosity and cortical thinning are important determinants of bone strength, the relationship between BTM and cortical porosity has, however, remained elusive. We therefore wanted to examine the relationship of BTM with cortical porosity and risk of non-vertebral fracture. In 211 postmenopausal women aged 54-94 years with non-vertebral fractures and 232 age-matched fracture-free controls from the Tromsø Study, Norway, we quantified femoral neck areal bone mineral density (FN aBMD), femoral subtrochanteric bone architecture, and assessed serum levels of procollagen type I N-terminal propeptide (PINP) and C-terminal cross-linking telopeptide of type I collagen (CTX). Fracture cases exhibited higher PINP and CTX levels, lower FN aBMD, larger total and medullary cross-sectional area (CSA), thinner cortices, and higher cortical porosity of the femoral subtrochanter than controls (p≤0.01). Each SD increment in PINP and CTX was associated with 0.21-0.26 SD lower total volumetric BMD, 0.10-0.14 SD larger total CSA, 0.14-0.18 SD larger medullary CSA, 0.13-0.18 SD thinner cortices, and 0.27-0.33 SD higher porosity of the total cortex, compact cortex, and transitional zone (all p≤0.01). Moreover, each SD of higher PINP and CTX was associated with increased odds for fracture after adjustment for age, height, and weight (ORs 1.49; 95% CI, 1.20-1.85 and OR 1.22; 95% CI, 1.00-1.49, both pfracture after accounting for FN aBMD, cortical porosity or cortical thickness (OR ranging from 1.31 to 1.39, p ranging from 0.005 to 0.028). In summary, increased BTM levels are associated with higher cortical porosity, thinner cortices, larger bone size and higher odds for fracture. We infer that this is produced by increased periosteal apposition, intracortical and endocortical remodeling; and that these changes in bone architecture are predisposing to fracture.

  12. Response of cortical bone to antiresorptive treatment

    DEFF Research Database (Denmark)

    Hyldstrup, Lars; Jørgensen, J T; Sørensen, T K;

    2001-01-01

    A total of 113 postmenopausal women (69 controls, 33 using hormone replacement therapy (HRT), and 11 using bisphosphonate) were evaluated twice over 2 years with a new noninvasive, radiogrammetry-based technique called digital X-ray radiogrammetry (DXR) and conventional bone densitometry of the s...... treatment regimens used in the prevention of osteoporosis....

  13. Is the Alzheimer's disease cortical thickness signature a biological marker for memory?

    Science.gov (United States)

    Busovaca, Edgar; Zimmerman, Molly E; Meier, Irene B; Griffith, Erica Y; Grieve, Stuart M; Korgaonkar, Mayuresh S; Williams, Leanne M; Brickman, Adam M

    2016-06-01

    Recent work suggests that analysis of the cortical thickness in key brain regions can be used to identify individuals at greatest risk for development of Alzheimer's disease (AD). It is unclear to what extent this "signature" is a biological marker of normal memory function - the primary cognitive domain affected by AD. We examined the relationship between the AD signature biomarker and memory functioning in a group of neurologically healthy young and older adults. Cortical thickness measurements and neuropsychological evaluations were obtained in 110 adults (age range 21-78, mean = 46) drawn from the Brain Resource International Database. The cohort was divided into young adult (n = 64, age 21-50) and older adult (n = 46, age 51-78) groups. Cortical thickness analysis was performed with FreeSurfer, and the average cortical thickness extracted from the eight regions that comprise the AD signature. Mean AD-signature cortical thickness was positively associated with performance on the delayed free recall trial of a list learning task and this relationship did not differ between younger and older adults. Mean AD-signature cortical thickness was not associated with performance on a test of psychomotor speed, as a control task, in either group. The results suggest that the AD signature cortical thickness is a marker for memory functioning across the adult lifespan.

  14. Genetic associations between intelligence and cortical thickness emerge at the start of puberty.

    Science.gov (United States)

    Brouwer, Rachel M; van Soelen, Inge L C; Swagerman, Suzanne C; Schnack, Hugo G; Ehli, Erik A; Kahn, René S; Hulshoff Pol, Hilleke E; Boomsma, Dorret I

    2014-08-01

    Cognitive abilities are related to (changes in) brain structure during adolescence and adulthood. Previous studies suggest that associations between cortical thickness and intelligence may be different at different ages. As both intelligence and cortical thickness are heritable traits, the question arises whether the association between cortical thickness development and intelligence is due to genes influencing both traits. We study this association in a longitudinal sample of young twins. Intelligence was assessed by standard IQ tests at age 9 in 224 twins, 190 of whom also underwent structural magnetic resonance imaging (MRI). Three years later at age 12, 177/125 twins returned for a follow-up measurement of intelligence/MRI scanning, respectively. We investigated whether cortical thickness was associated with intelligence and if so, whether this association was driven by genes. At age 9, there were no associations between cortical thickness and intelligence. At age 12, a negative relationship emerged. This association was mainly driven by verbal intelligence, and manifested itself most prominently in the left hemisphere. Cortical thickness and intelligence were explained by the same genes. As a post hoc analysis, we tested whether a specific allele (rs6265; Val66Met in the BDNF gene) contributed to this association. Met carriers showed lower intelligence and a thicker cortex, but only the association between the BDNF genotype and cortical thickness in the left superior parietal gyrus reached significance. In conclusion, it seems that brain areas contributing to (verbal) intellectual performance are specializing under the influence of genes around the onset of puberty.

  15. The Relation of Focal Lesions to Cortical Thickness in Pediatric Traumatic Brain Injury.

    Science.gov (United States)

    Bigler, Erin D; Zielinski, Brandon A; Goodrich-Hunsaker, Naomi; Black, Garrett M; Huff, B S Trevor; Christiansen, Zachary; Wood, Dawn-Marie; Abildskov, Tracy J; Dennis, Maureen; Taylor, H Gerry; Rubin, Kenneth; Vannatta, Kathryn; Gerhardt, Cynthia A; Stancin, Terry; Yeates, Keith Owen

    2016-10-01

    In a sample of children with traumatic brain injury, this magnetic resonance imaging (MRI)-based investigation examined whether presence of a focal lesion uniquely influenced cortical thickness in any brain region. Specifically, the study explored the relation of cortical thickness to injury severity as measured by Glasgow Coma Scale score and length of stay, along with presence of encephalomalacia, focal white matter lesions or presence of hemosiderin deposition as a marker of shear injury. For comparison, a group of children without head injury but with orthopedic injury of similar age and sex were also examined. Both traumatic brain injury and orthopedic injury children had normally reduced cortical thickness with age, assumed to reflect neuronal pruning. However, the reductions observed within the traumatic brain injury sample were similar to those in the orthopedic injury group, suggesting that in this sample traumatic brain injury, per se, did not uniquely alter cortical thickness in any brain region at the group level. Injury severity in terms of Glasgow Coma Scale or longer length of stay was associated with greater reductions in frontal and occipitoparietal cortical thickness. However, presence of focal lesions were not related to unique changes in cortical thickness despite having a prominent distribution of lesions within frontotemporal regions among children with traumatic brain injury. Because focal lesions were highly heterogeneous, their association with cortical thickness and development appeared to be idiosyncratic, and not associated with group level effects.

  16. Automated classification of mandibular cortical bone on dental panoramic radiographs for early detection of osteoporosis

    Science.gov (United States)

    Horiba, Kazuki; Muramatsu, Chisako; Hayashi, Tatsuro; Fukui, Tatsumasa; Hara, Takeshi; Katsumata, Akitoshi; Fujita, Hiroshi

    2015-03-01

    Findings on dental panoramic radiographs (DPRs) have shown that mandibular cortical index (MCI) based on the morphology of mandibular inferior cortex was significantly correlated with osteoporosis. MCI on DPRs can be categorized into one of three groups and has the high potential for identifying patients with osteoporosis. However, most DPRs are used only for diagnosing dental conditions by dentists in their routine clinical work. Moreover, MCI is not generally quantified but assessed subjectively. In this study, we investigated a computer-aided diagnosis (CAD) system that automatically classifies mandibular cortical bone for detection of osteoporotic patients at early stage. First, an inferior border of mandibular bone was detected by use of an active contour method. Second, regions of interest including the cortical bone are extracted and analyzed for its thickness and roughness. Finally, support vector machine (SVM) differentiate cases into three MCI categories by features including the thickness and roughness. Ninety eight DPRs were used to evaluate our proposed scheme. The number of cases classified to Class I, II, and III by a dental radiologist are 56, 25 and 17 cases, respectively. Experimental result based on the leave-one-out cross-validation evaluation showed that the sensitivities for the classes I, II, and III were 94.6%, 57.7% and 94.1%, respectively. Distribution of the groups in the feature space indicates a possibility of MCI quantification by the proposed method. Therefore, our scheme has a potential in identifying osteoporotic patients at an early stage.

  17. Effects of Loading Duration and Short Rest Insertion on Cancellous and Cortical Bone Adaptation in the Mouse Tibia.

    Science.gov (United States)

    Yang, Haisheng; Embry, Rachel E; Main, Russell P

    2017-01-01

    The skeleton's osteogenic response to mechanical loading can be affected by loading duration and rest insertion during a series of loading events. Prior animal loading studies have shown that the cortical bone response saturates quickly and short rest insertions between load cycles can enhance cortical bone formation. However, it remains unknown how loading duration and short rest insertion affect load-induced osteogenesis in the mouse tibial compressive loading model, and particularly in cancellous bone. To address this issue, we applied cyclic loading (-9 N peak load; 4 Hz) to the tibiae of three groups of 16 week-old female C57BL/6 mice for two weeks, with a different number of continuous load cycles applied daily to each group (36, 216 and 1200). A fourth group was loaded under 216 daily load cycles with a 10 s rest insertion after every fourth cycle. We found that as few as 36 load cycles per day were able to induce osteogenic responses in both cancellous and cortical bone. Furthermore, while cortical bone area and thickness continued to increase through 1200 cycles, the incremental increase in the osteogenic response decreased as load number increased, indicating a reduced benefit of the increasing number of load cycles. In the proximal metaphyseal cancellous bone, trabecular thickness increased with load up to 216 cycles. We also found that insertion of a 10 s rest between load cycles did not improve the osteogenic response of the cortical or cancellous tissues compared to continuous loading in this model given the age and sex of the mice and the loading parameters used here. These results suggest that relatively few load cycles (e.g. 36) are sufficient to induce osteogenic responses in both cortical and cancellous bone in the mouse tibial loading model. Mechanistic studies using the mouse tibial loading model to examine bone formation and skeletal mechanobiology could be accomplished with relatively few load cycles.

  18. Evaluation of trabecular bone patterns on dental radiographic images: influence of cortical bone

    Science.gov (United States)

    Amouriq, Yves; Evenou, Pierre; Arlicot, Aurore; Normand, Nicolas; Layrolle, Pierre; Weiss, Pierre; Guédon, Jean-Pierre

    2010-03-01

    For some authors trabecular bone is highly visible in intraoral radiographs. For other authors, the observed intrabony trabecular pattern is a representation of only the endosteal surface of cortical bone, not of intermedullary striae. The purpose of this preliminary study was to investigate the true anatomical structures that are visible in routine dental radiographs and classically denoted trabecular bone. This is a major point for bone texture analysis on radiographs. Computed radiography (CR) images of dog mandible section in molar region were compared with simulations calculated from high-resolution micro-CT volumes. Calculated simulations were obtained using the Mojette Transform. By digitally editing the CT volume, the simulations were separated into trabecular and cortical components into a region of interest. Different images were compared and correlated, some bone micro-architecture parameters calculated. A high correlation was found between computed radiographs and calculated simulations from micro-CT. The Mojette transform was successful to obtain high quality images. Cortical bone did not contribute to change in a major way simulated images. These first results imply that intrabony trabecular pattern observed on radiographs can not only be a representation of the cortical bone endosteal surface and that trabecular bone is highly visible in intraoral radiographs.

  19. Analyzing the anisotropic Hooke's law for children's cortical bone.

    Science.gov (United States)

    Lefèvre, Emmanuelle; Lasaygues, Philippe; Baron, Cécile; Payan, Cédric; Launay, Franck; Follet, Hélène; Pithioux, Martine

    2015-09-01

    Child cortical bone tissue is rarely studied because of the difficulty of obtaining samples. Yet the preparation and ultrasonic characterization of the small samples available, while challenging, is one of the most promising ways of obtaining information on the mechanical behavior of non-pathological children׳s bone. We investigated children׳s cortical bone obtained from chirurgical waste. 22 fibula or femur samples from 21 children (1-18 years old, mean age: 9.7±5.8 years old) were compared to 16 fibula samples from 16 elderly patients (50-95 years old, mean age: 76.2±13.5 years old). Stiffness coefficients were evaluated via an ultrasonic method and anisotropy ratios were calculated as the ratio of C33/C11, C33/C22 and C11/C22. Stiffness coefficients were highly correlated with age in children (R>0.56, p0.5), nor between C44 and C55 (p>0.5). We observe a transverse isotropy with C33>C22=C11>C44C55>C66. For both groups, we found no correlation between age and anisotropy ratios. This study offers the first complete analysis of stiffness coefficients in the three orthogonal bone axes in children, giving some indication of how bone anisotropy is related to age. Future perspectives include studying the effect of the structure and composition of bone on its mechanical behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Quantification of alterations in cortical bone geometry using Site Specificity Software in mouse models of aging and the responses to ovariectomy and altered loading

    Directory of Open Access Journals (Sweden)

    Gabriel L Galea

    2015-04-01

    Full Text Available Investigations into the effect of (remodelling stimuli on cortical bone in rodents normally rely on analysis of changes in bone mass and architecture at a narrow cross-sectional site. However, it is well established that the effects of axial loading produce site-specific changes throughout bones’ structure. Non-mechanical influences (e.g. hormones can be additional to or oppose locally-controlled adaptive responses and may have more generalized effects. Tools currently available to study site-specific cortical bone adaptation are limited. Here we applied novel Site-Specificity software to measure bone mass and architecture at each 1% site along the length of the mouse tibia from standard micro-computed tomography (μCT images. Resulting measures are directly comparable to those obtained through μCT analysis (R2 > 0.96. Site-Specificity Analysis was used to compare a number of parameters in tibiae from young adult (19-week-old versus aged (19-month-old mice; ovariectomized and entire mice; limbs subjected to short periods of axial loading or disuse induced by sciatic neurectomy. Age was associated with uniformly reduced cortical thickness and site-specific decreases in cortical area most apparent in the proximal tibia. Mechanical loading site-specifically increased cortical area and thickness in the proximal tibia. Disuse uniformly decreased cortical thickness and decreased cortical area in the proximal tibia. Ovariectomy uniformly reduced cortical area without altering cortical thickness. Differences in polar moment of inertia between experimental groups were only observed in the proximal tibia. Ageing and ovariectomy also altered eccentricity in the distal tibia. In summary, Site-Specificity Analysis provides a valuable tool for measuring changes in cortical bone mass and architecture along the entire length of a bone. Changes in the (remodelling response determined at a single site may not reflect the response at different locations within

  1. Chronic Hyperglycemia Modulates Rat Osteoporotic Cortical Bone Microarchitecture into Less Fragile Structures

    Directory of Open Access Journals (Sweden)

    Cristina de Mello-Sampayo

    2017-01-01

    Full Text Available There is controversy concerning the diabetes impact on bone quality, notorious in type 2 diabetic postmenopausal women. One pointed cause might be uncontrolled glycemia. In this study, the effect of chronic hyperglycemia in bone turnover, morphology, and biomechanics was evaluated in female Wistar rats in the presence/absence of estrogens (ovariectomy. Animals (n=28 were divided into sham, ovariectomized (OVX, hyperglycemic (streptozotocin 40 mg/kg, single-dose i.p.-STZ, and hyperglycemic-ovariectomized (STZ + OVX animals. Blood biomarkers were estimated 60 days postovariectomy. Body weight, vertebral microarchitecture (L4-histomorphometry, femur biomechanical properties (bending tests, tibia ultrastructure (scanning electron microscopy, and femur and urinary calcium (atomic absorption were also evaluated. The increased PINP/CTX ratio of hyperglycemic animals and the similar ratio between STZ + OVX and healthy animals contrasting with the lower ratio of OVX (in line with its histomorphometric data suggest a tendency for improved bone formation in hyperglycemic-ovariectomized animals. The increased tibia medullar canal, which contrasts with the unaffected cortical thickness of both hyperglycemic groups while that of OVX decreased, was associated to the increased stiffness and strength of STZ + OVX bones compared to those of OVX, in line with the observed ultrastructure. Concluding, chronic hyperglycemia in ovariectomized female rats causes bone morphological changes that translate positively in the ultrastructure and mechanical properties of cortical bones.

  2. Comparative study between cortical bone graft versus bone dust for reconstruction of cranial burr holes.

    Science.gov (United States)

    Worm, Paulo V; Ferreira, Nelson P; Faria, Mario B; Ferreira, Marcelo P; Kraemer, Jorge L; Collares, Marcus V M

    2010-12-22

    As a consequence of the progressive evolution of neurosurgical techniques, there has been increasing concern with the esthetic aspects of burr holes. Therefore, the objective of this study was to compare the use of cortical bone graft and bone dust for correcting cranial deformities caused by neurosurgical trephines. Twenty-three patients were enrolled for cranial burr hole reconstruction with a 1-year follow-up. A total of 108 burr holes were treated; 36 burr holes were reconstructed with autogenous cortical bone discs (33.3%), and the remaining 72 with autogenous wet bone powder (66.6%). A trephine was specifically designed to produce this coin-shaped bone plug of 14 mm in diameter, which fit perfectly over the burr holes. The reconstructions were studied 12 months after the surgical procedure, using three-dimensional quantitative computed tomography. Additionally, general and plastic surgeons blinded for the study evaluated the cosmetic results of those areas, attributing scores from 0 to 10. The mean bone densities were 987.95 ± 186.83 Hounsfield units (HU) for bone fragment and 473.55 ± 220.34 HU for bone dust (P holes because of their lower degree of bone resorption and, consequently, better cosmetic results. The lack of donor site morbidity associated with procedural low cost qualifies the cortical autograft as the first choice for correcting cranial defects created by neurosurgical trephines.

  3. Relationships among Cortical Thickness, Reading Skill, and Print Exposure in Adults

    Science.gov (United States)

    Goldman, Jason G.; Manis, Frank R.

    2013-01-01

    This study investigated relationships among cortical thickness in the left-hemisphere reading network, and reading skill and experience in adult nonimpaired readers. Given the relationship between print exposure and reading, it is possible that print exposure is related to cortical structure. The pattern of correlations indicated that individuals…

  4. Temporal lobe cortical thickness correlations differentiate the migraine brain from the healthy brain.

    Directory of Open Access Journals (Sweden)

    Todd J Schwedt

    Full Text Available Interregional cortical thickness correlations reflect underlying brain structural connectivity and functional connectivity. A few prior studies have shown that migraine is associated with atypical cortical brain structure and atypical functional connectivity amongst cortical regions that participate in sensory processing. However, the specific brain regions that most accurately differentiate the migraine brain from the healthy brain have yet to be determined. The aim of this study was to identify the brain regions that comprised interregional cortical thickness correlations that most differed between migraineurs and healthy controls.This was a cross-sectional brain magnetic resonance imaging (MRI investigation of 64 adults with migraine and 39 healthy control subjects recruited from tertiary-care medical centers and their surrounding communities. All subjects underwent structural brain MRI imaging on a 3T scanner. Cortical thickness was determined for 70 brain regions that cover the cerebral cortex and cortical thickness correlations amongst these regions were calculated. Cortical thickness correlations that best differentiated groups of six migraineurs from controls and vice versa were identified.A model containing 15 interregional cortical thickness correlations differentiated groups of migraineurs from healthy controls with high accuracy. The right temporal pole was involved in 13 of the 15 interregional correlations while the right middle temporal cortex was involved in the other two.A model consisting of 15 interregional cortical thickness correlations accurately differentiates the brains of small groups of migraineurs from those of healthy controls. Correlations with the right temporal pole were highly represented in this classifier, suggesting that this region plays an important role in migraine pathophysiology.

  5. Cancellous and cortical bone imaging by reflected tomography.

    Science.gov (United States)

    Lasaygues, P; Lefebvre, J P

    2001-01-01

    This paper deals with the inverse scattering problem observed when ultrasonic waves are used to analyze biological media. The objective is to image cancellous and cortical bone by ultrasonic reflected tomography (URT). Because strong contrast and high absorbance bodies such as bones cannot be imaged at usual ultrasonic high frequencies (> 1 MHz), we adapted for low-frequency URT (Papoulis deconvolution). This resolution enhancement for human porous vertebrae and human and animal femur showed that high-resolution images can be obtained with low-frequency URT.

  6. Associations between cortical thickness and verbal fluency in childhood, adolescence, and young adulthood.

    Science.gov (United States)

    Porter, James N; Collins, Paul F; Muetzel, Ryan L; Lim, Kelvin O; Luciana, Monica

    2011-04-15

    Neuroimaging studies of normative human brain development indicate that the brain matures at differing rates across time and brain regions, with some areas maturing into young adulthood. In particular, changes in cortical thickness may index maturational progressions from an overabundance of neuropil toward efficiently pruned neural networks. Developmental changes in structural MRI measures have rarely been examined in relation to discrete neuropsychological functions. In this study, healthy right-handed adolescents completed MRI scanning and the Controlled Oral Word Association Test (COWAT). Associations of task performance and cortical thickness were assessed with cortical-surface-based analyses. Significant correlations between increasing COWAT performances and decreasing cortical thickness were found in left hemisphere language regions, including perisylvian regions surrounding Wernicke's and Broca's areas. Task performance was also correlated with regions associated with effortful verbal processing, working memory, and performance monitoring. Structure-function associations were not significantly different between older and younger subjects. Decreases in cortical thicknesses in regions that comprise the language network likely reflect maturation toward adult-like cortical organization and processing efficiency. The changes in cortical thicknesses that support verbal fluency are apparent by middle childhood, but with regionally separate developmental trajectories for males and females, consistent with other studies of adolescent development.

  7. Frontotemporal dementia and language networks: cortical thickness reduction is driven by dyslexia susceptibility genes

    Science.gov (United States)

    Paternicó, Donata; Manes, Marta; Premi, Enrico; Cosseddu, Maura; Gazzina, Stefano; Alberici, Antonella; Archetti, Silvana; Bonomi, Elisa; Cotelli, Maria Sofia; Cotelli, Maria; Turla, Marinella; Micheli, Anna; Gasparotti, Roberto; Padovani, Alessandro; Borroni, Barbara

    2016-01-01

    Variations within genes associated with dyslexia result in a language network vulnerability, and in patients with Frontotemporal Dementia (FTD), language disturbances represent a disease core feature. Here we explored whether variations within three related-dyslexia genes, namely KIAA0319, DCDC2, and CNTNAP, might affect cortical thickness measures in FTD patients. 112 FTD patients underwent clinical and neuropsychological examination, genetic analyses and brain Magnetic Resonance Imaging (MRI). KIAA0319 rs17243157 G/A, DCDC2 rs793842 A/G and CNTNAP2 rs17236239 A/G genetic variations were assessed. Cortical thickness was analysed by Freesurfer. Patients carrying KIAA0319 A*(AG or AA) carriers showed greater cortical thickness atrophy in the left fusiform and inferior temporal gyri, compared to KIAA0319 GG (p ≤ 0.001). Patients carrying CNTNAP2 G*(GA or GG) showed reduced cortical thickness in the left insula thenCNTNAP2 AA carriers (p≤0.001). When patients with both at-risk polymorphisms were considered (KIAA0319 A* and CNTNAP2 G*), greater and addictive cortical thickness atrophy of the left insula and the inferior temporal gyrus was demonstrated (p ≤ 0.001). No significant effect of DCDC2 was found. In FTD, variations of KIAA0319 and CNTNAP2 genes were related to cortical thickness abnormalities in those brain areas involved in language abilities. These findings shed light on genetic predisposition in defining phenotypic variability in FTD. PMID:27484312

  8. Automated scheme for measuring mandibular cortical thickness on dental panoramic radiographs for osteoporosis screening

    Science.gov (United States)

    Matsumoto, T.; Hayashi, T.; Hara, T.; Katsumata, A.; Muramatsu, C.; Zhou, X.; Iida, Y.; Matsuoka, M.; Katagi, Ki.; Fujita, H.

    2012-03-01

    Findings of dental panoramic radiographs (DPRs) have shown that the mandibular cortical thickness (MCT) was significantly correlated with osteoporosis. Identifying asymptomatic patients with osteoporosis through dental examinations may bring a supplemental benefit for the patients. However, most of the DPRs are used for only diagnosing dental conditions by dentists in their routine clinical work. The aim of this study was to develop a computeraided diagnosis scheme that automatically measures MCT to assist dentists in screening osteoporosis. First, the inferior border of mandibular bone was detected by use of an active contour method. Second, the locations of mental foramina were estimated on the basis of the inferior border of mandibular bone. Finally, MCT was measured on the basis of the grayscale profile analysis. One hundred DPRs were used to evaluate our proposed scheme. Experimental results showed that the sensitivity and specificity for identifying osteoporotic patients were 92.6 % and 100 %, respectively. We conducted multiclinic trials, in which 223 cases have been obtained and processed in about a month. Our scheme succeeded in detecting all cases of suspected osteoporosis. Therefore, our scheme may have a potential to identify osteoporotic patients at an early stage.

  9. Automatic Detection of Cortical Bones Haversian Osteonal Boundaries

    Directory of Open Access Journals (Sweden)

    Ilige Hage

    2015-10-01

    Full Text Available This work aims to automatically detect cement lines in decalcified cortical bone sections stained with H&E. Employed is a methodology developed previously by the authors and proven to successfully count and disambiguate the micro-architectural features (namely Haversian canals, canaliculi, and osteocyte lacunae present in the secondary osteons/Haversian system (osteon of cortical bone. This methodology combines methods typically considered separately, namely pulse coupled neural networks (PCNN, particle swarm optimization (PSO, and adaptive threshold (AT. In lieu of human bone, slides (at 20× magnification from bovid cortical bone are used in this study as proxy of human bone. Having been characterized, features with same orientation are used to detect the cement line viewed as the next coaxial layer adjacent to the outermost lamella of the osteon. Employed for this purpose are three attributes for each and every micro-sized feature identified in the osteon lamellar system: (1 orientation, (2 size (ellipse perimeter and (3 Euler number (a topological measure. From a training image, automated parameters for the PCNN network are obtained by forming fitness functions extracted from these attributes. It is found that a 3-way combination of these features attributes yields good representations of the overall osteon boundary (cement line. Near-unity values of classical metrics of quality (precision, sensitivity, specificity, accuracy, and dice suggest that the segments obtained automatically by the optimized artificial intelligent methodology are of high fidelity as compared with manual tracing. For bench marking, cement lines segmented by k-means did not fare as well. An analysis based on the modified Hausdorff distance (MHD of the segmented cement lines also testified to the quality of the detected cement lines vis-a-vis the k-means method.

  10. Repair of microdamage in osteonal cortical bone adjacent to bone screw.

    Directory of Open Access Journals (Sweden)

    Lei Wang

    Full Text Available Up to date, little is known about the repair mode of microdamage in osteonal cortical bone resulting from bone screw implantation. In this study, self-tapping titanium cortical bone screws were inserted into the tibial diaphyses of 24 adult male rabbits. The animals were sacrificed at 1 day, 2 weeks, 1 month and 2 months after surgery. Histomorphometric measurement and confocal microscopy were performed on basic fuchsin stained bone sections to examine the morphological characteristics of microdamage, bone resorption activity and spatial relationship between microdamage and bone resorption. Diffuse and linear cracks were coexisted in peri-screw bone. Intracortical bone resorption was significantly increased 2 weeks after screw installation and reach to the maximum at 1 month. There was no significant difference in bone resorption between 1-month and 2-months groups. Microdamage was significantly decreased within 1 month after surgery. Bone resorption was predisposed to occur in the region of <100 µm from the bone-screw interface, where had extensive diffuse damage mixed with linear cracks. Different patterns of resorption cavities appeared in peri-screw bone. These data suggest that 1 the complex microdamage composed of diffuse damage and linear cracks is a strong stimulator for initiating targeted bone remodeling; 2 bone resorption activities taking place on the surfaces of differently oriented Haversian and Volkmann canals work in a team for the repair of extensive microdamage; 3 targeted bone remodeling is a short-term reaction to microdamage and thereby it may not be able to remove all microdamage resulting from bone screw insertion.

  11. Measurement of renal cortical thickness using spiral CT in early diabetic nephropathy

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Bong Sig; Chung, Won Jung; Park, Byeong Ho; Choi, Jong Cheol; Nam, Kyung Jin; Lee, Yung Il; Chung, Duk Hwan [Donga Univ. College of Medicine, Pusan (Korea, Republic of)

    1997-03-01

    To compare the ratio of renal cortical thickness to renal parenchymal thickness in early diabetic nephropathy and in normal control group. We performed spiral CT in 17 patients suffering from diabetic nephropathy without renal failure or renal atrophy. The normal control group consisted of 19 persons who were normal on renal function test and did not show any abnormality of the kidney. Renal cortical and parenchymal thicknesses were measured at renal hilum level perpendicular to the renal surface by electronic caliper on contrast-enhanced transverse scan demonstrating the cortical nephrogram phase. Using student's test, the difference in renal parenchymal and cortical thickness between the two groups was tested for statistical significance. There was no significant difference in renal parenchymal thickness between the two groups (p>0.05);the patient group had a thicker renal cortex than the normal control group however (p<0.05). The ratio of renal cortical thickness to parenchymal thickness in early diabetic nephropathy patients (Rt.:0.041{+-}0.051, Lt.:0.382{+-}0.053) was significantly higher than in the normal control group (Rt.:0.331{+-}0.067, Lt.:0.323{+-}0.064). The kidney of early diabetic nephropathy patients had a thicker renal cortex than normal kidney.

  12. Cortical thickness difference across the central sulcus visualized in the presence of vasogenic edema

    Energy Technology Data Exchange (ETDEWEB)

    Togao, Osamu [Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582 (Japan)], E-mail: togao@dr.hosp.kyushu-u.ac.jp; Yoshiura, Takashi; Mihara, Futoshi; Noguchi, Tomoyuki; Hiwatashi, Akio; Yamashita, Koji; Yoshitake, Tadamasa; Honda, Hiroshi [Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582 (Japan)

    2008-05-15

    Purpose: To confirm the cortical thickness difference across the central sulcus (CS) visualized in the presence of vasogenic edema on MRI. Materials and methods: T2-weighted images of 70 cerebral hemispheres showing vasogenic edema infiltrating into subcortical white matter around the CS were studied retrospectively. Two neuroradiologists measured the cortical thickness of the anterior and posterior banks of the CS, precentral sulci (PrCS), and postcentral sulci (PoCS). Additionally, we compared the cortical thickness of the anterior and posterior banks of each sulcus visually using a grading scale. Results: On T2-weighted images, the cerebral cortex was highlighted by a high signal-intensity vasogenic edema in the adjacent white matter, and its thickness was readily measurable. The unique cortical thickness difference between the anterior and posterior banks of the CS were confirmed with measurements of 2.67 and 1.48 mm (p < 0.0001). The cortical measurements across other cerebral sulci were 2.04 and 1.95 mm (NS) for the PrCS, and 1.67 and 1.77 mm (NS) for the PoCS. The cortical thickness ratios were 1.86 for the CS, 1.05 for the PrCS, and 0.96 for the PoCS. On visual evaluation, the anterior bank of the CS was thicker than the posterior bank in 93% (65/70). For the PrCS and PoCS, the thickness of the anterior and posterior banks appeared to be equal in over 70% of the patients. Conclusion: A prominent cortical thickness difference across the CS in the presence of vasogenic edema was confirmed. This finding is considered to facilitate the identification of the CS in patients with brain tumors.

  13. Dark-field transmission electron microscopy of cortical bone reveals details of extrafibrillar crystals.

    Science.gov (United States)

    Schwarcz, Henry P; McNally, Elizabeth A; Botton, Gianluigi A

    2014-12-01

    In a previous study we showed that most of the mineral in bone is present in the form of "mineral structures", 5-6nm-thick, elongated plates which surround and are oriented parallel to collagen fibrils. Using dark-field transmission electron microscopy, we viewed mineral structures in ion-milled sections of cortical human bone cut parallel to the collagen fibrils. Within the mineral structures we observe single crystals of apatite averaging 5.8±2.7nm in width and 28±19nm in length, their long axes oriented parallel to the fibril axis. Some appear to be composite, co-aligned crystals as thin as 2nm. From their similarity to TEM images of crystals liberated from deproteinated bone we infer that we are viewing sections through platy crystals of apatite that are assembled together to form the mineral structures.

  14. Comparison of gray matter volume and thickness for analysis of cortical changes in Alzheimer's disease

    Science.gov (United States)

    Liu, Jiachao; Li, Ziyi; Chen, Kewei; Yao, Li; Wang, Zhiqun; Li, Kunchen; Guo, Xiaojuan

    2011-03-01

    Gray matter volume and cortical thickness are two indices of concern in brain structure magnetic resonance imaging research. Gray matter volume reflects mixed-measurement information of cerebral cortex, while cortical thickness reflects only the information of distance between inner surface and outer surface of cerebral cortex. Using Scaled Subprofile Modeling based on Principal Component Analysis (SSM_PCA) and Pearson's Correlation Analysis, this study further provided quantitative comparisons and depicted both global relevance and local relevance to comprehensively investigate morphometrical abnormalities in cerebral cortex in Alzheimer's disease (AD). Thirteen patients with AD and thirteen age- and gender-matched healthy controls were included in this study. Results showed that factor scores from the first 8 principal components accounted for ~53.38% of the total variance for gray matter volume, and ~50.18% for cortical thickness. Factor scores from the fifth principal component showed significant correlation. In addition, gray matter voxel-based volume was closely related to cortical thickness alterations in most cortical cortex, especially, in some typical abnormal brain regions such as insula and the parahippocampal gyrus in AD. These findings suggest that these two measurements are effective indices for understanding the neuropathology in AD. Studies using both gray matter volume and cortical thickness can separate the causes of the discrepancy, provide complementary information and carry out a comprehensive description of the morphological changes of brain structure.

  15. Altered brain structural networks in attention deficit/hyperactivity disorder children revealed by cortical thickness.

    Science.gov (United States)

    Liu, Tian; Chen, Yanni; Li, Chenxi; Li, Youjun; Wang, Jue

    2017-01-18

    This study investigated the cortical thickness and topological features of human brain anatomical networks related to attention deficit/hyperactivity disorder. Data were collected from 40 attention deficit/hyperactivity disorder children and 40 normal control children. Interregional correlation matrices were established by calculating the correlations of cortical thickness between all pairs of cortical regions (68 regions) of the whole brain. Further thresholds were applied to create binary matrices to construct a series of undirected and unweighted graphs, and global, local, and nodal efficiencies were computed as a function of the network cost. These experimental results revealed abnormal cortical thickness and correlations in attention deficit/hyperactivity disorder, and showed that the brain structural networks of attention deficit/hyperactivity disorder subjects had inefficient small-world topological features. Furthermore, their topological properties were altered abnormally. In particular, decreased global efficiency combined with increased local efficiency in attention deficit/hyperactivity disorder children led to a disorder-related shift of the network topological structure toward regular networks. In addition, nodal efficiency, cortical thickness, and correlation analyses revealed that several brain regions were altered in attention deficit/hyperactivity disorder patients. These findings are in accordance with a hypothesis of dysfunctional integration and segregation of the brain in patients with attention deficit/hyperactivity disorder and provide further evidence of brain dysfunction in attention deficit/hyperactivity disorder patients by observing cortical thickness on magnetic resonance imaging.

  16. Propagation of ultrasonic guided waves in an acrylic plate as a cortical-bone-mimicking phantom

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Il [Kangwon National University, Chuncheon (Korea, Republic of); Choi, Bok Kyoung [Maritime Security Research Center, KIOST, Ansan (Korea, Republic of)

    2014-12-15

    The present study aims to investigate the propagation of ultrasonic guided waves in an acrylic plate as a cortical-bone-mimicking phantom. The velocities of the guided waves in a 5-mm-thick acrylic plate were measured by using the axial transmission technique. A pure A0 Lamb mode could be successfully launched in the 5-mm-thick acrylic plate through a time reversal process of Lamb waves, consistent with the fact that the time reversal process can automatically compensate for the dispersive nature of Lamb waves. The experimental velocities of the slow guided wave (SGW) and the time-reversed Lamb wave were found to be in reasonable agreement with the theoretical group velocity of the A0 Lamb mode, suggesting that both the SGW and the time-reversed Lamb wave excited in the 5-mm-thick acrylic plate correspond to the A0 Lamb mode. These results suggest that the time reversal process of Lamb waves can be usefully applied to noninvasive characterization of long cortical bones.

  17. Influence of estrogen deficiency and tibolone therapy on trabecular and cortical bone evaluated by computed radiography system in rats

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Ana Carolina Bergmann de; Henriques, Helene Nara [Postgraduate Program in Pathology, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Fernandes, Gustavo Vieira Oliveira [Postgraduate Program in Medical Sciences, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Lima, Inaya; Oliveira, Davi Ferreira de; Lopes, Ricardo Tadeu [Nuclear Engineering Program, Federal University of Rio de Janeiro (UFRJ), RJ (Brazil); Pantaleao, Jose Augusto Soares [Maternal and Child Department, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Granjeiro, Jose Mauro [Department of Cellular and Molecular Biology, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Silva, Maria Angelica Guzman [Department of Pathology, Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil)

    2012-03-15

    Purpose: To verify the effects of tibolone administration on trabecular and cortical bone of ovariectomized female rats by computed radiography system (CRS). Methods: The experiment was performed on two groups of rats previously ovariectomized, one received tibolone (OVX+T) while the other did not (OVX), those groups were compared to a control group (C) not ovariectomized. Tibolone administration (1 mg/day) began thirty days after the ovariectomy and the treatment remained for five months. At last, the animals were euthanized and femurs and tibias collected. Computed radiographs of the bones were obtained and the digital images were used to determine the bone optical density and cortical thickness on every group. All results were statistically evaluated with significance set at P<0.05%. Results: Tibolone administration was shown to be beneficial only in the densitometric analysis of the femoral head, performing higher optical density compared to OVX. No difference was found in cortical bone thickness. Conclusion: Ovariectomy caused bone loss in the analyzed regions and tibolone administered in high doses over a long period showed not to be fully beneficial, but preserved bone mass in the femoral head. (author)

  18. Comparative study between cortical bone graft versus bone dust for reconstruction of cranial burr holes

    OpenAIRE

    Worm, Paulo Valdeci; Ferreira,Nelson Pires; Faria, Mário de Barros; Ferreira, Marcelo Paglioli; Kraemer,Jorge Luiz; Collares, Marcus Vinicius Martins

    2010-01-01

    Background: As a consequence of the progressive evolution of neurosurgical techniques, there has been increasing concern with the esthetic aspects of burr holes. Therefore, the objective of this study was to compare the use of cortical bone graft and bone dust for correcting cranial deformities caused by neurosurgical trephines. Methods: Twenty-three patients were enrolled for cranial burr hole reconstruction with a 1-year follow-up. A total of 108 burr holes were treated; 36 burr holes were ...

  19. Correlations between brain cortical thickness and cutaneous pain thresholds are atypical in adults with migraine.

    Directory of Open Access Journals (Sweden)

    Todd J Schwedt

    Full Text Available BACKGROUND/OBJECTIVE: Migraineurs have atypical pain processing, increased expectations for pain, and hypervigilance for pain. Recent studies identified correlations between brain structure and pain sensation in healthy adults. The objective of this study was to compare cortical thickness-to-pain threshold correlations in migraineurs to healthy controls. We hypothesized that migraineurs would have aberrant relationships between the anatomical neurocorrelates of pain processing and pain thresholds. METHODS: Pain thresholds to cutaneously applied heat were determined for 31 adult migraineurs and 32 healthy controls. Cortical thickness was determined from magnetic resonance imaging T1-weighted sequences. Regional cortical thickness-to-pain threshold correlations were determined for migraineurs and controls separately using a general linear model whole brain vertex-wise analysis. A pain threshold-by-group interaction analysis was then conducted to estimate regions where migraineurs show alterations in the pain threshold-to-cortical thickness correlations relative to healthy controls. RESULTS: Controls had negative correlations (p<0.01 uncorrected between pain thresholds and cortical thickness in left posterior cingulate/precuneus, right superior temporal, right inferior parietal, and left inferior temporal regions, and a negative correlation (p<0.01 Monte Carlo corrected with a left superior temporal/inferior parietal region. Migraineurs had positive correlations (p<0.01 uncorrected between pain thresholds and cortical thickness in left superior temporal/inferior parietal, right precuneus, right superior temporal/inferior parietal, and left inferior parietal regions. Cortical thickness-to-pain threshold correlations differed between migraine and control groups (p<0.01 uncorrected for right superior temporal/inferior parietal, right precentral, left posterior cingulate/precuneus, and right inferior parietal regions and (p<0.01 Monte Carlo corrected

  20. 4D segmentation of brain MR images with constrained cortical thickness variation.

    Directory of Open Access Journals (Sweden)

    Li Wang

    Full Text Available Segmentation of brain MR images plays an important role in longitudinal investigation of developmental, aging, disease progression changes in the cerebral cortex. However, most existing brain segmentation methods consider multiple time-point images individually and thus cannot achieve longitudinal consistency. For example, cortical thickness measured from the segmented image will contain unnecessary temporal variations, which will affect the time related change pattern and eventually reduce the statistical power of analysis. In this paper, we propose a 4D segmentation framework for the adult brain MR images with the constraint of cortical thickness variations. Specifically, we utilize local intensity information to address the intensity inhomogeneity, spatial cortical thickness constraint to maintain the cortical thickness being within a reasonable range, and temporal cortical thickness variation constraint in neighboring time-points to suppress the artificial variations. The proposed method has been tested on BLSA dataset and ADNI dataset with promising results. Both qualitative and quantitative experimental results demonstrate the advantage of the proposed method, in comparison to other state-of-the-art 4D segmentation methods.

  1. Cortical thickness estimation in longitudinal stroke studies: A comparison of 3 measurement methods.

    Science.gov (United States)

    Li, Qi; Pardoe, Heath; Lichter, Renee; Werden, Emilio; Raffelt, Audrey; Cumming, Toby; Brodtmann, Amy

    2015-01-01

    There is considerable controversy about the causes of cognitive decline after stroke, with evidence for both the absence and coexistence of Alzheimer pathology. A reduction in cortical thickness has been shown to be an important biomarker for the progression of many neurodegenerative diseases, including Alzheimer's disease (AD). However, brain volume changes following stroke are not well described. Cortical thickness estimation presents an ideal way to detect regional and global post-stroke brain atrophy. In this study, we imaged a group of patients in the first month after stroke and at 3 months. We compared three methods of estimating cortical thickness on unmasked images: one surface-based (FreeSurfer) and two voxel-based methods (a Laplacian method and a registration method, DiRecT). We used three benchmarks for our analyses: accuracy of segmentation (especially peri-lesional performance), reproducibility, and biological validity. We found important differences between these methods in cortical thickness values and performance in high curvature areas and peri-lesional regions, but similar reproducibility metrics. FreeSurfer had less reliance on manual boundary correction than the other two methods, while reproducibility was highest in the Laplacian method. A discussion of the caveats for each method and recommendations for use in a stroke population is included. We conclude that both surface- and voxel-based methods are valid for estimating cortical thickness in stroke populations.

  2. Cortical thickness and surface area in neonates at high risk for schizophrenia.

    Science.gov (United States)

    Li, Gang; Wang, Li; Shi, Feng; Lyall, Amanda E; Ahn, Mihye; Peng, Ziwen; Zhu, Hongtu; Lin, Weili; Gilmore, John H; Shen, Dinggang

    2016-01-01

    Schizophrenia is a neurodevelopmental disorder associated with subtle abnormal cortical thickness and cortical surface area. However, it is unclear whether these abnormalities exist in neonates associated with genetic risk for schizophrenia. To this end, this preliminary study was conducted to identify possible abnormalities of cortical thickness and surface area in the high-genetic-risk neonates. Structural magnetic resonance images were acquired from offspring of mothers (N = 21) who had schizophrenia (N = 12) or schizoaffective disorder (N = 9), and also matched healthy neonates of mothers who were free of psychiatric illness (N = 26). Neonatal cortical surfaces were reconstructed and parcellated as regions of interest (ROIs), and cortical thickness for each vertex was computed as the shortest distance between the inner and outer surfaces. Comparisons were made for the average cortical thickness and total surface area in each of 68 cortical ROIs. After false discovery rate (FDR) correction, it was found that the female high-genetic-risk neonates had significantly thinner cortical thickness in the right lateral occipital cortex than the female control neonates. Before FDR correction, the high-genetic-risk neonates had significantly thinner cortex in the left transverse temporal gyrus, left banks of superior temporal sulcus, left lingual gyrus, right paracentral cortex, right posterior cingulate cortex, right temporal pole, and right lateral occipital cortex, compared with the control neonates. Before FDR correction, in comparison with control neonates, male high-risk neonates had significantly thicker cortex in the left frontal pole, left cuneus cortex, and left lateral occipital cortex; while female high-risk neonates had significantly thinner cortex in the bilateral paracentral, bilateral lateral occipital, left transverse temporal, left pars opercularis, right cuneus, and right posterior cingulate cortices. The high-risk neonates also had significantly

  3. Bone balance within a cortical BMU: local controls of bone resorption and formation.

    Directory of Open Access Journals (Sweden)

    David W Smith

    Full Text Available Maintaining bone volume during bone turnover by a BMU is known as bone balance. Balance is required to maintain structural integrity of the bone and is often dysregulated in disease. Consequently, understanding how a BMU controls bone balance is of considerable interest. This paper develops a methodology for identifying potential balance controls within a single cortical BMU. The theoretical framework developed offers the possibility of a directed search for biological processes compatible with the constraints of balance control. We first derive general control constraint equations and then introduce constitutive equations to identify potential control processes that link key variables that describe the state of the BMU. The paper describes specific local bone volume balance controls that may be associated with bone resorption and bone formation. Because bone resorption and formation both involve averaging over time, short-term fluctuations in the environment are removed, leaving the control systems to manage deviations in longer-term trends back towards their desired values. The length of time for averaging is much greater for bone formation than for bone resorption, which enables more filtering of variability in the bone formation environment. Remarkably, the duration for averaging of bone formation may also grow to control deviations in long-term trends of bone formation. Providing there is sufficient bone formation capacity by osteoblasts, this leads to an extraordinarily robust control mechanism that is independent of either osteoblast number or the cellular osteoid formation rate. A complex picture begins to emerge for the control of bone volume. Different control relationships may achieve the same objective, and the 'integration of information' occurring within a BMU may be interpreted as different sets of BMU control systems coming to the fore as different information is supplied to the BMU, which in turn leads to different observable

  4. Bone balance within a cortical BMU: local controls of bone resorption and formation.

    Science.gov (United States)

    Smith, David W; Gardiner, Bruce S; Dunstan, Colin

    2012-01-01

    Maintaining bone volume during bone turnover by a BMU is known as bone balance. Balance is required to maintain structural integrity of the bone and is often dysregulated in disease. Consequently, understanding how a BMU controls bone balance is of considerable interest. This paper develops a methodology for identifying potential balance controls within a single cortical BMU. The theoretical framework developed offers the possibility of a directed search for biological processes compatible with the constraints of balance control. We first derive general control constraint equations and then introduce constitutive equations to identify potential control processes that link key variables that describe the state of the BMU. The paper describes specific local bone volume balance controls that may be associated with bone resorption and bone formation. Because bone resorption and formation both involve averaging over time, short-term fluctuations in the environment are removed, leaving the control systems to manage deviations in longer-term trends back towards their desired values. The length of time for averaging is much greater for bone formation than for bone resorption, which enables more filtering of variability in the bone formation environment. Remarkably, the duration for averaging of bone formation may also grow to control deviations in long-term trends of bone formation. Providing there is sufficient bone formation capacity by osteoblasts, this leads to an extraordinarily robust control mechanism that is independent of either osteoblast number or the cellular osteoid formation rate. A complex picture begins to emerge for the control of bone volume. Different control relationships may achieve the same objective, and the 'integration of information' occurring within a BMU may be interpreted as different sets of BMU control systems coming to the fore as different information is supplied to the BMU, which in turn leads to different observable BMU behaviors.

  5. Childhood cognitive ability accounts for associations between cognitive ability and brain cortical thickness in old age.

    Science.gov (United States)

    Karama, S; Bastin, M E; Murray, C; Royle, N A; Penke, L; Muñoz Maniega, S; Gow, A J; Corley, J; Valdés Hernández, M del C; Lewis, J D; Rousseau, M-É; Lepage, C; Fonov, V; Collins, D L; Booth, T; Rioux, P; Sherif, T; Adalat, R; Starr, J M; Evans, A C; Wardlaw, J M; Deary, I J

    2014-05-01

    Associations between brain cortical tissue volume and cognitive function in old age are frequently interpreted as suggesting that preservation of cortical tissue is the foundation of successful cognitive aging. However, this association could also, in part, reflect a lifelong association between cognitive ability and cortical tissue. We analyzed data on 588 subjects from the Lothian Birth Cohort 1936 who had intelligence quotient (IQ) scores from the same cognitive test available at both 11 and 70 years of age as well as high-resolution brain magnetic resonance imaging data obtained at approximately 73 years of age. Cortical thickness was estimated at 81 924 sampling points across the cortex for each subject using an automated pipeline. Multiple regression was used to assess associations between cortical thickness and the IQ measures at 11 and 70 years. Childhood IQ accounted for more than two-third of the association between IQ at 70 years and cortical thickness measured at age 73 years. This warns against ascribing a causal interpretation to the association between cognitive ability and cortical tissue in old age based on assumptions about, and exclusive reference to, the aging process and any associated disease. Without early-life measures of cognitive ability, it would have been tempting to conclude that preservation of cortical thickness in old age is a foundation for successful cognitive aging when, instead, it is a lifelong association. This being said, results should not be construed as meaning that all studies on aging require direct measures of childhood IQ, but as suggesting that proxy measures of prior cognitive function can be useful to take into consideration.

  6. Association between cortical thickness and CSF biomarkers in mild cognitive impairment and Alzheimer’s disease

    DEFF Research Database (Denmark)

    Mohades, Sara; Dubois, Jonathan; Parent, Maxime;

    between cortical thinning, amyloidosis or tau hyperphosphorylation depends on cortical regions and clinical stages of AD. Methods: T1-weighed MRIs and associated CSF markers from individuals with mild cognitive impairment (MCI; 16), Alzheimer Disease (AD; n¼7) and age-matched cognitively normal subjects...... regional cortical thinning (CT) measured by Magnetic Resonance Imaging (MRI) and brain amyloidosis (measured by CSF Ab 1-42 concentrations), or tau hyperphosphorylation (tau 181; p-tau) in Alzheimer’s Disease (AD) and Mild Cognitive Impairment (MCI) patients. We test the hypothesis that the association...... (CN; n¼8) were obtained from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort. Cortical surface reconstruction and group registration were generated using Freesurfer. A general linear model was used to conduct regressions between CSF markers and cortical thickness. Results: Correlation...

  7. Two-wave behavior under various conditions of transition area from cancellous bone to cortical bone.

    Science.gov (United States)

    Nagatani, Yoshiki; Mizuno, Katsunori; Matsukawa, Mami

    2014-07-01

    The two-wave phenomenon, the wave separation of a single ultrasonic pulse in cancellous bone, is expected to be a useful tool for the diagnosis of osteoporosis. However, because actual bone has a complicated structure, precise studies on the effect of transition conditions between cortical and cancellous parts are required. This study investigated how the transition condition influenced the two-wave generation using three-dimensional X-ray CT images of an equine radius and a three-dimensional simulation technique. As a result, any changes in the boundary between cortical part and trabecular part, which gives the actual complex structure of bone, did not eliminate the generation of either the primary wave or the secondary wave at least in the condition of clear trabecular alignment. The results led us to the possibility of using the two-wave phenomenon in a diagnostic system for osteoporosis in cases of a complex boundary.

  8. Longitudinal data on cortical thickness before and after working memory training

    Science.gov (United States)

    Metzler-Baddeley, Claudia; Caeyenberghs, Karen; Foley, Sonya; Jones, Derek K.

    2016-01-01

    The data and supplementary information provided in this article relate to our research article “Task complexity and location specific changes of cortical thickness in executive and salience networks after working memory training” (Metzler-Baddeley et al., 2016) [1]. We provide cortical thickness and subcortical volume data derived from parieto-frontal cortical regions and the basal ganglia with the FreeSurfer longitudinal analyses stream (http://surfer.nmr.mgh.harvard.edu [2]) before and after Cogmed working memory training (Cogmed and Cogmed Working Memory Training, 2012) [3]. This article also provides supplementary information to the research article, i.e., within-group comparisons between baseline and outcome cortical thickness and subcortical volume measures, between-group tests of performance changes in cognitive benchmark tests (www.cambridgebrainsciences.com [4]), correlation analyses between performance changes in benchmark tests and training-related structural changes, correlation analyses between the time spent training and structural changes, a scatterplot of the relationship between cortical thickness measures derived from the occipital lobe as control region and the chronological order of the MRI sessions to assess potential scanner drift effects and a post-hoc vertex-wise whole brain analysis with FreeSurfer Qdec (https://surfer.nmr.mgh.harvard.edu/fswiki/Qdec [5]). PMID:27115029

  9. Investigating relationships between cortical thickness and cognitive performance in patients with schizophrenia and healthy adults.

    Science.gov (United States)

    Hartberg, Cecilie Bhandari; Lawyer, Glenn; Nyman, Håkan; Jönsson, Erik G; Haukvik, Unn K; Saetre, Peter; Bjerkan, Petr S; Andreassen, Ole A; Hall, Håkan; Agartz, Ingrid

    2010-05-30

    Relationships between prefrontal and temporal lobe grey matter volumes as assessed by magnetic resonance imaging and neurocognitive test results have been reported in schizophrenia. This investigation aimed to localize brain regions where cortical thickness and neurocognitive performance were related, and investigate if such relationships might differ in schizophrenia patients and healthy controls. Sixty-seven patients with schizophrenia and 69 healthy controls were characterized by neurocognitive testing and by brain cortical thickness maps. Putative cortical thickness/cognitive score relationships were investigated with contrast analyses of general linear models for the combined sample. Regions in which relationships were present were further investigated for diagnostic interaction. In the combined sample, significant positive relationships were found between frontal, temporal and occipital regions and tests for verbal IQ, verbal learning and executive functions. Diagnostic interaction was found for the relationships between verbal IQ and the right temporo-occipital junction and the left middle occipital gyrus. In conclusion, the significant relationships between cortical thickness and neurocognitive performances were localized in brain areas known to be involved in cognition. The relationships were similar in patients and controls, except for the right temporo-occipital and left occipital cortical areas, indicating a disrupted structure-function relationship in patients with schizophrenia compared to healthy control subjects.

  10. Effect of specimen geometry on tensile strength of cortical bone.

    Science.gov (United States)

    Feng, Liang; Jasiuk, Iwona

    2010-11-01

    We investigate the effect of specimen geometry on the ultimate tensile strength of cortical bone measured by a tensile test. This article is motivated by the fact that there is no clear consensus in the literature on a suitable specimen shape for cortical bone testing. We consider three commonly used tensile test specimen shapes: strip, dumbbell with sharp junctions, and dumbbell with rounded junctions. We conduct this study computationally, using a finite element method, and experimentally by testing porcine femurs. Our results show that local stress concentration factors in the specimen lead to reduced values in the measured tensile strength. The higher the stress concentrations are, the lower is the measured strength. We find that the strip specimens are not a good choice due to high stress concentrations. For the same reason, dumbbell specimens with sharp junctions between the grip and gage sections should also be avoided. The dumbbell shaped tensile test specimens with an arc transition and a maximized radius of fillet are a better choice because such geometry lowers stress concentrations.

  11. Cortical thickness maturation and duration of music training: health-promoting activities shape brain development.

    Science.gov (United States)

    Hudziak, James J; Albaugh, Matthew D; Ducharme, Simon; Karama, Sherif; Spottswood, Margaret; Crehan, Eileen; Evans, Alan C; Botteron, Kelly N

    2014-11-01

    To assess the extent to which playing a musical instrument is associated with cortical thickness development among healthy youths. Participants were part of the National Institutes of Health (NIH) Magnetic Resonance Imaging (MRI) Study of Normal Brain Development. This study followed a longitudinal design such that participants underwent MRI scanning and behavioral testing on up to 3 separate visits, occurring at 2-year intervals. MRI, IQ, and music training data were available for 232 youths (334 scans), ranging from 6 to 18 years of age. Cortical thickness was regressed against the number of years that each youth had played a musical instrument. Next, thickness was regressed against an "Age × Years of Playing" interaction term. Age, gender, total brain volume, and scanner were controlled for in analyses. Participant ID was entered as a random effect to account for within-person dependence. False discovery rate correction was applied (p ≤ .05). There was no association between thickness and years playing a musical instrument. The "Age × Years of Playing" interaction was associated with thickness in motor, premotor, and supplementary motor cortices, as well as prefrontal and parietal cortices. Follow-up analysis revealed that music training was associated with an increased rate of thickness maturation. Results were largely unchanged when IQ and handedness were included as covariates. Playing a musical instrument was associated with more rapid cortical thickness maturation within areas implicated in motor planning and coordination, visuospatial ability, and emotion and impulse regulation. However, given the quasi-experimental nature of this study, we cannot rule out the influence of confounding variables. Copyright © 2014 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

  12. Regional brain differences in cortical thickness, surface area and subcortical volume in individuals with Williams syndrome.

    Science.gov (United States)

    Meda, Shashwath A; Pryweller, Jennifer R; Thornton-Wells, Tricia A

    2012-01-01

    Williams syndrome (WS) is a rare genetic neurodevelopmental disorder characterized by increased non-social anxiety, sensitivity to sounds and hypersociability. Previous studies have reported contradictory findings with regard to regional brain variation in WS, relying on only one type of morphological measure (usually volume) in each study. The present study aims to contribute to this body of literature and perhaps elucidate some of these discrepancies by examining concurrent measures of cortical thickness, surface area and subcortical volume between WS subjects and typically-developing (TD) controls. High resolution MRI scans were obtained on 31 WS subjects and 50 typically developing control subjects. We derived quantitative regional estimates of cortical thickness, cortical surface area, and subcortical volume using FreeSurfer software. We evaluated between-group ROI differences while controlling for total intracranial volume. In post-hoc exploratory analyses within the WS group, we tested for correlations between regional brain variation and Beck Anxiety Inventory scores. Consistent with our hypothesis, we detected complex patterns of between-group cortical variation, which included lower surface area in combination with greater thickness in the following cortical regions: post central gyrus, cuneus, lateral orbitofrontal cortex and lingual gyrus. Additional cortical regions showed between-group differences in one (but not both) morphological measures. Subcortical volume was lower in the basal ganglia and the hippocampus in WS versus TD controls. Exploratory correlations revealed that anxiety scores were negatively correlated with gray matter surface area in insula, OFC, rostral middle frontal, superior temporal and lingual gyrus. Our results were consistent with previous reports showing structural alterations in regions supporting the socio-affective and visuospatial impairments in WS. However, we also were able to effectively capture novel and complex

  13. Cortical thickness changes correlate with cognition changes after cognitive training: Evidence from a Chinese community study

    Directory of Open Access Journals (Sweden)

    Lijuan eJiang

    2016-05-01

    Full Text Available The aim of this study was to investigate whether changes in cortical thickness correlated with cognitive function changes in healthy older adults after receiving cognitive training interventions. Moreover, it also aimed to examine the differential impacts of a multi-domain and a single-domain cognitive training interventions. Longitudinal magnetic resonance imaging (MRI scanning was performed on participants 65 to 75 years of age using the Siemens 3.0 T Trio Tim with the MPRAGE sequence. The cortical thickness was determined using FreeSurfer software. Cognitive functioning was evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS. There were significant group × time interaction effects on the left supramarginal, the left frontal pole cortical regions; and a marginal significant group × time interaction effects on visuospatial/constructional and delayed memory scores. In a multi-domain cognitive training group, a number of cortical region changes were significantly positively correlated with changes in attention, delayed memory, and the total score, but significantly negatively correlated with changes in immediate memory and language scores. In the single-domain cognitive training group, some cortical region changes were significantly positively associated with changes in immediate memory, delayed memory, and the total score, while they were significantly negatively associated with changes in visuospatial/constructional, language, and attention scores. Overall, multi-domain cognitive training offered more advantages in visuospatial/constructional, attention, and delayed memory abilities, while single-domain cognitive training benefited immediate memory ability more effectively. These findings suggest that healthy older adults benefit more from the multi-domain cognitive training than single-domain cognitive training. Cognitive training has impacted on cortical thickness changes in healthy elderly

  14. Regional brain differences in cortical thickness, surface area and subcortical volume in individuals with Williams syndrome.

    Directory of Open Access Journals (Sweden)

    Shashwath A Meda

    Full Text Available Williams syndrome (WS is a rare genetic neurodevelopmental disorder characterized by increased non-social anxiety, sensitivity to sounds and hypersociability. Previous studies have reported contradictory findings with regard to regional brain variation in WS, relying on only one type of morphological measure (usually volume in each study. The present study aims to contribute to this body of literature and perhaps elucidate some of these discrepancies by examining concurrent measures of cortical thickness, surface area and subcortical volume between WS subjects and typically-developing (TD controls. High resolution MRI scans were obtained on 31 WS subjects and 50 typically developing control subjects. We derived quantitative regional estimates of cortical thickness, cortical surface area, and subcortical volume using FreeSurfer software. We evaluated between-group ROI differences while controlling for total intracranial volume. In post-hoc exploratory analyses within the WS group, we tested for correlations between regional brain variation and Beck Anxiety Inventory scores. Consistent with our hypothesis, we detected complex patterns of between-group cortical variation, which included lower surface area in combination with greater thickness in the following cortical regions: post central gyrus, cuneus, lateral orbitofrontal cortex and lingual gyrus. Additional cortical regions showed between-group differences in one (but not both morphological measures. Subcortical volume was lower in the basal ganglia and the hippocampus in WS versus TD controls. Exploratory correlations revealed that anxiety scores were negatively correlated with gray matter surface area in insula, OFC, rostral middle frontal, superior temporal and lingual gyrus. Our results were consistent with previous reports showing structural alterations in regions supporting the socio-affective and visuospatial impairments in WS. However, we also were able to effectively capture novel and

  15. Cortical thickness development of human primary visual cortex related to the age of blindness onset.

    Science.gov (United States)

    Li, Qiaojun; Song, Ming; Xu, Jiayuan; Qin, Wen; Yu, Chunshui; Jiang, Tianzi

    2016-07-28

    Blindness primarily induces structural alteration in the primary visual cortex (V1). Some studies have found that the early blind subjects had a thicker V1 compared to sighted controls, whereas late blind subjects showed no significant differences in the V1. This implies that the age of blindness onset may exert significant effects on the development of cortical thickness of the V1. However, no previous research used a trajectory of the age of blindness onset-related changes to investigate these effects. Here we explored this issue by mapping the cortical thickness trajectory of the V1 against the age of blindness onset using data from 99 blind individuals whose age of blindness onset ranged from birth to 34 years. We found that the cortical thickness of the V1 could be fitted well with a quadratic curve in both the left (F = 11.59, P = 3 × 10(-5)) and right hemispheres (F = 6.54, P = 2 × 10(-3)). Specifically, the cortical thickness of the V1 thinned rapidly during childhood and adolescence and did not change significantly thereafter. This trend was not observed in the primary auditory cortex (A1), primary motor cortex (M1), or primary somatosensory cortex (S1). These results provide evidence that an onset of blindness before adulthood significantly affects the cortical thickness of the V1 and suggest a critical period for cortical development of the human V1.

  16. Demineralized Freeze-Dried Bovine Cortical Bone: Its Potential for Guided Bone Regeneration Membrane

    Directory of Open Access Journals (Sweden)

    David B. Kamadjaja

    2017-01-01

    Full Text Available Background. Bovine pericardium collagen membrane (BPCM had been widely used in guided bone regeneration (GBR whose manufacturing process usually required chemical cross-linking to prolong its biodegradation. However, cross-linking of collagen fibrils was associated with poorer tissue integration and delayed vascular invasion. Objective. This study evaluated the potential of bovine cortical bone collagen membrane for GBR by evaluating its antigenicity potential, cytotoxicity, immune and tissue response, and biodegradation behaviors. Material and Methods. Antigenicity potential of demineralized freeze-dried bovine cortical bone membrane (DFDBCBM was done with histology-based anticellularity evaluation, while cytotoxicity was analyzed using MTT Assay. Evaluation of immune response, tissue response, and biodegradation was done by randomly implanting DFDBCBM and BPCM in rat’s subcutaneous dorsum. Samples were collected at 2, 5, and 7 days and 7, 14, 21, and 28 days for biocompatibility and tissue response-biodegradation study, respectively. Result. DFDBCBM, histologically, showed no retained cells; however, it showed some level of in vitro cytotoxicity. In vivo study exhibited increased immune response to DFDBCBM in early healing phase; however, normal tissue response and degradation rate were observed up to 4 weeks after DFDBCBM implantation. Conclusion. Demineralized freeze-dried bovine cortical bone membrane showed potential for clinical application; however, it needs to be optimized in its biocompatibility to fulfill all requirements for GBR membrane.

  17. Positive association of video game playing with left frontal cortical thickness in adolescents.

    Directory of Open Access Journals (Sweden)

    Simone Kühn

    Full Text Available Playing video games is a common recreational activity of adolescents. Recent research associated frequent video game playing with improvements in cognitive functions. Improvements in cognition have been related to grey matter changes in prefrontal cortex. However, a fine-grained analysis of human brain structure in relation to video gaming is lacking. In magnetic resonance imaging scans of 152 14-year old adolescents, FreeSurfer was used to estimate cortical thickness. Cortical thickness across the whole cortical surface was correlated with self-reported duration of video gaming (hours per week. A robust positive association between cortical thickness and video gaming duration was observed in left dorsolateral prefrontal cortex (DLPFC and left frontal eye fields (FEFs. No regions showed cortical thinning in association with video gaming frequency. DLPFC is the core correlate of executive control and strategic planning which in turn are essential cognitive domains for successful video gaming. The FEFs are a key region involved in visuo-motor integration important for programming and execution of eye movements and allocation of visuo-spatial attention, processes engaged extensively in video games. The results may represent the biological basis of previously reported cognitive improvements due to video game play. Whether or not these results represent a-priori characteristics or consequences of video gaming should be studied in future longitudinal investigations.

  18. Positive association of video game playing with left frontal cortical thickness in adolescents.

    Science.gov (United States)

    Kühn, Simone; Lorenz, Robert; Banaschewski, Tobias; Barker, Gareth J; Büchel, Christian; Conrod, Patricia J; Flor, Herta; Garavan, Hugh; Ittermann, Bernd; Loth, Eva; Mann, Karl; Nees, Frauke; Artiges, Eric; Paus, Tomas; Rietschel, Marcella; Smolka, Michael N; Ströhle, Andreas; Walaszek, Bernadetta; Schumann, Gunter; Heinz, Andreas; Gallinat, Jürgen

    2014-01-01

    Playing video games is a common recreational activity of adolescents. Recent research associated frequent video game playing with improvements in cognitive functions. Improvements in cognition have been related to grey matter changes in prefrontal cortex. However, a fine-grained analysis of human brain structure in relation to video gaming is lacking. In magnetic resonance imaging scans of 152 14-year old adolescents, FreeSurfer was used to estimate cortical thickness. Cortical thickness across the whole cortical surface was correlated with self-reported duration of video gaming (hours per week). A robust positive association between cortical thickness and video gaming duration was observed in left dorsolateral prefrontal cortex (DLPFC) and left frontal eye fields (FEFs). No regions showed cortical thinning in association with video gaming frequency. DLPFC is the core correlate of executive control and strategic planning which in turn are essential cognitive domains for successful video gaming. The FEFs are a key region involved in visuo-motor integration important for programming and execution of eye movements and allocation of visuo-spatial attention, processes engaged extensively in video games. The results may represent the biological basis of previously reported cognitive improvements due to video game play. Whether or not these results represent a-priori characteristics or consequences of video gaming should be studied in future longitudinal investigations.

  19. Positive Association of Video Game Playing with Left Frontal Cortical Thickness in Adolescents

    Science.gov (United States)

    Kühn, Simone; Lorenz, Robert; Banaschewski, Tobias; Barker, Gareth J.; Büchel, Christian; Conrod, Patricia J.; Flor, Herta; Garavan, Hugh; Ittermann, Bernd; Loth, Eva; Mann, Karl; Nees, Frauke; Artiges, Eric; Paus, Tomas; Rietschel, Marcella; Smolka, Michael N.; Ströhle, Andreas; Walaszek, Bernadetta; Schumann, Gunter; Heinz, Andreas; Gallinat, Jürgen

    2014-01-01

    Playing video games is a common recreational activity of adolescents. Recent research associated frequent video game playing with improvements in cognitive functions. Improvements in cognition have been related to grey matter changes in prefrontal cortex. However, a fine-grained analysis of human brain structure in relation to video gaming is lacking. In magnetic resonance imaging scans of 152 14-year old adolescents, FreeSurfer was used to estimate cortical thickness. Cortical thickness across the whole cortical surface was correlated with self-reported duration of video gaming (hours per week). A robust positive association between cortical thickness and video gaming duration was observed in left dorsolateral prefrontal cortex (DLPFC) and left frontal eye fields (FEFs). No regions showed cortical thinning in association with video gaming frequency. DLPFC is the core correlate of executive control and strategic planning which in turn are essential cognitive domains for successful video gaming. The FEFs are a key region involved in visuo-motor integration important for programming and execution of eye movements and allocation of visuo-spatial attention, processes engaged extensively in video games. The results may represent the biological basis of previously reported cognitive improvements due to video game play. Whether or not these results represent a-priori characteristics or consequences of video gaming should be studied in future longitudinal investigations. PMID:24633348

  20. Aging and Fracture of Human Cortical Bone and Tooth Dentin

    Energy Technology Data Exchange (ETDEWEB)

    Ager, Joel; Koester, Kurt J.; Ager III, Joel W.; Ritchie, Robert O.

    2008-05-07

    Mineralized tissues, such as bone and tooth dentin, serve as structural materials in the human body and, as such, have evolved to resist fracture. In assessing their quantitative fracture resistance or toughness, it is important to distinguish between intrinsic toughening mechanisms which function ahead of the crack tip, such as plasticity in metals, and extrinsic mechanisms which function primarily behind the tip, such as crack bridging in ceramics. Bone and dentin derive their resistance to fracture principally from extrinsic toughening mechanisms which have their origins in the hierarchical microstructure of these mineralized tissues. Experimentally, quantification of these toughening mechanisms requires a crack-growth resistance approach, which can be achieved by measuring the crack-driving force, e.g., the stress intensity, as a function of crack extension ("R-curve approach"). Here this methodology is used to study of the effect of aging on the fracture properties of human cortical bone and human dentin in order to discern the microstructural origins of toughness in these materials.

  1. Dynamic Development of Regional Cortical Thickness and Surface Area in Early Childhood.

    Science.gov (United States)

    Lyall, Amanda E; Shi, Feng; Geng, Xiujuan; Woolson, Sandra; Li, Gang; Wang, Li; Hamer, Robert M; Shen, Dinggang; Gilmore, John H

    2015-08-01

    Cortical thickness (CT) and surface area (SA) are altered in many neuropsychiatric disorders and are correlated with cognitive functioning. Little is known about how these components of cortical gray matter develop in the first years of life. We studied the longitudinal development of regional CT and SA expansion in healthy infants from birth to 2 years. CT and SA have distinct and heterogeneous patterns of development that are exceptionally dynamic; overall CT increases by an average of 36.1%, while cortical SA increases 114.6%. By age 2, CT is on average 97% of adult values, compared with SA, which is 69%. This suggests that early identification, prevention, and intervention strategies for neuropsychiatric illness need to be targeted to this period of rapid postnatal brain development, and that SA expansion is the principal driving factor in cortical volume after 2 years of age.

  2. The role of aerobic fitness in cortical thickness and mathematics achievement in preadolescent children.

    Science.gov (United States)

    Chaddock-Heyman, Laura; Erickson, Kirk I; Kienzler, Caitlin; King, Matthew; Pontifex, Matthew B; Raine, Lauren B; Hillman, Charles H; Kramer, Arthur F

    2015-01-01

    Growing evidence suggests that aerobic fitness benefits the brain and cognition during childhood. The present study is the first to explore cortical brain structure of higher fit and lower fit 9- and 10-year-old children, and how aerobic fitness and cortical thickness relate to academic achievement. We demonstrate that higher fit children (>70th percentile VO2max) showed decreased gray matter thickness in superior frontal cortex, superior temporal areas, and lateral occipital cortex, coupled with better mathematics achievement, compared to lower fit children (achievement, particularly mathematics achievement, and raise the possibility that individual differences in aerobic fitness play an important role in cortical gray matter thinning during brain maturation. The establishment of predictors of academic performance is key to helping educators focus on interventions to maximize learning and success across the lifespan.

  3. Long bone histology of the subterranean rodent Bathyergus suillus (Bathyergidae): ontogenetic pattern of cortical bone thickening.

    Science.gov (United States)

    Montoya-Sanhueza, Germán; Chinsamy, Anusuya

    2017-02-01

    Patterns of bone development in mammals are best known from terrestrial and cursorial groups, but there is a considerable gap in our understanding of how specializations for life underground affect bone growth and development. Likewise, studies of bone microstructure in wild populations are still scarce, and they often include few individuals and tend to be focused on adults. For these reasons, the processes generating bone microstructural variation at intra- and interspecific levels are not fully understood. This study comprehensively examines the bone microstructure of an extant population of Cape dune molerats, Bathyergus suillus (Bathyergidae), the largest subterranean mammal endemic to the Western Cape of South Africa. The aim of this study is to investigate the postnatal bone growth of B. suillus using undecalcified histological sections (n = 197) of the femur, humerus, tibia-fibula, ulna and radius, including males and females belonging to different ontogenetic and reproductive stages (n = 42). Qualitative histological features demonstrate a wide histodiversity with thickening of the cortex mainly resulting from endosteal and periosteal bone depositions, whilst there is scarce endosteal resorption and remodeling throughout ontogeny. This imbalanced bone modeling allows the tissues deposited during ontogeny to remain relatively intact, thus preserving an excellent record of growth. The distribution of the different bone tissues observed in the cortex depends on ontogenetic status, anatomical features (e.g. muscle attachment structures) and location on the bone (e.g. anterior or lateral). The type of bone microstructure and modeling is discussed in relation to digging behavior, reproduction and physiology of this species. This study is the first histological assessment describing the process of cortical thickening in long bones of a fossorial mammal.

  4. Cortical thickness and prosocial behavior in school-age children: A population-based MRI study.

    Science.gov (United States)

    Thijssen, Sandra; Wildeboer, Andrea; Muetzel, Ryan L; Bakermans-Kranenburg, Marian J; El Marroun, Hanan; Hofman, Albert; Jaddoe, Vincent W V; van der Lugt, Aad; Verhulst, Frank C; Tiemeier, Henning; van IJzendoorn, Marinus H; White, Tonya

    2015-01-01

    Prosocial behavior plays an important role in establishing and maintaining relationships with others and thus may have important developmental implications. This study examines the association between cortical thickness and prosocial behavior in a population-based sample of 6- to 9-year-old children. The present study was embedded within the Generation R Study. Magnetic resonance scans were acquired from 464 children whose parents had completed the prosocial scale of the Strengths and Difficulties Questionnaire. To study the association between cortical thickness and prosocial behavior, we performed whole-brain surface-based analyses. Prosocial behavior was related to a thicker cortex in a cluster that covers part of the left superior frontal and rostral middle frontal cortex (p prosocial behavior and cortical thickness in a cluster including the right rostral middle frontal and superior frontal cortex (p prosocial behavior is associated with cortical thickness in regions related to theory of mind (superior frontal cortex, rostral middle frontal cortex cuneus, and precuneus) and inhibitory control (superior frontal and rostral middle frontal cortex).

  5. Reduced cortical thickness of brain areas involved in pain processing in patients with chronic pancreatitis.

    NARCIS (Netherlands)

    Frokjaer, J.B.; Bouwense, S.A.W.; Olesen, S.S.; Lundager, F.H.; Eskildsen, S.F.; Goor, H. van; Wilder-Smith, O.H.G.; Drewes, A.M.

    2012-01-01

    BACKGROUND & AIMS: Patients with painful chronic pancreatitis (CP) might have abnormal brain function. We assessed cortical thickness in brain areas involved in visceral pain processing. METHODS: We analyzed brain morphologies of 19 patients with painful CP and compared them with 15 healthy individu

  6. Impaired response inhibition and excess cortical thickness as candidate endophenotypes for trichotillomania

    DEFF Research Database (Denmark)

    Odlaug, Brian Lawrence; Chamberlain, Samuel R; Derbyshire, Katie L

    2014-01-01

    occupying an intermediate position. Permutation cluster analysis revealed significant excesses of cortical thickness in patients and their relatives compared to controls, in right inferior/middle frontal gyri (Brodmann Area, BA 47 & 11), right lingual gyrus (BA 18), left superior temporal cortex (BA 21...

  7. Age of language learning shapes brain structure: a cortical thickness study of bilingual and monolingual individuals.

    Science.gov (United States)

    Klein, Denise; Mok, Kelvin; Chen, Jen-Kai; Watkins, Kate E

    2014-04-01

    We examined the effects of learning a second language (L2) on brain structure. Cortical thickness was measured in the MRI datasets of 22 monolinguals and 66 bilinguals. Some bilingual subjects had learned both languages simultaneously (0-3 years) while some had learned their L2 after achieving proficiency in their first language during either early (4-7 years) or late childhood (8-13 years). Later acquisition of L2 was associated with significantly thicker cortex in the left inferior frontal gyrus (IFG) and thinner cortex in the right IFG. These effects were seen in the group comparisons of monolinguals, simultaneous bilinguals and early and late bilinguals. Within the bilingual group, significant correlations between age of acquisition of L2 and cortical thickness were seen in the same regions: cortical thickness correlated with age of acquisition positively in the left IFG and negatively in the right IFG. Interestingly, the monolinguals and simultaneous bilinguals did not differ in cortical thickness in any region. Our results show that learning a second language after gaining proficiency in the first language modifies brain structure in an age-dependent manner whereas simultaneous acquisition of two languages has no additional effect on brain development.

  8. Brain volumes and regional cortical thickness in young females with anorexia nervosa.

    Science.gov (United States)

    Fuglset, Tone Seim; Endestad, Tor; Hilland, Eva; Bang, Lasse; Tamnes, Christian Krog; Landrø, Nils Inge; Rø, Øyvind

    2016-11-16

    Anorexia nervosa (AN) is a severe mental illness, with an unknown etiology. Magnetic resonance imaging studies show reduced brain volumes and cortical thickness in patients compared to healthy controls. However, findings are inconsistent, especially concerning the anatomical location and extent of the differences. The purpose of this study was to estimate and compare brain volumes and regional cortical thickness in young females with AN and healthy controls. Magnetic resonance imaging data was acquired from young females with anorexia nervosa (n = 23) and healthy controls (n = 28). Two different scanner sites were used. BMI varied from 13.5 to 20.7 within the patient group, and 11 patients had a BMI > 17.5. FreeSurfer was used to estimate brain volumes and regional cortical thickness. There were no differences between groups in total cerebral cortex volume, white matter volume, or lateral ventricle volume. There were also no volume differences in subcortical grey matter structures. However the results showed reduced cortical thickness bilaterally in the superior parietal gyrus, and in the right inferior parietal and superior frontal gyri. The functional significance of the findings is undetermined as the majority of the included patients was already partially weight-restored. We discuss whether these regions could be related to predisposing factors of the illness, or whether they are regions that are more vulnerable to starvation, malnutrition or associated processes in AN.

  9. Cortical thickness in individuals with non-clinical and clinical psychotic symptoms

    NARCIS (Netherlands)

    van Lutterveld, Remko; van den Heuvel, Martijn P.; Diederen, Kelly M. J.; de Weijer, Antoin D.; Begemann, Marieke J. H.; Brouwer, Rachel M.; Daalman, Kirstin; Blom, Jan Dirk; Kahn, Rene S.; Sommer, Iris E.

    2014-01-01

    Symptoms that are linked to psychosis are also experienced by individuals who are not in need of care. In the present study, cortical thickness was investigated in these individuals. Fifty individuals with non-clinical auditory verbal hallucinations (most of them also experienced other non-clinical

  10. Scanning electron microscopy of human cortical bone failure surfaces.

    Science.gov (United States)

    Braidotti, P; Branca, F P; Stagni, L

    1997-02-01

    Undecalcified samples extracted from human femoral shafts are fractured by bending and the fracture surfaces are examined with a scanning electron microscope (SEM). The investigation is performed on both dry and wet (hydrated with a saline solution) specimens. SEM micrographs show patterns in many respects similar to those observed in fractography studies of laminated fiber-reinforced synthetic composites. In particular, dry and wet samples behave like brittle and ductile matrix laminates, respectively. An analysis carried out on the basis of the mechanisms that dominate the fracture process of laminates shows that a reasonable cortical bone model is that of a laminated composite material whose matrix is composed of extracellular noncollagenous calcified proteins, and the reinforcement is constituted by the calcified collagen fiber system.

  11. Effects of lithium on cortical thickness and hippocampal subfield volumes in psychotic bipolar disorder.

    Science.gov (United States)

    Giakoumatos, C I; Nanda, P; Mathew, I T; Tandon, N; Shah, J; Bishop, J R; Clementz, B A; Pearlson, G D; Sweeney, J A; Tamminga, C A; Keshavan, M S

    2015-02-01

    Relative to healthy controls, lithium free bipolar patients exhibit significant gray matter abnormalities. Lithium, the long-time reference standard medication treatment for bipolar disorder, has been proposed to be neuro-protective against these abnormalities. However, its effects on cortical thickness and hippocampal subfield (HSF) volumes remain unstudied and unclear, respectively, in bipolar disorder. This study included 342 healthy controls (HC), 51 lithium free PBD patients (NoLi), and 51 PBD patients taking lithium (Li). Regional gray matter thickness and HSF volume values were extracted from 3T MRI images. After matching NoLi and Li samples, regions where HC differed from either Li or NoLi were identified. In regions of significant or trending HC-NoLi difference, Li-NoLi comparisons were made. No significant HC-Li thickness or HSF volume differences were found. Significantly thinner occipital cortices were observed in NoLi compared to HC. In these regions, Li consistently exhibited non-significant trends for greater cortical thickness relative to NoLi. Significantly less volume was observed in NoLi compared to both HC and Li in right HSFs. Our results suggest that PBD in patients not treated with Li is associated with thinner occipital cortices and reduced HSF volumes compared with HC. Patients treated with Li exhibited significantly larger HSF volumes than NoLi, and those treated with Li were no different from HC in cortical thickness or hippocampal volumes. This evidence directly supports the hypothesis that Li may counteract the locally thinner and smaller gray matter structure found in PBD. Copyright © 2014. Published by Elsevier Ltd.

  12. Cancellous Screws Are Biomechanically Superior to Cortical Screws in Metaphyseal Bone.

    Science.gov (United States)

    Wang, Tim; Boone, Christopher; Behn, Anthony W; Ledesma, Justin B; Bishop, Julius A

    2016-09-01

    Cancellous screws are designed to optimize fixation in metaphyseal bone environments; however, certain clinical situations may require the substitution of cortical screws for use in cancellous bone, such as anatomic constraints, fragment size, or available instrumentation. This study compares the biomechanical properties of commercially available cortical and cancellous screw designs in a synthetic model representing various bone densities. Commercially available, fully threaded, 4.0-mm outer-diameter cortical and cancellous screws were tested in terms of pullout strength and maximum insertion torque in standard-density and osteoporotic cancellous bone models. Pullout strength and maximum insertion torque were both found to be greater for cancellous screws than cortical screws in all synthetic densities tested. The magnitude of difference in pullout strength between cortical and cancellous screws increased with decreasing synthetic bone density. Screw displacement prior to failure and total energy absorbed during pullout strength testing were also significantly greater for cancellous screws in osteoporotic models. Stiffness was greater for cancellous screws in standard and osteoporotic models. Cancellous screws have biomechanical advantages over cortical screws when used in metaphyseal bone, implying the ability to both achieve greater compression and resist displacement at the screw-plate interface. Surgeons should preferentially use cancellous over cortical screws in metaphyseal environments where cortical bone is insufficient for fixation. [Orthopedics.2016; 39(5):e828-e832.].

  13. Computed tomography analysis of guinea pig bone: architecture, bone thickness and dimensions throughout development.

    Science.gov (United States)

    Witkowska, Agata; Alibhai, Aziza; Hughes, Chloe; Price, Jennifer; Klisch, Karl; Sturrock, Craig J; Rutland, Catrin S

    2014-01-01

    The domestic guinea pig, Cavia aperea f. porcellus, belongs to the Caviidae family of rodents. It is an important species as a pet, a source of food and in medical research. Adult weight is achieved at 8-12 months and life expectancy is ∼5-6 years. Our aim was to map bone local thickness, structure and dimensions across developmental stages in the normal animal. Guinea pigs (n = 23) that had died of natural causes were collected and the bones manually extracted and cleaned. Institutional ethical permission was given under the UK Home Office guidelines and the Veterinary Surgeons Act. X-ray Micro Computed Tomography (microCT) was undertaken on the left and right scapula, humerus and femur from each animal to ascertain bone local thickness. Images were also used to undertake manual and automated bone measurements, volumes and surface areas, identify and describe nutrient, supratrochlear and supracondylar foramina. Statistical analysis between groups was carried out using ANOVA with post-hoc testing. Our data mapped a number of dimensions, and mean and maximum bone thickness of the scapula, humerus and femur in guinea pigs aged 0-1 month, 1-3 months, 3-6 months, 6 months-1 year and 1-4 years. Bone dimensions, growth rates and local bone thicknesses differed between ages and between the scapula, humerus and femur. The microCT and imaging software technology showed very distinct differences between the relative local bone thickness across the structure of the bones. Only one bone showed a singular nutrient foramen, every other bone had between 2 and 5, and every nutrient canal ran in an oblique direction. In contrast to other species, a supratrochlear foramen was observed in every humerus whereas the supracondylar foramen was always absent. Our data showed the bone local thickness, bone structure and measurements of guinea pig bones from birth to 4 years old. Importantly it showed that bone development continued after 1 year, the point at which most guinea pigs have

  14. Computed tomography analysis of guinea pig bone: architecture, bone thickness and dimensions throughout development

    Directory of Open Access Journals (Sweden)

    Agata Witkowska

    2014-10-01

    Full Text Available The domestic guinea pig, Cavia aperea f. porcellus, belongs to the Caviidae family of rodents. It is an important species as a pet, a source of food and in medical research. Adult weight is achieved at 8–12 months and life expectancy is ∼5–6 years. Our aim was to map bone local thickness, structure and dimensions across developmental stages in the normal animal. Guinea pigs (n = 23 that had died of natural causes were collected and the bones manually extracted and cleaned. Institutional ethical permission was given under the UK Home Office guidelines and the Veterinary Surgeons Act. X-ray Micro Computed Tomography (microCT was undertaken on the left and right scapula, humerus and femur from each animal to ascertain bone local thickness. Images were also used to undertake manual and automated bone measurements, volumes and surface areas, identify and describe nutrient, supratrochlear and supracondylar foramina. Statistical analysis between groups was carried out using ANOVA with post-hoc testing. Our data mapped a number of dimensions, and mean and maximum bone thickness of the scapula, humerus and femur in guinea pigs aged 0–1 month, 1–3 months, 3–6 months, 6 months–1 year and 1–4 years. Bone dimensions, growth rates and local bone thicknesses differed between ages and between the scapula, humerus and femur. The microCT and imaging software technology showed very distinct differences between the relative local bone thickness across the structure of the bones. Only one bone showed a singular nutrient foramen, every other bone had between 2 and 5, and every nutrient canal ran in an oblique direction. In contrast to other species, a supratrochlear foramen was observed in every humerus whereas the supracondylar foramen was always absent. Our data showed the bone local thickness, bone structure and measurements of guinea pig bones from birth to 4 years old. Importantly it showed that bone development continued after 1 year, the point

  15. In vivo monitoring of bone architecture and remodeling after implant insertion: The different responses of cortical and trabecular bone.

    Science.gov (United States)

    Li, Zihui; Kuhn, Gisela; von Salis-Soglio, Marcella; Cooke, Stephen J; Schirmer, Michael; Müller, Ralph; Ruffoni, Davide

    2015-12-01

    The mechanical integrity of the bone-implant system is maintained by the process of bone remodeling. Specifically, the interplay between bone resorption and bone formation is of paramount importance to fully understand the net changes in bone structure occurring in the peri-implant bone, which are eventually responsible for the mechanical stability of the bone-implant system. Using time-lapsed in vivo micro-computed tomography combined with new composite material implants, we were able to characterize the spatio-temporal changes of bone architecture and bone remodeling following implantation in living mice. After insertion, implant stability was attained by a quick and substantial thickening of the cortical shell which counteracted the observed loss of trabecular bone, probably due to the disruption of the trabecular network. Within the trabecular compartment, the rate of bone formation close to the implant was transiently higher than far from the implant mainly due to an increased mineral apposition rate which indicated a higher osteoblastic activity. Conversely, in cortical bone, the higher rate of bone formation close to the implant compared to far away was mostly related to the recruitment of new osteoblasts as indicated by a prevailing mineralizing surface. The behavior of bone resorption also showed dissimilarities between trabecular and cortical bone. In the former, the rate of bone resorption was higher in the peri-implant region and remained elevated during the entire monitoring period. In the latter, bone resorption rate had a bigger value away from the implant and decreased with time. Our approach may help to tune the development of smart implants that can attain a better long-term stability by a local and targeted manipulation of the remodeling process within the cortical and the trabecular compartments and, particularly, in bone of poor health.

  16. Time-lapsed assessment of microcrack initiation and propagation in murine cortical bone at submicrometer resolution.

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    Voide, R; Schneider, P; Stauber, M; Wyss, P; Stampanoni, M; Sennhauser, U; van Lenthe, G H; Müller, R

    2009-08-01

    The strength of bone tissue is not only determined by its mass, but also by other properties usually referred to as bone quality, such as microarchitecture, distribution of bone cells, or microcracks and damage. It has been hypothesized that the bone ultrastructure affects microcrack initiation and propagation. Due to its high resolution, bone assessment by means of synchrotron radiation (SR)-based computed tomography (CT) allows unprecedented three-dimensional (3D) and non-invasive insights into ultrastructural bone phenotypes, such as the canal network and the osteocyte lacunar system. The aims of this study were to describe the initiation and propagation of microcracks and their relation with these ultrastructural phenotypes. To this end, femora from the two genetically distinct inbred mouse strains C3H/He (C3H) and C57BL/6 (B6) were loaded axially under compression, from 0% strain to failure, with 1% strain steps. Between each step, a high-resolution 3D image (700 nm nominal resolution) was acquired at the mid-diaphysis using SR CT for characterization and quantitative analysis of the intracortical porosity, namely the bone canal network, the osteocyte lacunar system and the emerging microcracks. For C3H mice, the canal, lacunar, and microcrack volume densities accounted typically for 1.91%, 2.11%, and 0.27% of the cortical total volume at 2% apparent strain, respectively. Due to its 3D nature, SR CT allowed to visualize and quantify also the volumetric extent of microcracks. At 2% apparent strain, the average microcrack thickness for both mouse strains was 2.0 microm for example. Microcracks initiated at canal and at bone surfaces, whereas osteocyte lacunae provided guidance to the microcracks. Moreover, we observed that microcracks could appear as linear cracks in one plane, but as diffuse cracks in a perpendicular plane. Finally, SR CT images permitted visualization of uncracked ligament bridging, which is thought to be of importance in bone toughening

  17. Cortical Thickness Changes Correlate with Cognition Changes after Cognitive Training: Evidence from a Chinese Community Study.

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    Jiang, Lijuan; Cao, Xinyi; Li, Ting; Tang, Yingying; Li, Wei; Wang, Jijun; Chan, Raymond C; Li, Chunbo

    2016-01-01

    The aim of this study was to investigate whether changes in cortical thickness correlated with cognitive function changes in healthy older adults after receiving cognitive training interventions. Moreover, it also aimed to examine the differential impacts of a multi-domain and a single-domain cognitive training interventions. Longitudinal magnetic resonance imaging (MRI) scanning was performed on participants 65-75 years of age using the Siemens 3.0 T Trio Tim with the Magnetization Prepared Rapid Gradient Echo (MPRAGE) sequence. The cortical thickness was determined using FreeSurfer Software. Cognitive functioning was evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). There were significant group × time interaction effects on the left supramarginal, the left frontal pole cortical regions; and a marginal significant group × time interaction effects on visuospatial/constructional and delayed memory scores. In a multi-domain cognitive training group, a number of cortical region changes were significantly positively correlated with changes in attention, delayed memory, and the total score, but significantly negatively correlated with changes in immediate memory and language scores. In the single-domain cognitive training group, some cortical region changes were significantly positively associated with changes in immediate memory, delayed memory, and the total score, while they were significantly negatively associated with changes in visuospatial/constructional, language, and attention scores. Overall, multi-domain cognitive training offered more advantages in visuospatial/constructional, attention, and delayed memory abilities, while single-domain cognitive training benefited immediate memory ability more effectively. These findings suggest that healthy older adults benefit more from the multi-domain cognitive training than single-domain cognitive training. Cognitive training has impacted on cortical thickness changes in

  18. Cortical thickness correlates of socioemotional difficulties in adults with Turner syndrome.

    Science.gov (United States)

    Lepage, Jean-François; Clouchoux, Cédric; Lassonde, Maryse; Evans, Alan C; Deal, Cheri L; Théoret, Hugo

    2014-06-01

    Turner syndrome (TS) is a non-inherited genetic disorder associated with a specific cognitive phenotype and socioemotional impairments. The present study aimed at characterizing the neuroanatomical basis of socioemotional dysfunctions in TS using the Emotional Quotient inventory (EQ-I) and cortical morphology analysis in 17 individuals with TS (45,X) and 17-age and verbal IQ matched healthy females. Individuals with TS reported significantly greater socioemotional impairment than controls. Cortical thickness analysis showed that participants with TS had an overall thicker cortex than controls, with extensive alterations in the temporal, frontal, parietal and insular regions bilaterally. Using the total EQ-I score as regressor in the cortical thickness analysis revealed a number of brain regions where the relationship between cortical thickness and EQ-I score differed between groups; these areas included brain regions critically involved in socioemotional processes, such as bilateral insula, the anterior cingulate and the orbitofrontal cortex. These results show that socioemotional dysfunctions seen in women with TS are associated with significant alterations in brain morphology.

  19. Prediction of brain maturity based on cortical thickness at different spatial resolutions.

    Science.gov (United States)

    Khundrakpam, Budhachandra S; Tohka, Jussi; Evans, Alan C

    2015-05-01

    Several studies using magnetic resonance imaging (MRI) scans have shown developmental trajectories of cortical thickness. Cognitive milestones happen concurrently with these structural changes, and a delay in such changes has been implicated in developmental disorders such as attention-deficit/hyperactivity disorder (ADHD). Accurate estimation of individuals' brain maturity, therefore, is critical in establishing a baseline for normal brain development against which neurodevelopmental disorders can be assessed. In this study, cortical thickness derived from structural magnetic resonance imaging (MRI) scans of a large longitudinal dataset of normally growing children and adolescents (n=308), were used to build a highly accurate predictive model for estimating chronological age (cross-validated correlation up to R=0.84). Unlike previous studies which used kernelized approach in building prediction models, we used an elastic net penalized linear regression model capable of producing a spatially sparse, yet accurate predictive model of chronological age. Upon investigating different scales of cortical parcellation from 78 to 10,240 brain parcels, we observed that the accuracy in estimated age improved with increased spatial scale of brain parcellation, with the best estimations obtained for spatial resolutions consisting of 2560 and 10,240 brain parcels. The top predictors of brain maturity were found in highly localized sensorimotor and association areas. The results of our study demonstrate that cortical thickness can be used to estimate individuals' brain maturity with high accuracy, and the estimated ages relate to functional and behavioural measures, underscoring the relevance and scope of the study in the understanding of biological maturity.

  20. Age effects on cortical thickness in young Down's syndrome subjects: a cross-sectional gender study

    Energy Technology Data Exchange (ETDEWEB)

    Romano, Andrea; Moraschi, Marta [San Raffaele Foundation Rome, Rehabilitation Facility Ceglie Messapica, Rome (Italy); Cornia, Riccardo; Stella, Giacomo [University of Modena and Reggio Emilia, Department of Education and Human Sciences, Emilia-Romagna (Italy); Bozzao, Alessandro; Gagliardo, Olga [University Sapienza, NESMOS, Department of Neuroradiology, S. Andrea Hospital, Rome (Italy); Chiacchiararelli, Laura [University Sapienza, Department of Medical Physics, S. Andrea Hospital, Rome (Italy); Iani, Cristina [University of Modena and Reggio Emilia, Department of Communication and Economy, Emilia-Romagna (Italy); Albertini, Giorgio [IRCSS San Raffaele Pisana, Department of Paediatrics, Rome (Italy); Pierallini, Alberto [IRCSS San Raffaele Pisana, Department of Radiology, Rome (Italy)

    2015-04-01

    The aim of this study was to determine differences in the characteristic pattern of age-related cortical thinning in men and women with Down's syndrome (DS) by means of MRI and automatic cortical thickness measurements and a cross-sectional design, in a large cohort of young subjects. Eighty-four subjects with DS, 30 females (11-35 years, mean age ± SD = 22.8 ± 5.9) and 54 males (11-35 years, mean age ± SD = 21.5 ± 6.5), were examined using a 1.5-T scanner. MRI-based quantification of cortical thickness was performed using FreeSurfer software package. For all subjects participating in the study, the Pearson product-moment correlation coefficient between age and mean cortical thickness values has been evaluated. A significant negative correlation between cortical thickness and age was found in female DS subjects, predominantly in frontal and parietal lobes, bilaterally. In male DS subjects, a significant negative correlation between cortical thickness and age was found in the right fronto-temporal lobes and cingulate regions. Whole brain mean cortical thickness values were significantly negative correlated with age only in female DS subjects. Females with Down's syndrome showed a strong correlation between cortical thickness and age, already in early age. We suggest that the cognitive impairment due to hormonal deficit in the postmenopausal period could be emphasized by the early structural decline of gray matter in female DS subjects. (orig.)

  1. High Insulin Levels in KK-Ay Diabetic Mice Cause Increased Cortical Bone Mass and Impaired Trabecular Micro-Structure

    Directory of Open Access Journals (Sweden)

    Cen Fu

    2015-04-01

    Full Text Available Type 2 diabetes mellitus (T2DM is a chronic disease characterized by hyperglycemia, hyperinsulinemia and complications, including obesity and osteoporosis. Rodents have been widely used to model human T2DM and investigate its effect on the skeleton. We aimed to investigate skeletal alterations in Yellow Kuo Kondo (KK-Ay diabetic mice displaying high insulin and glucose levels. Bone mineral density (BMD, micro-architecture and bone metabolism-related genes were analyzed. The total femoral areal BMD (aBMD, cortical volumetric BMD (vBMD and thickness were significantly increased in KK-Ay mice, while the trabecular vBMD and mineralized bone volume/tissue volume (BV/TV, trabecular thickness and number were decreased compared to C57BL mice. The expression of both osteoblast-related genes, such as osteocalcin (OC, bone sialoprotein, Type I Collagen, osteonectin, RUNX2 and OSX, and osteoclast-related genes, such as TRAP and TCIRG, were up-regulated in KK-Ay mice. Correlation analyses showed that serum insulin levels were positively associated with aBMD, cortical vBMD and thickness and negatively associated with trabecular vBMD and micro-architecture. In addition, serum insulin levels were positively related to osteoblast-related and osteoclast-related gene expression. Our data suggest that high insulin levels in KK-Ay diabetic mice may increase cortical bone mass and impair trabecular micro-structure by up-regulating osteoblast-and osteoclast-related gene expression.

  2. Increased cortical thickness in a frontoparietal network in social anxiety disorder.

    Science.gov (United States)

    Brühl, Annette Beatrix; Hänggi, Jürgen; Baur, Volker; Rufer, Michael; Delsignore, Aba; Weidt, Steffi; Jäncke, Lutz; Herwig, Uwe

    2014-07-01

    Social anxiety disorder (SAD) is the second leading anxiety disorder. On the functional neurobiological level, specific brain regions involved in the processing of anxiety-laden stimuli and in emotion regulation have been shown to be hyperactive and hyper-responsive in SAD such as amygdala, insula and orbito- and prefrontal cortex. On the level of brain structure, prior studies on anatomical differences in SAD resulted in mixed and partially contradictory findings. Based on previous functional and anatomical models of SAD, this study examined cortical thickness in structural magnetic resonance imaging data of 46 patients with SAD without comorbidities (except for depressed episode in one patient) compared with 46 matched healthy controls in a region of interest-analysis and in whole-brain. In a theory-driven ROI-analysis, cortical thickness was increased in SAD in left insula, right anterior cingulate and right temporal pole. Furthermore, the whole-brain analysis revealed increased thickness in right dorsolateral prefrontal and right parietal cortex. This study detected no regions of decreased cortical thickness or brain volume in SAD. From the perspective of brain networks, these findings are in line with prior functional differences in salience networks and frontoparietal networks associated with executive-controlling and attentional functions.

  3. Cortical and trabecular bone at the forearm show different adaptation patterns in response to tennis playing.

    Science.gov (United States)

    Ducher, Gaële; Prouteau, Stéphanie; Courteix, Daniel; Benhamou, Claude-Laurent

    2004-01-01

    Bone responds to impact-loading activity by increasing its size and/or density. The aim of this study was to compare the magnitude and modality of the bone response between cortical and trabecular bone in the forearms of tennis players. Bone area, bone mineral content (BMC), and bone mineral density (BMD) of the ulna and radius were measured by dual-energy X-ray absorptiometry (DXA) in 57 players (24.5 +/- 5.7 yr old), at three sites: the ultradistal region (50% trabecular bone), the mid-distal regions, and third-distal (mainly cortical bone). At the ultradistal radius, the side-to-side difference in BMD was larger than in bone area (8.4 +/- 5.2% and 4.9 +/- 4.0%, respectively, p < 0.01). In the cortical sites, the asymmetry was lower (p < 0.01) in BMD than in bone area (mid-distal radius: 4.0 +/- 4.3% vs 11.7 +/- 6.8%; third-distal radius: 5.0 +/- 4.8% vs 8.4 +/- 6.2%). The asymmetry in bone area explained 33% of the variance of the asymmetry in BMC at the ultradistal radius, 66% at the mid-distal radius, and 53% at the third-distal radius. The ulna displayed similar results. Cortical and trabecular bone seem to respond differently to mechanical loading. The first one mainly increases its size, whereas the second one preferentially increases its density.

  4. Family History of Alzheimer's Disease and Cortical Thickness in Patients With Dementia.

    Science.gov (United States)

    Ganske, Steffi; Haussmann, Robert; Gruschwitz, Antonia; Werner, Annett; Osterrath, Antje; Baumgaertel, Johanna; Lange, Jan; Donix, Katharina L; Linn, Jennifer; Donix, Markus

    2016-08-01

    A first-degree family history of Alzheimer's disease reflects genetic risks for the neurodegenerative disorder. Recent imaging data suggest localized effects of genetic risks on brain structure in healthy people. It is unknown whether this association can also be found in patients who already have dementia. Our aim was to investigate whether family history risk modulates regional medial temporal lobe cortical thickness in patients with Alzheimer's disease. We performed high-resolution magnetic resonance imaging and cortical unfolding data analysis on 54 patients and 53 nondemented individuals. A first-degree family history of Alzheimer's disease was associated with left hemispheric cortical thinning in the subiculum among patients and controls. The contribution of Alzheimer's disease family history to regional brain anatomy changes independent of cognitive impairment may reflect genetic risks that modulate onset and clinical course of the disease.

  5. Cortical lamina technique: A therapeutic approach for lateral ridge augmentation using guided bone regeneration

    Science.gov (United States)

    Thomas, Raison; Baron, Tarun-Kumar; Shah, Rucha; Mehta, Dhoom-Singh

    2017-01-01

    Background The present study aimed at evaluating the efficacy of a novel technique, the bone lamina technique, in horizontal ridge augmentation clinically & radiographically using a combination of allogenic cortical shell, particulate xenograft and resorbable collagen membrane. Material and Methods Localized horizontal ridge defects, in ten patients (6 male, 4 female), with bucco-palatal ridge width less than 5 mm were included in this study. Localised ridge augmentation was performed using bone lamina technique with mineralised allogenic shell of 1 mm thickness trimmed to the appropriate size using stereo-lithographic models and fixed to the recipient site with stainless steel micro-screws of 1 mm diameter. The space between the shell & host bone was filled with particulate xenograft followed by placement of collagen membrane and primary closure of the site. Clinical parameters including ridge width before & after flap reflection & radiographic (CBCT) ridge width measurements were recorded pre-operatively,and six months after the augmentation procedure. Results obtained were analysed statistically. Results The mean clinical ridge width before flap reflection (BFR), after flap reflection (AFR) & radiographically was 3.7 ± 0.74 mm, 2 ± 0.70 mm & 1.77 ± 0.71 mm respectively at baseline which increased to 6.8 ± 0.95 mm, 5.15 ± 0.98 mm & 4.90 ± 0.90 mm with a mean gain in ridge width of 3.1 ± 0.63 mm (p< 0.005), 3.15 ± 0.63 mm (p<0.005) & 3.13 ± 0.70 mm (p< 0.005) respectively. Conclusions The present study demonstrates that bone lamina technique can be effective means of horizontal ridge augmentation and the use of mineralized allograft in combination with xenograft and collagen membrane leads to good amount of bone regeneration for subsequent implant placement. Key words:Dental implant, guided bone regeneration, horizontal ridge defect, ridge augmentation. PMID:28149458

  6. Humeral cortical thickness in female Bantu - its relationship to the incidence of femoral neck fracture

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, R.A.; Pogrund, H.

    1982-03-01

    Measurements of the humeral cortical thickness demonstrate that generalised osteoporosis in female Bantu commences in the fifth decade and gradually increases until, in the ninth decade, all subjects are osteoporotic. The combined cortical thickness (CCT) of the humerus in young adults is very similar to that found previously in a white London population and the loss of cortex with age is very similar. It is concluded that the known low incidence of femoral neck fracture in Bantu is not due to a lower incidence of generalised osteoporosis but to environmental factors. The chief environmental factor postulated is the greater amount of physical work performed by the Bantu. A more careful mode of walking is suggested as a subsidiary cause.

  7. Association of Optic Radiation Integrity with Cortical Thickness in Children with Anisometropic Amblyopia.

    Science.gov (United States)

    Qi, Shun; Mu, Yun-Feng; Cui, Long-Biao; Li, Rong; Shi, Mei; Liu, Ying; Xu, Jun-Qing; Zhang, Jian; Yang, Jian; Yin, Hong

    2016-02-01

    Previous studies have indicated regional abnormalities of both gray and white matter in amblyopia. However, alterations of cortical thickness associated with changes in white matter integrity have rarely been reported. In this study, structural magnetic resonance imaging and diffusion tensor imaging (DTI) data were obtained from 15 children with anisometropic amblyopia and 15 age- and gender-matched children with normal sight. Combining DTI and surface-based morphometry, we examined a potential linkage between disrupted white matter integrity and altered cortical thickness. The fractional anisotropy (FA) values in the optic radiations (ORs) of children with anisometropic amblyopia were lower than in controls (P amblyopia. These findings indicate that developmental changes occur simultaneously in the OR and visual cortex in amblyopia, and provide key information on complex damage of brain networks in anisometropic amblyopia. Our results also support the hypothesis that the pathogenesis of anisometropic amblyopia is neurodevelopmental.

  8. Relation of Childhood Home Environment to Cortical Thickness in Late Adolescence: Specificity of Experience and Timing.

    Science.gov (United States)

    Avants, Brian B; Hackman, Daniel A; Betancourt, Laura M; Lawson, Gwendolyn M; Hurt, Hallam; Farah, Martha J

    2015-01-01

    What are the long-term effects of childhood experience on brain development? Research with animals shows that the quality of environmental stimulation and parental nurturance both play important roles in shaping lifelong brain structure and function. Human research has so far been limited to the effects of abnormal experience and pathological development. Using a unique longitudinal dataset of in-home measures of childhood experience at ages 4 and 8 and MRI acquired in late adolescence, we were able to relate normal variation in childhood experience to later life cortical thickness. Environmental stimulation at age 4 predicted cortical thickness in a set of automatically derived regions in temporal and prefrontal cortex. In contrast, age 8 experience was not predictive. Parental nurturance was not predictive at either age. This work reveals an association between childhood experience and later brain structure that is specific relative to aspects of experience, regions of brain, and timing.

  9. Radiation-induced abnormal cortical thickness in patients with nasopharyngeal carcinoma after radiotherapy

    Directory of Open Access Journals (Sweden)

    Jiabao Lin

    2017-01-01

    Full Text Available Conventional MRI studies showed that radiation-induced brain necrosis in patients with nasopharyngeal carcinoma (NPC in years after radiotherapy (RT could involve brain gray matter (GM and impair brain function. However, it is still unclear the radiation-induced brain morphological changes in NPC patients with normal-appearing GM in the early period after RT. In this study, we acquired high-resolution brain structural MRI data from three groups of patients, 22 before radiotherapy (pre-RT NPC patients with newly diagnosed but not yet medically treated, 22 NPC patients in the early-delayed stage after radiotherapy (post-RT-ED, and 20 NPC patients in the late-delayed stage after radiotherapy (post-RT-LD, and then analyzed the radiation-induced cortical thickness alteration in NPC patients after RT. Using a vertex-wise surface-based morphometry (SBM approach, we detected significantly decreased cortical thickness in the precentral gyrus (PreCG in the post-RT-ED group compared to the pre-RT group. And the post-RT-LD group showed significantly increased cortical thickness in widespread brain regions, including the bilateral inferior parietal, left isthmus of the cingulate, left bank of the superior temporal sulcus and left lateral occipital regions, compared to the pre-RT group, and in the bilateral PreCG compared to the post-RT-ED group. Similar analysis with ROI-wise SBM method also found the consistent results. These results indicated that radiation-induced brain injury mainly occurred in the post-RT-LD group and the cortical thickness alterations after RT were dynamic in different periods. Our findings may reflect the pathogenesis of radiation-induced brain injury in NPC patients with normal-appearing GM and an early intervention is necessary for protecting GM during RT.

  10. Can we predict subject-specific dynamic cortical thickness maps during infancy from birth?

    Science.gov (United States)

    Meng, Yu; Li, Gang; Rekik, Islem; Zhang, Han; Gao, Yaozong; Lin, Weili; Shen, Dinggang

    2017-06-01

    Understanding the early dynamic development of the human cerebral cortex remains a challenging problem. Cortical thickness, as one of the most important morphological attributes of the cerebral cortex, is a sensitive indicator for both normal neurodevelopment and neuropsychiatric disorders, but its early postnatal development remains largely unexplored. In this study, we investigate a key question in neurodevelopmental science: can we predict the future dynamic development of cortical thickness map in an individual infant based on its available MRI data at birth? If this is possible, we might be able to better model and understand the early brain development and also early detect abnormal brain development during infancy. To this end, we develop a novel learning-based method, called Dynamically-Assembled Regression Forest (DARF), to predict the development of the cortical thickness map during the first postnatal year, based on neonatal MRI features. We applied our method to 15 healthy infants and predicted their cortical thickness maps at 3, 6, 9, and 12 months of age, with respectively mean absolute errors of 0.209 mm, 0.332 mm, 0.340 mm, and 0.321 mm. Moreover, we found that the prediction precision is region-specific, with high precision in the unimodal cortex and relatively low precision in the high-order association cortex, which may be associated with their differential developmental patterns. Additional experiments also suggest that using more early time points for prediction can further significantly improve the prediction accuracy. Hum Brain Mapp 38:2865-2874, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  11. Small-world anatomical networks in the human brain revealed by cortical thickness from MRI.

    Science.gov (United States)

    He, Yong; Chen, Zhang J; Evans, Alan C

    2007-10-01

    An important issue in neuroscience is the characterization for the underlying architectures of complex brain networks. However, little is known about the network of anatomical connections in the human brain. Here, we investigated large-scale anatomical connection patterns of the human cerebral cortex using cortical thickness measurements from magnetic resonance images. Two areas were considered anatomically connected if they showed statistically significant correlations in cortical thickness and we constructed the network of such connections using 124 brains from the International Consortium for Brain Mapping database. Significant short- and long-range connections were found in both intra- and interhemispheric regions, many of which were consistent with known neuroanatomical pathways measured by human diffusion imaging. More importantly, we showed that the human brain anatomical network had robust small-world properties with cohesive neighborhoods and short mean distances between regions that were insensitive to the selection of correlation thresholds. Additionally, we also found that this network and the probability of finding a connection between 2 regions for a given anatomical distance had both exponentially truncated power-law distributions. Our results demonstrated the basic organizational principles for the anatomical network in the human brain compatible with previous functional networks studies, which provides important implications of how functional brain states originate from their structural underpinnings. To our knowledge, this study provides the first report of small-world properties and degree distribution of anatomical networks in the human brain using cortical thickness measurements.

  12. Effects of cigarette smoking on cortical thickness in major depressive disorder.

    Science.gov (United States)

    Zorlu, Nabi; Cropley, Vanessa Louise; Zorlu, Pelin Kurtgoz; Delibas, Dursun Hakan; Adibelli, Zehra Hilal; Baskin, Emel Pasa; Esen, Özgür Sipahi; Bora, Emre; Pantelis, Christos

    2017-01-01

    Findings of surface-based morphometry studies in major depressive disorder (MDD) are still inconsistent. Given that cigarette smoking is highly prevalent in MDD and has documented negative effects on the brain, it is possible that some of the inconsistencies may be partly explained by cigarette use. The aim of the current study was to examine the influence of cigarette smoking on brain structure in MDD. 50 MDD patients (25 smokers and 25 non-smokers) and 22 age, education, gender and BMI matched non-smoker healthy controls underwent structural magnetic resonance imaging. Thickness and area of the cortex were measured using surface-based morphometry implemented with Freesurfer (v5.3.0). The non-smoker MDD patients had significantly increased cortical thickness, including in the left temporal cortex (p smoked compared to non-smoking patients in regions that overlapped with the regions found to be increased in non-smoking patients in comparison to controls. Non-smoker MDD patients had increased surface area in the right lateral occipital cortex (p = 0.009). We did not find any region where cortical thickness or surface area significantly differed between controls and either smoker MDD patients or all MDD patients. The findings of the current study suggest that cigarette smoking is associated with cortical thinning in regions found to be increased in patients with MDD. However, these results should be considered preliminary due to methodological limitations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Cortical Thickness in Fusiform Face Area Predicts Face and Object Recognition Performance.

    Science.gov (United States)

    McGugin, Rankin W; Van Gulick, Ana E; Gauthier, Isabel

    2016-02-01

    The fusiform face area (FFA) is defined by its selectivity for faces. Several studies have shown that the response of FFA to nonface objects can predict behavioral performance for these objects. However, one possible account is that experts pay more attention to objects in their domain of expertise, driving signals up. Here, we show an effect of expertise with nonface objects in FFA that cannot be explained by differential attention to objects of expertise. We explore the relationship between cortical thickness of FFA and face and object recognition using the Cambridge Face Memory Test and Vanderbilt Expertise Test, respectively. We measured cortical thickness in functionally defined regions in a group of men who evidenced functional expertise effects for cars in FFA. Performance with faces and objects together accounted for approximately 40% of the variance in cortical thickness of several FFA patches. Whereas participants with a thicker FFA cortex performed better with vehicles, those with a thinner FFA cortex performed better with faces and living objects. The results point to a domain-general role of FFA in object perception and reveal an interesting double dissociation that does not contrast faces and objects but rather living and nonliving objects.

  14. NPY neuron-specific Y2 receptors regulate adipose tissue and trabecular bone but not cortical bone homeostasis in mice.

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    Yan-Chuan Shi

    Full Text Available BACKGROUND: Y2 receptor signalling is known to be important in neuropeptide Y (NPY-mediated effects on energy homeostasis and bone physiology. Y2 receptors are located post-synaptically as well as acting as auto receptors on NPY-expressing neurons, and the different roles of these two populations of Y2 receptors in the regulation of energy homeostasis and body composition are unclear. METHODOLOGY/PRINCIPAL FINDINGS: We thus generated two conditional knockout mouse models, Y2(lox/lox and NPYCre/+;Y2(lox/lox, in which Y2 receptors can be selectively ablated either in the hypothalamus or specifically in hypothalamic NPY-producing neurons of adult mice. Specific deletion of hypothalamic Y2 receptors increases food intake and body weight compared to controls. Importantly, specific ablation of hypothalamic Y2 receptors on NPY-containing neurons results in a significantly greater adiposity in female but not male mice, accompanied by increased hepatic triglyceride levels, decreased expression of liver carnitine palmitoyltransferase (CPT1 and increased expression of muscle phosphorylated acetyl-CoA carboxylase (ACC. While food intake, body weight, femur length, bone mineral content, density and cortical bone volume and thickness are not significantly altered, trabecular bone volume and number were significantly increased by hypothalamic Y2 deletion on NPY-expressing neurons. Interestingly, in situ hybridisation reveals increased NPY and decreased proopiomelanocortin (POMC mRNA expression in the arcuate nucleus of mice with hypothalamus-specific deletion of Y2 receptors in NPY neurons, consistent with a negative feedback mechanism between NPY expression and Y2 receptors on NPY-ergic neurons. CONCLUSIONS/SIGNIFICANCE: Taken together these data demonstrate the anti-obesogenic role of Y2 receptors in the brain, notably on NPY-ergic neurons, possibly via inhibition of NPY neurons and concomitant stimulation of POMC-expressing neurons in the arcuate nucleus of

  15. In Vivo Assessment of Elasticity of Child Rib Cortical Bone Using Quantitative Computed Tomography

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    Y. Zhu

    2017-01-01

    Full Text Available Elasticity of the child rib cortical bone is poorly known due to the difficulties in obtaining specimens to perform conventional tests. It was shown on the femoral cortical bone that elasticity is strongly correlated with density for both children and adults through a unique relationship. Thus, it is assumed that the relationships between the elasticity and density of adult rib cortical bones could be expanded to include that of children. This study estimated in vivo the elasticity of the child rib cortical bone using quantitative computed tomography (QCT. Twenty-eight children (from 1 to 18 y.o. were considered. Calibrated QCT images were prescribed for various thoracic pathologies. The Hounsfield units were converted to bone mineral density (BMD. A relationship between the BMD and the elasticity of the rib cortical bone was applied to estimate the elasticity of children’s ribs in vivo. The estimated elasticity increases with growth (7.1 ± 2.5 GPa at 1 y.o. up to 11.6 ± 1.9 GPa at 18 y.o.. This data is in agreement with the few previous values obtained using direct measurements. This methodology paves the way for in vivo assessment of the elasticity of the child cortical bone based on calibrated QCT images.

  16. In vitro study of adhesive polymethylmethacrylate bone cement bonding to cortical bone in maxillofacial surgery.

    Science.gov (United States)

    Smeets, Ralf; Marx, Rudolf; Kolk, Andreas; Said-Yekta, Sareh; Grosjean, Maurice B; Stoll, Christian; Tinschert, Joachim; Wirtz, Dieter C; Riediger, Dieter; Endres, Kira

    2010-12-01

    In the treatment of midface fractures, the fragments are immobilized using screws and plates for osteosynthesis until reunion has occurred. This method involves drilling holes for the insertion of the screws, which can be associated with additional fracturing of the corresponding bone owing to the complex architecture and thin layers of facial bone. To alleviate this problem, new adhesive techniques for fixing the plates for osteosynthesis have been investigated, mitigating the detrimental effects of screw hole drilling. In the present experimental study, the strength of this adhesive bond and its resistance to hydrolysis were investigated. To determine the adhesive bonding strength, a tension test was implemented. Osteosynthesis plates with screw holes 1.3 mm in diameter were fixed to cortical bone samples of bovine femur using ultraviolet (UV) light-curing polymethylmethacrylate bone cement. To facilitate bonding, the surface of the bone was conditioned with an amphiphilic bonding agent before cementing. UV light curing was implemented using either a conventional UV unit, such as is used in dentistry, or with a specialized UV unit with a limited emission spectrum but high luminosity. Reference control samples were prepared without application of the bone bonding agent. After this procedure, the samples were stored for 1 to 7 days at 37°C submerged in 0.9% saline solution before being subjected to the tension test. Without the bone bonding agent, the bonding strength was 0.2 MPa. The primary average bonding strength at day 0 was 8.5 MPa when cured with the conventional UV unit and 14 MPa for the samples cured with the specialized UV unit. An almost constant average bond strength of 8 and 16 MPa was noted for all samples stored up to 7 days after curing with the conventional and specialized UV unit, respectively. With the development of a new bone bonding agent, a method is now available to promote the bonding between the hydrophilic bone surface and the

  17. Post-traumatic transient cortical blindness in a child with occipital bone fracture.

    Science.gov (United States)

    Ng, Rachel H C

    2016-12-01

    Cortical blindness as sequelae of trauma has been reported in literature but mostly in the setting of occipital cortex or visual tract damages. We present a case of transient cortical blindness in a child following a closed head injury with a non-displaced occipital bone fracture and underlying occipital lobe contusion. We discuss the pathophysiology behind Post-traumatic transient cortical blindness, relevant investigations, and current management.

  18. OPTICAL DENSITY OF CORTICAL BONE MATRIX IS DIMINISHED IN EXPERIMENTALLY INDUCED OSTEOPOROSIS

    Directory of Open Access Journals (Sweden)

    Jovan Janić

    2016-06-01

    Full Text Available Osteoporosis is characterized by low bone mineral density (BMD and abnormalities in bone structural and material properties, with unexplained low trauma fractures. The aim of the present study was to quantify the optical density of cortical bone matrix in rats with experimentally induced osteoporosis by ovariectomy. The experimental group was divided in two equal subgroups, the first sacrificed in the third month after ovariectomy and second sacrificed in the fifth month after ovariectomy. After decalcification, on routinely stained histopathologic sections optical density (OD, standard deviation of OD, mode OD, minimal and maximal OD of cortical bone matrix were estimated. Mean optical density and mode optical density of cortical bone were statistically higher in the control than in the experimental group (p<0.05. Maximal optical density of cortical bone was significantly lower in rats three months after ovariectomy than in other groups. Obtained results indicate that in experimentally induced osteoporosis the optical density of cortical bone matrix is diminished, similarly to low bone mineral density.

  19. Cortical thickness and inattention/hyperactivity symptoms in young children: a population-based study.

    Science.gov (United States)

    Mous, S E; Muetzel, R L; El Marroun, H; Polderman, T J C; van der Lugt, A; Jaddoe, V W; Hofman, A; Verhulst, F C; Tiemeier, H; Posthuma, D; White, T

    2014-11-01

    While many neuroimaging studies have investigated the neurobiological basis of attention deficit hyperactivity disorder (ADHD), few have studied the neurobiology of attention problems in the general population. The ability to pay attention falls along a continuum within the population, with children with ADHD at one extreme of the spectrum and, therefore, a dimensional perspective of evaluating attention problems has an added value to the existing literature. Our goal was to investigate the relationship between cortical thickness and inattention and hyperactivity symptoms in a large population of young children. This study is embedded within the Generation R Study and includes 6- to 8-year-old children (n = 444) with parent-reported attention and hyperactivity measures and high-resolution structural imaging data. We investigated the relationship between cortical thickness across the entire brain and the Child Behavior Checklist Attention Deficit Hyperactivity Problems score. We found that greater attention problems and hyperactivity were associated with a thinner right and left postcentral gyrus. When correcting for potential confounding factors and multiple testing, these associations remained significant. In a large, population-based sample we showed that young (6- to 8-year-old) children who show more attention problems and hyperactivity have a thinner cortex in the region of the right and left postcentral gyrus. The postcentral gyrus, being the primary somatosensory cortex, reaches its peak growth early in development. Therefore, the thinner cortex in this region may reflect either a deviation in cortical maturation or a failure to reach the same peak cortical thickness compared with children without attention or hyperactivity problems.

  20. Cortical and Trabecular Bone Microstructure Did Not Recover at Weight-Bearing Skeletal Sites and Progressively Deteriorated at Non-Weight-Bearing Sites During the Year Following International Space Station Missions.

    Science.gov (United States)

    Vico, Laurence; van Rietbergen, Bert; Vilayphiou, Nicolas; Linossier, Marie-Thérèse; Locrelle, Hervé; Normand, Myriam; Zouch, Mohamed; Gerbaix, Maude; Bonnet, Nicolas; Novikov, Valery; Thomas, Thierry; Vassilieva, Galina

    2017-06-02

    Risk for premature osteoporosis is a major health concern in astronauts and cosmonauts; the reversibility of the bone lost at the weight-bearing bone sites is not established, although it is suspected to take longer than the mission length. The bone three-dimensional structure and strength that could be uniquely affected by weightlessness is currently unknown. Our objective is to evaluate bone mass, microarchitecture, and strength of weight-bearing and non-weight-bearing bone in 13 cosmonauts before and for 12 months after a 4-month to 6-month sojourn in the International Space Station (ISS). Standard and advanced evaluations of trabecular and cortical parameters were performed using high-resolution peripheral quantitative computed tomography. In particular, cortical analyses involved determination of the largest common volume of each successive individual scan to improve the precision of cortical porosity and density measurements. Bone resorption and formation serum markers, and markers reflecting osteocyte activity or periosteal metabolism (sclerostin, periostin) were evaluated. At the tibia, in addition to decreased bone mineral densities at cortical and trabecular compartments, a 4% decrease in cortical thickness and a 15% increase in cortical porosity were observed at landing. Cortical size and density subsequently recovered and serum periostin changes were associated with cortical recovery during the year after landing. However, tibial cortical porosity or trabecular bone failed to recover, resulting in compromised strength. The radius, preserved at landing, unexpectedly developed postflight fragility, from 3 months post-landing onward, particularly in its cortical structure. Remodeling markers, uncoupled in favor of bone resorption at landing, returned to preflight values within 6 months, then declined farther to lower than preflight values. Our findings highlight the need for specific protective measures not only during, but also after spaceflight, because

  1. Fetal exposure to maternal depressive symptoms is associated with cortical thickness in late childhood.

    Science.gov (United States)

    Sandman, Curt A; Buss, Claudia; Head, Kevin; Davis, Elysia Poggi

    2015-02-15

    Maternal depression is one of the most common prenatal complications. The consequences of fetal exposure to maternal depression are poorly understood. The aim of this study is to examine the association between fetal exposure to maternal depressive symptoms and cortical thickness in children 6-9 years old. A prospective, longitudinal study of maternal depressive symptoms at 19, 25, and 31 weeks' gestation was followed by acquisition of a structural magnetic resonance imaging scan in 81 children (age, 86.1 ± 9.9 months). Significant (p < .01) cortical thinning in children primarily in the right frontal lobes was associated with exposure to prenatal maternal depression. The strongest association was at 25 weeks' gestation; exposure to maternal depression at 25 gestational weeks was associated with cortical thinning in 19% of the whole cortex and 24% of the frontal lobes, primarily in the right superior, medial orbital, and frontal pole regions of the prefrontal cortex (p < .01). The significant association between prenatal maternal depression and child externalizing behavior (p < .05) was mediated by cortical thinning in prefrontal areas of the right hemisphere. The pattern of cortical thinning in children exposed to prenatal maternal depression is similar to patterns in depressed patients and in individuals with risk for depression. Exposure to prenatal depression coupled with subsequent cortical thinning was associated with presence of externalizing behavior in preadolescent children and may be prodromal markers of risk for dysphoria. Vulnerability to prenatal influences at 25 gestational weeks may result from the enormous growth and dramatic structural changes in the nervous system. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  2. Breadth and age-dependency of relations between cortical thickness and cognition

    Science.gov (United States)

    Salthouse, Timothy A.; Habeck, Christian; Razlighi, Qolamreza; Barulli, Daniel; Gazes, Yunglin; Stern, Yaakov

    2015-01-01

    Recent advances in neuroimaging have identified a large number of neural measures that could be involved in age-related declines in cognitive functioning. A popular method of investigating neural-cognition relations has been to determine the brain regions in which a particular neural measure is associated with the level of specific cognitive measures. Although this procedure has been informative, it ignores the strong interrelations that typically exist among the measures in each modality. An alternative approach involves investigating the number and identity of distinct dimensions within the set of neural measures and within the set of cognitive measures prior to examining relations between the two types of measures. The procedure is illustrated with data from 297 adults between 20 and 79 years of age with cortical thickness in different brain regions as the neural measures, and performance on 12 cognitive tests as the cognitive measures. The results revealed that most of the relations between cortical thickness and cognition occurred at a general level corresponding to variance shared among different brain regions and among different cognitive measures. In addition, the strength of the thickness-cognition relation was substantially reduced after controlling the variation in age, which suggests that at least some of the thickness-cognition relations in age-heterogeneous samples may be attributable to the influence of age on each type of measure. PMID:26356042

  3. Bidirectional axial transmission can improve accuracy and precision of ultrasonic velocity measurement in cortical bone: a validation on test materials.

    Science.gov (United States)

    Bossy, Emmanuel; Talmant, Maryline; Defontaine, Marielle; Patat, Frédéric; Laugier, Pascal

    2004-01-01

    The axial transmission technique uses a linear arrangement of ultrasonic emitters and receivers placed on a same side of a cortical bone site in contact with the skin, involving ultrasonic propagation along the axis of bone. The velocity of the waves radiated from bone has been shown to reflect bone status. The thickness and composition of soft tissue may vary along the length of the bone, between different skeletal sites, or between subjects. Hence, accurate estimates of velocity require first to eliminate the effect of the overlying soft tissue that is traversed by the ultrasound wave. To correct for such bias without measuring soft tissue properties, we designed new ultrasonic probes in the 1-2 MHz frequency range. It is based on propagation along the bone surface in two opposite directions from two sources placed on both sides of a unique group of receivers. The aim is to obtain an unbiased estimate of the velocity without any intermediate calculation of soft tissue properties, such as thickness variation or velocity. Validation tests were performed on academic material such as Perspex or aluminum. We found that head wave velocity values could be biased by more than 10% for inclination of a few degrees between the test specimen surface and the probe. On test materials, the compensation procedure implemented in our probe led to a relative precision error on velocity measurement lower than 0.2 to 0.3%. These results suggest that the correction procedure allows measuring in vivo velocities independently of soft tissue properties.

  4. Differential tinnitus-related neuroplastic alterations of cortical thickness and surface area.

    Science.gov (United States)

    Meyer, Martin; Neff, Patrick; Liem, Franziskus; Kleinjung, Tobias; Weidt, Steffi; Langguth, Berthold; Schecklmann, Martin

    2016-12-01

    Structural neuroimaging techniques have been used to identify cortical and subcortical regions constituting the neuroarchitecture of tinnitus. One recent investigation used voxel-based morphometry (VBM) to analyze a sample of tinnitus patients (TI, n = 257) (Schecklmann et al., 2013). A negative relationship between individual distress and cortical volume (CV) in bilateral auditory regions was observed. However, CV has meanwhile been identified as a neuroanatomical measurement that confounds genetically distinct neuroanatomical traits, namely cortical thickness (CT) and cortical surface area (CSA). We performed a re-analysis of the identical sample using the automated FreeSurfer surface-based morphometry (SBM) approach (Fischl, 2012). First, we replicated the negative correlation between tinnitus distress and bilateral supratemporal gray matter volume. Second, we observed a negative correlation for CSA in the left periauditory cortex and anterior insula. Furthermore, we noted a positive correlation between tinnitus duration and CT in the left periauditory cortex as well as a negative correlation in the subcallosal anterior cingulate, a region collated to the serotonergic circuit and germane to inhibitory functions. In short, the results elucidate differential neuroanatomical alterations of CSA and CT for the two independent tinnitus-related psychological traits distress and duration. Beyond this, the study provides further evidence for the distinction and specific susceptibility of CSA and CT within the context of neuroplasticity of the human brain. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Dance Experience and Associations with Cortical Gray Matter Thickness in the Aging Population

    Directory of Open Access Journals (Sweden)

    Shai Porat

    2016-10-01

    Full Text Available Introduction: We investigated the effect dance experience may have on cortical gray matter thickness and cognitive performance in elderly participants with and without mild cognitive impairment (MCI. Methods: 39 cognitively normal and 48 MCI elderly participants completed a questionnaire regarding their lifetime experience with music, dance, and song. Participants identified themselves as either dancers or nondancers. All participants received structural 1.5-tesla MRI scans and detailed clinical and neuropsychological evaluations. An advanced 3D cortical mapping technique was then applied to calculate cortical thickness. Results: Despite having a trend-level significantly thinner cortex, dancers performed better in cognitive tasks involving learning and memory, such as the California Verbal Learning Test-II (CVLT-II short delay free recall (p = 0.004, the CVLT-II long delay free recall (p = 0.003, and the CVLT-II learning over trials 1-5 (p = 0.001. Discussion: Together, these results suggest that dance may result in an enhancement of cognitive reserve in aging, which may help avert or delay MCI.

  6. LOGISMOS-B for primates: primate cortical surface reconstruction and thickness measurement

    Science.gov (United States)

    Oguz, Ipek; Styner, Martin; Sanchez, Mar; Shi, Yundi; Sonka, Milan

    2015-03-01

    Cortical thickness and surface area are important morphological measures with implications for many psychiatric and neurological conditions. Automated segmentation and reconstruction of the cortical surface from 3D MRI scans is challenging due to the variable anatomy of the cortex and its highly complex geometry. While many methods exist for this task in the context of the human brain, these methods are typically not readily applicable to the primate brain. We propose an innovative approach based on our recently proposed human cortical reconstruction algorithm, LOGISMOS-B, and the Laplace-based thickness measurement method. Quantitative evaluation of our approach was performed based on a dataset of T1- and T2-weighted MRI scans from 12-month-old macaques where labeling by our anatomical experts was used as independent standard. In this dataset, LOGISMOS-B has an average signed surface error of 0.01 +/- 0.03mm and an unsigned surface error of 0.42 +/- 0.03mm over the whole brain. Excluding the rather problematic temporal pole region further improves unsigned surface distance to 0.34 +/- 0.03mm. This high level of accuracy reached by our algorithm even in this challenging developmental dataset illustrates its robustness and its potential for primate brain studies.

  7. Dance Experience and Associations with Cortical Gray Matter Thickness in the Aging Population.

    Science.gov (United States)

    Porat, Shai; Goukasian, Naira; Hwang, Kristy S; Zanto, Theodore; Do, Triet; Pierce, Jonathan; Joshi, Shantanu; Woo, Ellen; Apostolova, Liana G

    2016-01-01

    We investigated the effect dance experience may have on cortical gray matter thickness and cognitive performance in elderly participants with and without mild cognitive impairment (MCI). 39 cognitively normal and 48 MCI elderly participants completed a questionnaire regarding their lifetime experience with music, dance, and song. Participants identified themselves as either dancers or nondancers. All participants received structural 1.5-tesla MRI scans and detailed clinical and neuropsychological evaluations. An advanced 3D cortical mapping technique was then applied to calculate cortical thickness. Despite having a trend-level significantly thinner cortex, dancers performed better in cognitive tasks involving learning and memory, such as the California Verbal Learning Test-II (CVLT-II) short delay free recall (p = 0.004), the CVLT-II long delay free recall (p = 0.003), and the CVLT-II learning over trials 1-5 (p = 0.001). Together, these results suggest that dance may result in an enhancement of cognitive reserve in aging, which may help avert or delay MCI.

  8. Cognitive insight is associated with cortical thickness in first-episode psychosis.

    Science.gov (United States)

    Buchy, Lisa; Barbato, Mariapaola; MacMaster, Frank P; Bray, Signe; Clark, Darren; Deighton, Stephanie; Addington, Jean

    2016-04-01

    Compared to non-clinical subjects, people with psychosis show poor cognitive insight as reflected in low Self-Reflectiveness and high Self-Certainty. Neuroimaging studies have reported that 1) low Self-Reflectiveness is associated with volumetric reductions in ventrolateral prefrontal cortex (VLPFC), 2) higher Self-Certainty is associated with volumetric reductions in hippocampus, and 3) higher Self-Certainty is associated with fractional anisotropy in the fornix, in people with psychosis. The aims of the current study were to expand on this research by 1) performing an exploratory whole-brain cortical thickness analysis of the neural correlates of cognitive insight, to reveal whether regions outside the VLPFC are important for cognitive insight, and 2) to evaluate associations between cognitive insight and subfields of the hippocampus, which are distinct, interacting, and have different functions. We also aimed to replicate previous research documenting associations between cognitive insight and 3) total hippocampal volumes and 4) fornix fractional anisotropy. Fifteen people with a first-episode psychosis completed the Beck Cognitive Insight Scale and provided magnetic resonance and diffusion tensor imaging scans. Cortical thickness and hippocampal volumes were analyzed in FreeSurfer, and fornixfractional anisotropy was analyzed in Diffusion Toolkit/TrackVis. Higher Self-Reflectiveness and lower Self-Certainty significantly associated with thickness and thinness in VLPFC, respectively, as well as thickness and thinness in widespread frontal, parietal and temporal cortices. No associations emerged between Self-Reflectiveness or Self-Certainty and hippocampal total or sub-field volumes, or fornix fractional anisotropy. Results suggest that the neural correlates of cognitive insight involve a network of frontal, temporal and parietal brain regions.

  9. Brain volumetrics, regional cortical thickness and radiographic findings in children with cyanotic congenital heart disease using quantitative magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Alsiagy A. Salama, M.D.

    2016-12-01

    Conclusions: Children with CCHD show MRI evidence of micro- and macro vascular injury, reduced brain volume and cortical thickness. Brain volume loss correlated with hsCRP, oxygen saturation and packed cell volume.

  10. Assessing temperature changes in cortical bone using variable flip-angle ultrashort echo-time MRI

    Science.gov (United States)

    Han, Misung; Scott, Serena J.; Ozhinsky, Eugene; Salgaonakar, Vasant A.; Jones, Peter D.; Larson, Peder E. Z.; Diederich, Chris J.; Rieke, Viola; Krug, Roland

    2017-03-01

    MR-guided high-intensity focused ultrasound ablation is a promising, noninvasive method for treatment of bone tumors and palliation of pain. During thermal therapy, temperature mapping is necessary to ensure proper heat deposition in targeted tumors as well as to prevent unnecessary heating in surrounding tissues. Conventional MR thermometry exploits the proton resonant frequency shift of water protons, which normally requires a long echo time; therefore, this method is not appropriate for cortical bone due to its short T2* relaxation time. This work demonstrates that ultrashort echo-time MRI can characterize T1 changes in cortical bone caused by temperature changes. Ex vivo experiments were performed to heat diaphysis segments of bovine femurs with an interstitial ultrasound applicator. The T1 increase in the heated parts of cortical bone was observed. The temerature dependence of T1 in cortical born was also assessed by heating bovine bone samples in a temperature-controlled water bath. T1 mapping of cortical bone enabled by ultrashort echo-time MRI might allow for more accurate characterization of thermal dose during treatment of bone tumors.

  11. Ovariectomy-induced changes in aged beagles : histomorphometry of rib cortical bone.

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, A. K.; Bhattacharyya, M. H.; Miller, S.; Sacco-Gibson, N.; Center for Mechanistic Biology and Biotechnology; Univ. of Utah; Procter & Gamble Pharmaceuticals

    1998-03-01

    Bone loss associated with estrogen depletion is well documented in cancellous bone but less well characterized in cortical bone. The effects of ovariectomy on the aged beagle skeleton were studied by histomorphometric analysis of the cortical bone in sequential rib biopsies. Biopsies were taken from each ovariectomized or sham-operated dog at the time of surgery and at 1, 4, and 8.5 months after surgery. Just prior to each postoperative biopsy, tetracycline, calcein, and xylenol orange, respectively, were administered by a fluorochrome labeling procedure (2d-10d-2d) to provide markers of bone formation. Analysis of sequential rib biopsies provided a means to follow the ovariectomy response over time and to compare each animal against its own baseline. Though ovariectomy did not influence histomorphometric indices at 1 month after surgery, a transient increase in cortical bone formation occurred thereafter, with a sixfold increase over that of sham-operated dogs at 4 months (P < 0.001) and a return to near control levels at 8.5 months. Cortical porosity increased by the fourth month after ovariectomy and remained high at 8.5 months. These data demonstrate for the first time that rib cortical bone is a responsive site for the effects of ovariectomy in aged female dogs.

  12. Increased intra-cortical porosity reduces bone stiffness and strength in pediatric patients with osteogenesis imperfecta.

    Science.gov (United States)

    Vardakastani, V; Saletti, D; Skalli, W; Marry, P; Allain, J M; Adam, C

    2014-12-01

    Osteogenesis imperfecta (OI) is a heritable disease occurring in one out of every 20,000 births. Although it is known that Type I collagen mutation in OI leads to increased bone fragility, the mechanism of this increased susceptibility to fracture is not clear. The aim of this study was to assess the microstructure of cortical bone fragments from patients with osteogenesis imperfecta (OI) using polarized light microscopy, and to correlate microstructural observations with the results of previously performed mechanical compression tests on bone from the same source. Specimens of cortical bone were harvested from the lower limbs of three (3) OI patients at the time of surgery, and were divided into two groups. Group 1 had been subjected to previous micro-mechanical compression testing, while Group 2 had not been subjected to any prior testing. Polarized light microscopy revealed disorganized bone collagen architecture as has been previously observed, as well as a large increase in the areal porosity of the bone compared to typical values for healthy cortical bone, with large (several hundred micron sized), asymmetrical pores. Importantly, the areal porosity of the OI bone samples in Group 1 appears to correlate strongly with their previously measured apparent Young's modulus and compressive strength. Taken together with prior nanoindentation studies on OI bone tissue, the results of this study suggest that increased intra-cortical porosity is responsible for the reduction in macroscopic mechanical properties of OI cortical bone, and therefore that in vivo imaging modalities with resolutions of ~100 μm or less could potentially be used to non-invasively assess bone strength in OI patients. Although the number of subjects in this study is small, these results highlight the importance of further studies in OI bone by groups with access to human OI tissue in order to clarify the relationship between increased porosity and reduced macroscopic mechanical integrity.

  13. Midline lumbar fusion using cortical bone trajectory screws. Preliminary report

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    Mateusz Bielecki

    2016-09-01

    Full Text Available Introduction : Midline lumbar fusion (MIDLF using cortical bone trajectory is an alternative method of transpedicular spinal fusion for degenerative disease. The new entry points’ location and screwdriving direction allow the approach-related morbidity to be reduced. Aim: To present our preliminary experience with the MIDLF technique on the first 5 patients with lumbar degenerative disease and with follow-up of at least 6 months. Material and methods: Retrospective analysis was performed on the first 5 patients with foraminal (4 or central (1 stenosis operated on between December 2014 and February 2015. Three patients were fused at L4–L5 and two at the L5–S1 level. Results: No intra- or post-operative complications occurred with this approach. An improvement regarding the leading symptom in the early postoperative period (sciatica 4/4, claudication 1/1 was achieved in all patients. The mean improvements in the visual analogue scale for low back and leg pain were 2.2 and 4.8 respectively. The mean Oswestry Disability Index scores were 52% (range: 16–82% before surgery and 33% (range: 12–56% at 3-month follow-up (mean improvement 19%. At the most recent follow-up, 4 patients reported the maintenance of the satisfactory result. The early standing and follow-up X-rays showed satisfactory screw placement in all patients. Conclusions : In our initial experience, the MIDLF technique seems to be an encouraging alternative to traditional transpedicular trajectory screws when short level lumbar fusion is needed. Nevertheless, longer observations on larger groups of patients are needed to reliably evaluate the safety of the method and the sustainability of the results.

  14. Cortical bone development under the growth plate is regulated by mechanical load transfer.

    NARCIS (Netherlands)

    Tanck, E.J.M.; Hannink, G.J.; Ruimerman, R.; Buma, P.; Burger, E.H.; Huiskes, R.

    2006-01-01

    Longitudinal growth of long bones takes place at the growth plates. The growth plate produces new bone trabeculae, which are later resorbed or merged into the cortical shell. This process implies transition of trabecular metaphyseal sections into diaphyseal sections. We hypothesize that the developm

  15. Effect of micromorphology of cortical bone tissue on crack propagation under dynamic loading

    Science.gov (United States)

    Wang, Mayao; Gao, Xing; Abdel-Wahab, Adel; Li, Simin; Zimmermann, Elizabeth A.; Riedel, Christoph; Busse, Björn; Silberschmidt, Vadim V.

    2015-09-01

    Structural integrity of bone tissue plays an important role in daily activities of humans. However, traumatic incidents such as sports injuries, collisions and falls can cause bone fracture, servere pain and mobility loss. In addition, ageing and degenerative bone diseases such as osteoporosis can increase the risk of fracture [1]. As a composite-like material, a cortical bone tissue is capable of tolerating moderate fracture/cracks without complete failure. The key to this is its heterogeneously distributed microstructural constituents providing both intrinsic and extrinsic toughening mechanisms. At micro-scale level, cortical bone can be considered as a four-phase composite material consisting of osteons, Haversian canals, cement lines and interstitial matrix. These microstructural constituents can directly affect local distributions of stresses and strains, and, hence, crack initiation and propagation. Therefore, understanding the effect of micromorphology of cortical bone on crack initiation and propagation, especially under dynamic loading regimes is of great importance for fracture risk evaluation. In this study, random microstructures of a cortical bone tissue were modelled with finite elements for four groups: healthy (control), young age, osteoporosis and bisphosphonate-treated, based on osteonal morphometric parameters measured from microscopic images for these groups. The developed models were loaded under the same dynamic loading conditions, representing a direct impact incident, resulting in progressive crack propagation. An extended finite-element method (X-FEM) was implemented to realize solution-dependent crack propagation within the microstructured cortical bone tissues. The obtained simulation results demonstrate significant differences due to micromorphology of cortical bone, in terms of crack propagation characteristics for different groups, with the young group showing highest fracture resistance and the senior group the lowest.

  16. Effect of micromorphology of cortical bone tissue on crack propagation under dynamic loading

    Directory of Open Access Journals (Sweden)

    Wang Mayao

    2015-01-01

    Full Text Available Structural integrity of bone tissue plays an important role in daily activities of humans. However, traumatic incidents such as sports injuries, collisions and falls can cause bone fracture, servere pain and mobility loss. In addition, ageing and degenerative bone diseases such as osteoporosis can increase the risk of fracture [1]. As a composite-like material, a cortical bone tissue is capable of tolerating moderate fracture/cracks without complete failure. The key to this is its heterogeneously distributed microstructural constituents providing both intrinsic and extrinsic toughening mechanisms. At micro-scale level, cortical bone can be considered as a four-phase composite material consisting of osteons, Haversian canals, cement lines and interstitial matrix. These microstructural constituents can directly affect local distributions of stresses and strains, and, hence, crack initiation and propagation. Therefore, understanding the effect of micromorphology of cortical bone on crack initiation and propagation, especially under dynamic loading regimes is of great importance for fracture risk evaluation. In this study, random microstructures of a cortical bone tissue were modelled with finite elements for four groups: healthy (control, young age, osteoporosis and bisphosphonate-treated, based on osteonal morphometric parameters measured from microscopic images for these groups. The developed models were loaded under the same dynamic loading conditions, representing a direct impact incident, resulting in progressive crack propagation. An extended finite-element method (X-FEM was implemented to realize solution-dependent crack propagation within the microstructured cortical bone tissues. The obtained simulation results demonstrate significant differences due to micromorphology of cortical bone, in terms of crack propagation characteristics for different groups, with the young group showing highest fracture resistance and the senior group the

  17. The importance of murine cortical bone microstructure for microcrack initiation and propagation.

    Science.gov (United States)

    Voide, R; Schneider, P; Stauber, M; van Lenthe, G H; Stampanoni, M; Müller, R

    2011-12-01

    In order to better understand bone postyield behavior and consequently bone failure behavior, this study aimed first to investigate cortical bone microstructure and second, to relate cortical bone microstructure to microdamage initiation and propagation in C57BL/6 (B6) and C3H/He (C3H) mice; two murine inbred strains known for their differences in bone phenotype. Murine femora of B6 and C3H were loaded axially under compression in a stepwise manner. For each loading step, 3D data sets at a nominal resolution of 700 nm were acquired by means of synchrotron radiation-based computed tomography. Cortical bone microstructure was divided into three phases: the canal network, the osteocyte lacunar system, and microdamage. Canal volume density and canal unit volume both correlated highly to crack number density (canal volume density: R(2)=0.64, pcanal unit volume: R(2)=0.75, pcanal units in C3H bone were responsible for more microdamage accumulation compared to B6 bones. This more pronounced microdamage accumulation due to large intracortical bone voids, which eventually leads to a fatal macrocrack (fracture), represents a potential contributing factor to the higher incidence of bone fractures in the elderly. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Temperature Values Variability in Piezoelectric Implant Site Preparation: Differences between Cortical and Corticocancellous Bovine Bone

    Directory of Open Access Journals (Sweden)

    Luca Lamazza

    2016-01-01

    Full Text Available Purpose. Various parameters can influence temperature rise and detection during implant site preparation. The aim of this study is to investigate local temperature values in cortical and corticocancellous bovine bone during early stages of piezoelectric implant site preparation. Materials and Methods. 20 osteotomies were performed using a diamond tip (IM1s, Mectron Medical Technology, Carasco, Italy on two different types of bovine bone samples, cortical and corticocancellous, respectively. A standardized protocol was designed to provide constant working conditions. Temperatures were measured in real time at a fixed position by a fiber optic thermometer. Results. Significantly higher drilling time (154.90 sec versus 99.00 sec; p<0.0001 and temperatures (39.26°C versus 34.73°C; p=0.043 were observed in the cortical group compared to the corticocancellous group. A remarkable variability of results characterized the corticocancellous blocks as compared to the blocks of pure cortical bone. Conclusion. Bone samples can influence heat generation during in vitro implant site preparation. When compared to cortical bone, corticocancellous samples present more variability in temperature values. Even controlling most experimental factors, the impact of bone samples still remains one of the main causes of temperature variability.

  19. It is unclear if adjusting cortical thickness for changes in gray/white matter intensity ratio improves discrimination between normal aging, MCI, and AD.

    Science.gov (United States)

    Bauer, Corinna M; Cabral, Howard J; Killiany, Ronald J

    2014-03-01

    The contrast between gray and white matter in MRI is critical for accurately measuring cortical thickness. The gray/white matter intensity ratio (GWIR) has been proposed to be an important adjustment factor for cortical thickness measures in Alzheimer's disease (AD) and mild cognitive impairment (MCI). This study examined the GWIR and its influence on cortical thickness in normal aging, mild cognitive impairment (MCI), and AD. The ability for GWIR to discriminate between these groups was assessed on its own and as an adjustment factor for cortical thickness. Minimal age- and AD-related changes in GWIR were observed. GWIR was not able to differentiate between normal aging, MCI, and AD. However, adjusting cortical thickness for GWIR slightly improved the ability to discriminate between groups and the effect size of cortical thickness increased after adjusting for GWIR. This work demonstrates the ambiguity in adjusting cortical thickness measures for GWIR, particularly when attempting to discriminate between normal aging, MCI, and AD groups.

  20. Influence of bone microstructure on the mechanical properties of skull cortical bone - A combined experimental and computational approach.

    Science.gov (United States)

    Boruah, Sourabh; Subit, Damien L; Paskoff, Glenn R; Shender, Barry S; Crandall, Jeff R; Salzar, Robert S

    2017-01-01

    The strength and compliance of the dense cortical layers of the human skull have been examined since the beginning of the 20th century with the wide range in the observed mechanical properties attributed to natural biological variance. Since this variance may be explained by the difference in structural arrangement of bone tissue, micro-computed tomography (µCT) was used in conjunction with mechanical testing to study the relationship between the microstructure of human skull cortical coupons and their mechanical response. Ninety-seven bone samples were machined from the cortical tables of the calvaria of ten fresh post mortem human surrogates and tested in dynamic tension until failure. A linear response between stress and strain was observed until close to failure, which occurred at 0.6% strain on average. The effective modulus of elasticity for the coupons was 12.01 ± 3.28GPa. Porosity of the test specimens, determined from µCT, could explain only 51% of the variation of their effective elastic modulus. Finite element (FE) models of the tested specimens built from µCT images indicated that modeling the microstructural arrangement of the bone, in addition to the porosity, led to a marginal improvement of the coefficient of determination to 54%. Modulus for skull cortical bone for an element size of 50µm was estimated to be 19GPa at an average. Unlike the load bearing bones of the body, almost half of the variance in the mechanical properties of cortical bone from the skull may be attributed to differences at the sub-osteon (< 50µm) level. ANOVA tests indicated that effective failure stress and strain varied significantly between the frontal and parietal bones, while the bone phase modulus was different for the superior and inferior aspects of the calvarium. The micro FE models did not indicate any anisotropy attributable to the pores observable under µCT.

  1. Drilling in cortical bone: a finite element model and experimental investigations.

    Science.gov (United States)

    Lughmani, Waqas A; Bouazza-Marouf, Kaddour; Ashcroft, Ian

    2015-02-01

    Bone drilling is an essential part of many orthopaedic surgery procedures, including those for internal fixation and for attaching prosthetics. Estimation and control of bone drilling forces are critical to prevent drill-bit breakthrough, excessive heat generation, and mechanical damage to the bone. An experimental and computational study of drilling in cortical bone has been conducted. A 3D finite element (FE) model for prediction of thrust forces experienced during bone drilling has been developed. The model incorporates the dynamic characteristics involved in the process along with geometrical considerations. An elastic-plastic material model is used to predict the behaviour of cortical bone during drilling. The average critical thrust forces and torques obtained using FE analysis are found to be in good agreement with the experimental results.

  2. Specifications for machining the bovine cortical bone in relation to its microstructure.

    Science.gov (United States)

    Sugita, Naohiko; Mitsuishi, Mamoru

    2009-12-11

    Until date, many devices have been developed for cutting human bones during orthopedic surgeries. However, bones are anisotropic material, and their machining characteristics depend on the tool feed direction. In this study, microcutting of the bovine cortical bone is performed and its structure observed under a microscope. Furthermore, the formation of cutting chips and measurement of the cutting force during bone machining are dynamically observed while considering the anisotropy of bone tissue. In particular, the fracture of secondary osteons and crack propagation in bones are observed and analyzed. The results indicate that when the cut depth exceeds 20mum and is greater than the interval of concentric lamellae, cracks are formed together with chips. A new method for bone machining is proposed. This method is based on the characteristics of crack propagation in bones and is expected to produce low mechanical stress and realize highly efficient and precise machining of living tissues such as bones.

  3. Preliminary estimates of the calcium/phosphorus ratio at different cortical bone sites using synchrotron microCT

    Science.gov (United States)

    Tzaphlidou, M.; Speller, R.; Royle, G.; Griffiths, J.

    2006-04-01

    The Ca/P ratio was measured in cortical bone samples from the femoral neck, front and rear tibia of female rats (1.5 years of age), using synchrotron radiation microtomography. The use of a monoenergetic x-ray beam, as provided by the synchrotron facility, generates accurate 3D maps of the linear attenuation coefficient within the sample and hence gives the ability to map different chemical components. Data sets were taken at 20 keV for each bone sample and calibration phantoms. From the 3D data sets, multiple 2D slices were reconstructed with a slice thickness of ~28 µm and converted to Ca/P ratios using the calibration phantom results. Mean values (M ± SD) for cortical femoral, front and rear tibias are 2.12 ± 0.08, 1.75 ± 0.06 and 1.94 ± 0.07 respectively. These values were compared with those derived from different animals. Differences between the same bone sites from different animals are not significant (0.1 life style and bone use.

  4. Brain cortical thickness and surface area correlates of neurocognitive performance in patients with schizophrenia, bipolar disorder, and healthy adults.

    Science.gov (United States)

    Hartberg, C B; Sundet, K; Rimol, L M; Haukvik, U K; Lange, E H; Nesvåg, R; Dale, A M; Melle, I; Andreassen, O A; Agartz, I

    2011-11-01

    Relationships between cortical brain structure and neurocognitive functioning have been reported in schizophrenia, but findings are inconclusive, and only a few studies in bipolar disorder have addressed this issue. This is the first study to directly compare relationships between cortical thickness and surface area with neurocognitive functioning in patients with schizophrenia (n = 117) and bipolar disorder (n = 121) and healthy controls (n = 192). MRI scans were obtained, and regional cortical thickness and surface area measurements were analyzed for relationships with test scores from 6 neurocognitive domains. In the combined sample, cortical thickness in the right rostral anterior cingulate was inversely related to working memory, and cortical surface area in four frontal and temporal regions were positively related to neurocognitive functioning. A positive relationship between left transverse temporal thickness and processing speed was specific to schizophrenia. A negative relationship between right temporal pole thickness and working memory was specific to bipolar disorder. In conclusion, significant cortical structure/function relationships were found in a large sample of healthy controls and patients with schizophrenia or bipolar disorder. The differences that were found between schizophrenia and bipolar may indicate differential relationship patterns in the two disorders, which may be of relevance for understanding the underlying pathophysiology.

  5. Reproducibility of brain-cognition relationships using three cortical surface-based protocols: An exhaustive analysis based on cortical thickness.

    Science.gov (United States)

    Martínez, Kenia; Madsen, Sarah K; Joshi, Anand A; Joshi, Shantanu H; Román, Francisco J; Villalon-Reina, Julio; Burgaleta, Miguel; Karama, Sherif; Janssen, Joost; Marinetto, Eugenio; Desco, Manuel; Thompson, Paul M; Colom, Roberto

    2015-08-01

    People differ in their cognitive functioning. This variability has been exhaustively examined at the behavioral, neural and genetic level to uncover the mechanisms by which some individuals are more cognitively efficient than others. Studies investigating the neural underpinnings of interindividual differences in cognition aim to establish a reliable nexus between functional/structural properties of a given brain network and higher order cognitive performance. However, these studies have produced inconsistent results, which might be partly attributed to methodological variations. In the current study, 82 healthy young participants underwent MRI scanning and completed a comprehensive cognitive battery including measurements of fluid, crystallized, and spatial intelligence, along with working memory capacity/executive updating, controlled attention, and processing speed. The cognitive scores were obtained by confirmatory factor analyses. T1 -weighted images were processed using three different surface-based morphometry (SBM) pipelines, varying in their degree of user intervention, for obtaining measures of cortical thickness (CT) across the brain surface. Distribution and variability of CT and CT-cognition relationships were systematically compared across pipelines and between two cognitively/demographically matched samples to overcome potential sources of variability affecting the reproducibility of findings. We demonstrated that estimation of CT was not consistent across methods. In addition, among SBM methods, there was considerable variation in the spatial pattern of CT-cognition relationships. Finally, within each SBM method, results did not replicate in matched subsamples.

  6. Cortical Thickness, Surface Area and Subcortical Volume Differentially Contribute to Cognitive Heterogeneity in Parkinson's Disease.

    Directory of Open Access Journals (Sweden)

    Niels J H M Gerrits

    Full Text Available Parkinson's disease (PD is often associated with cognitive deficits, although their severity varies considerably between patients. Recently, we used voxel-based morphometry (VBM to show that individual differences in gray matter (GM volume relate to cognitive heterogeneity in PD. VBM does, however, not differentiate between cortical thickness (CTh and surface area (SA, which might be independently affected in PD. We therefore re-analyzed our cohort using the surface-based method FreeSurfer, and investigated (i CTh, SA, and (subcortical GM volume differences between 93 PD patients and 45 matched controls, and (ii the relation between these structural measures and cognitive performance on six neuropsychological tasks within the PD group. We found cortical thinning in PD patients in the left pericalcarine gyrus, extending to cuneus, precuneus and lingual areas and left inferior parietal cortex, bilateral rostral middle frontal cortex, and right cuneus, and increased cortical surface area in the left pars triangularis. Within the PD group, we found negative correlations between (i CTh of occipital areas and performance on a verbal memory task, (ii SA and volume of the frontal cortex and visuospatial memory performance, and, (iii volume of the right thalamus and scores on two verbal fluency tasks. Our primary findings illustrate that i CTh and SA are differentially affected in PD, and ii VBM and FreeSurfer yield non-overlapping results in an identical dataset. We argue that this discrepancy is due to technical differences and the subtlety of the PD-related structural changes.

  7. Calcifying tendinitis of the rotator cuff with cortical bone erosion.

    Science.gov (United States)

    Chan, Roxanne; Kim, David H; Millett, Peter J; Weissman, Barbara N

    2004-10-01

    Calcifying tendinitis occurs most commonly in the rotator cuff tendons, particularly involving the supraspinatus tendon insertion, and is often asymptomatic. Cortical erosion secondary to calcifying tendinitis has been reported in multiple locations, including in the rotator cuff tendons. We present a pathologically proven case of symptomatic calcifying tendinitis involving the infraspinatus tendon with cortical erosion with correlative radiographic, CT, and MR findings. The importance of considering this diagnosis when evaluating lytic lesions of the humerus and the imaging differential diagnosis of calcifying tendinitis and cortical erosion are discussed.

  8. Calcifying tendinitis of the rotator cuff with cortical bone erosion

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Roxanne; Kim, David H.; Millett, Peter J. [Harvard Medical School, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Weissman, Barbara N. [Harvard Medical School, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Brigham and Women' s Hospital, Department of Radiology, Musculoskeletal Division, Boston (United States)

    2004-10-01

    Calcifying tendinitis occurs most commonly in the rotator cuff tendons, particularly involving the supraspinatus tendon insertion, and is often asymptomatic. Cortical erosion secondary to calcifying tendinitis has been reported in multiple locations, including in the rotator cuff tendons. We present a pathologically proven case of symptomatic calcifying tendinitis involving the infraspinatus tendon with cortical erosion with correlative radiographic, CT, and MR findings. The importance of considering this diagnosis when evaluating lytic lesions of the humerus and the imaging differential diagnosis of calcifying tendinitis and cortical erosion are discussed. (orig.)

  9. Cortical and trabecular bone at the radius and tibia in male and female adolescents with Down syndrome: a peripheral quantitative computed tomography (pQCT) study.

    Science.gov (United States)

    González-Agüero, A; Vicente-Rodríguez, G; Gómez-Cabello, A; Casajús, J A

    2013-03-01

    We aimed to describe the structure and strength of the tibia and radius of adolescents with Down syndrome. We observed that despite higher levels of volumetric bone mineral density in determined skeletal sites, they are at higher risk of developing osteoporotic fractures in the future due to their lower bone strength indexes. The aims of the study were to describe the cortical and trabecular volumetric bone mineral density (vBMD), bone mineral content (BMC), area, and bone strength in adolescents with Down syndrome (DS) and to compare them with adolescents without disabilities. Thirty adolescents (11 girls) with DS and 28 without disabilities (10 girls) participated in the study. Peripheral quantitative computed tomography measurements were taken at proximal and distal sites of the tibia and radius. Values of total, trabecular, and cortical BMC; vBMD; and area were obtained of each scan. Cortical thickness and endosteal and periosteal circumferences were also measured, and different bone strength indexes were calculated. Student's t tests were applied between groups. The DS group showed greater vBMD at distal radius, BMC at proximal radius, and total and cortical vBMD at proximal tibia. The non-DS group showed higher total and trabecular area at the distal radius and total, cortical, and trabecular BMC and area at distal tibia. Higher values of periosteal and endosteal circumference and bone strength were also found in non-DS group. From these results, it can be believed that even with higher vBMD in determined skeletal sites, adolescents with DS are at higher risk of suffering bone fractures due to an increased fragility by lower resistance to load bending or torsion.

  10. Mechanistic fracture criteria for the failure of human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Nalla, Ravi K.; Kinney, John H.; Ritchie, Robert O.

    2002-12-13

    A mechanistic understanding of fracture in human bone is critical to predicting fracture risk associated with age and disease. Despite extensive work, a mechanistic framework for describing how the underlying microstructure affects the failure mode in bone is lacking.

  11. Value of renal cortical thickness as a predictor of renal function impairment in chronic renal disease patients

    Directory of Open Access Journals (Sweden)

    Samia Rafael Yamashita

    2015-02-01

    Full Text Available Objective: To determine the presence of linear relationship between renal cortical thickness, bipolar length, and parenchymal thickness in chronic kidney disease patients presenting with different estimated glomerular filtration rates (GFRs and to assess the reproducibility of these measurements using ultrasonography. Materials and Methods: Ultrasonography was performed in 54 chronic renal failure patients. The scans were performed by two independent and blinded radiologists. The estimated GFR was calculated using the Cockcroft-Gault equation. Interobserver agreement was calculated and a linear correlation coefficient (r was determined in order to establish the relationship between the different renal measurements and estimated GFR. Results: The correlation between GFR and measurements of renal cortical thickness, bipolar length, and parenchymal thickness was, respectively, moderate (r = 0.478; p < 0.001, poor (r = 0.380; p = 0.004, and poor (r = 0.277; p = 0.116. The interobserver agreement was considered excellent (0.754 for measurements of cortical thickness and bipolar length (0.833, and satisfactory for parenchymal thickness (0.523. Conclusion: The interobserver reproducibility for renal measurements obtained was good. A moderate correlation was observed between estimated GFR and cortical thickness, but bipolar length and parenchymal thickness were poorly correlated.

  12. Neuroanatomical correlates of tinnitus revealed by cortical thickness analysis and diffusion tensor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Aldhafeeri, Faten M. [The University of Liverpool, Department of Medical Imaging, School of Health Sciences, Liverpool (United Kingdom); King Khalid General Hospital, Ministry of Health, Radiology Department, Hafral-batin (Saudi Arabia); Mackenzie, Ian; Kay, Tony [Aintree University Hospitals NHS Foundation Trust, Liverpool (United Kingdom); Alghamdi, Jamaan [The University of Liverpool, Department of Medical Imaging, School of Health Sciences, Liverpool (United Kingdom); King Abdul Aziz University, Physics Department, Faculty of Sciences, Jeddah (Saudi Arabia); Sluming, Vanessa [The University of Liverpool, Department of Medical Imaging, School of Health Sciences, Liverpool (United Kingdom); Magnetic Resonance and Image Analysis Research Centre, Liverpool (United Kingdom)

    2012-08-15

    Tinnitus is a poorly understood auditory perception of sound in the absence of external stimuli. Convergent evidence proposes that tinnitus perception involves brain structural alterations as part of its pathophysiology. The aim of this study is to investigate the structural brain changes that might be associated with tinnitus-related stress and negative emotions. Using high-resolution magnetic resonance imaging and diffusion tensor imaging, we investigated grey matter and white matter (WM) alterations by estimating cortical thickness measures, fractional anisotropy and mean diffusivity in 14 tinnitus subjects and 14 age- and sex-matched non-tinnitus subjects. Significant cortical thickness reductions were found in the prefrontal cortex (PFC), temporal lobe and limbic system in tinnitus subjects compared to non-tinnitus subjects. Tinnitus sufferers were found to have disrupted WM integrity in tracts involving connectivity of the PFC, temporal lobe, thalamus and limbic system. Our results suggest that such neural changes may represent neural origins for tinnitus or consequences of tinnitus and its associations. (orig.)

  13. A histological investigation on tissue responses to titanium implants in cortical bone of the rat femur.

    Science.gov (United States)

    Ohtsu, A; Kusakari, H; Maeda, T; Takano, Y

    1997-03-01

    Implant materials are placed under various sites-including cortical bone, spongy bone, and bone marrow-at the same time according to the depth at implantation. Although cortical bone is an important site for the prognosis of implantation, detailed reports on tissue responses to implantation have been meager. The present study aims to reveal tissue responses to pure titanium implantation in rat femoris cortical bone. The rats received titanium bars surgically in their femurs and were sacrificed 1 day to 40 weeks post-implantation. The prepared tissue specimens were processed for light and transmission electron microscopy (TEM). Further histochemical detections were performed. One day post-implantation, empty osteocytic lacunae indicating degeneration of osteocytes were found in pre-existing cortical bone around the implant. Such pre-existing bone was replaced by new bone, but remained in part even 40 weeks post-implantation. Light microscopy showed that direct contact between the implant and new bone was identified 12 weeks post-implantation. Chronological and ultrastructural observation showed that new bone deposition appeared to proceed toward the implant, and that the intervening layer at the interface was derived from the degenerated debris of multinucleated giant cells and/or osteoblasts. Furthermore, it seemed that the width of intervening layer varied in relation to the distance from the blood vessels. The cells showing tartrate resistant acid phosphatase activity possessed cytological features of osteoclasts under TEM; they were frequently observed in perivascular sites near the implants even after osseointegration, suggesting that bone remodeling took place steadily around the implant.

  14. Sex-related differences of cortical thickness in patients with chronic abdominal pain.

    Directory of Open Access Journals (Sweden)

    Zhiguo Jiang

    Full Text Available Regional reductions in gray matter (GM have been reported in several chronic somatic and visceral pain conditions, including irritable bowel syndrome (IBS and chronic pancreatitis. Reported GM reductions include insular and anterior cingulate cortices, even though subregions are generally not specified. The majority of published studies suffer from limited sample size, heterogeneity of populations, and lack of analyses for sex differences. We aimed to characterize regional changes in cortical thickness (CT in a large number of well phenotyped IBS patients, taking into account the role of sex related differences.Cortical GM thickness was determined in 266 subjects (90 IBS [70 predominantly premenopausal female] and 176 healthy controls (HC [155 predominantly premenopausal female] using the Laboratory of Neuro Imaging (LONI Pipeline. A combined region of interest (ROI and whole brain approach was used to detect any sub-regional and vertex-level differences after removing effects of age and total GM volume. Correlation analyses were performed on behavioral data.While IBS as a group did not show significant differences in CT compared to HCs, sex related differences were observed both within the IBS and the HC groups. When female IBS patients were compared to female HCs, whole brain analysis showed significant CT increase in somatosensory and primary motor cortex, as well as CT decrease in bilateral subgenual anterior cingulate cortex (sgACC. The ROI analysis showed significant regional CT decrease in bilateral subregions of insular cortex, while CT decrease in cingulate was limited to left sgACC, accounting for the effect of age and GM volume. Several measures of IBS symptom severity showed significant correlation with CT changes in female IBS patients.Significant, sex related differences in CT are present in both HCs and in IBS patients. The biphasic neuroplastic changes in female IBS patients are related to symptom severity.

  15. Early cortical bone healing around loaded titanium implants: a histological study in the rabbit.

    Science.gov (United States)

    Slaets, Elke; Naert, Ignace; Carmeliet, Geert; Duyck, Joke

    2009-02-01

    To identify the role of immediate implant loading on the early phases of the bone healing responses. Implants were placed in rabbit tibial diaphyses and left to heal for 3, 7, 14, 28 or 42 days. Half of the animals received an immediate loading protocol of 2.2 N at 3 Hz for 1800 cycles and 5 days/week, whereas the others served as unloaded controls. Histological assessment was combined with histomorphometrical measurements. At early time-points, an endosteal and periosteal new bone formation was found, while the cortex itself contained damaged osteocytes. At later time-points, new bone formation was also found at the cortical level itself. Differences between groups were found mainly in this new bone formation process, with larger reactions for the endosteal and periosteal bone in the loaded group after 28 and 42 days, respectively. At the end-point of the experiment, bone formation at the cortical level was reduced in the loaded group compared with the control group. These results show that the immediate loading protocol caused no differences in the sequential events leading to osseointegration in cortical bone. However, the processes of new bone formation originating from the endosteum and the periosteum lasted longer compared with the unloaded controls.

  16. Femoral cortical index: an indicator of poor bone quality in patient with hip fracture.

    Science.gov (United States)

    Feola, M; Rao, C; Tempesta, V; Gasbarra, E; Tarantino, U

    2015-10-01

    Osteoporosis is a common disease in elderly, characterized by poor bone quality as a result of alterations affecting trabecular bone. However, recent studies have described also an important role of alterations of cortical bone in the physiopathology of osteoporosis. Although dual-energy X-ray absorptiometry (DXA) is a valid method to assess bone mineral density, in the presence of comorbidities real bone fragility is unable to be evaluated. The number of hip fractures is rising, especially in people over 85 years old. The aim is to evaluate an alternative method so that it can indicate fracture risk, independent of bone mineral density (BMD). Femoral cortical index (FCI) assesses cortical bone stock using femur X-ray. A retrospective study has been conducted on 152 patients with hip fragility fractures. FCI has been calculated on fractured femur and on the opposite side. The presence of comorbidities, osteoporosis risk factors, vitamin D levels, and BMD have been analyzed for each patient. Average values of FCI have been 0.42 for fractured femurs and 0.48 at the opposite side with a statistically significant difference (p = 0.002). Patients with severe hypovitaminosis D had a minor FCI compared to those with moderate deficiency (0.41 vs. 0.46, p hip fractures has been found. FCI could be a useful tool to evaluate bone fragility and to predict fracture risk even in the normal and osteopenic BMD patients.

  17. Variations of mechanical property of out circumferential lamellae in cortical bone along the radial by nanoindentation

    Directory of Open Access Journals (Sweden)

    Xingdong Sun

    2016-11-01

    Full Text Available Because the out circumferential lamellae have a special protective effect on the cortical bone, it is very important to understand the variations of the mechanical property of the out circumferential lamellae in cortical bone. For the purpose, the elasticity modulus and hardness of out circumferential lamellae in cortical bone were investigated in two orthogonal planes by nanoindentation, and the comparisons were made for both elasticity modulus and hardness between the two orthogonal planes. From the experiments, the decreasing trend was discovered for elasticity modulus from inside to outside in the transverse plane and ruleless variations tendency was presented in the longitudinal plane. The hardness presented the same variations in two orthogonal planes with elasticity modulus in respective plane. In the same layer, the elasticity modulus in the transverse plane was higher than that in the longitudinal plane, and the difference values between them turned to be smaller. In contrast, the hardness in the longitudinal plane was higher than that in the transverse plane in all the layers. From the heterogeneity and the microstructure of the material, the influence factors were discussed. A soft to hard structure model was put forward, and the coordinating protection mechanism of buffer and support was described. Investigation of variations of mechanical properties of out circumferential lamellae in cortical bone can provide some new understanding in researches of fracture of bone, interface load effect and design of bone graft.

  18. The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone

    DEFF Research Database (Denmark)

    Ding, Ming; Danielsen, Carl C; Overgaard, Søren

    mechanical properties in the glucocorticoid-2. In conclusion, 7 months glucocorticoid treatment with malnutrition had significant impact on cortical microarchitecture of sheep femur midshaft. These changes occurred particularly 3 months after the glucocorticoid cessation suggesting a delayed effect......The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone – Validation of large animal model for tissue engineering and biomaterial research Ming Ding,1* Carl Christian Danielsen,2 Søren Overgaard1 1Orthopaedic Research Laboratory...

  19. The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone

    DEFF Research Database (Denmark)

    Ding, Ming; Danielsen, Carl C; Overgaard, Søren

    2010-01-01

    The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone – Validation of large animal model for tissue engineering and biomaterial research Ming Ding,1* Carl Christian Danielsen,2 Søren Overgaard1 1Orthopaedic Research Laboratory...... treatment. Group 3 was left untreated and served as the controls. All sheep received restricted diet with low calcium and phosphorus. At sacrifice, cortical bone samples from the femur midshaft of sheep were harvested, micro-CT scanned and tested in 3 point bending and in tensile. Bone collagen and mineral...... mechanical properties in the glucocorticoid-2. In conclusion, 7 months glucocorticoid treatment with malnutrition had significant impact on cortical microarchitecture of sheep femur midshaft. These changes occurred particularly 3 months after the glucocorticoid cessation suggesting a delayed effect...

  20. Changes in Cortical Thickness in 6-Year-Old Children Open Their Mind to a Global Vision of the World

    Directory of Open Access Journals (Sweden)

    Nicolas Poirel

    2014-01-01

    Full Text Available Even if objectively presented with similar visual stimuli, children younger than 6 years of age exhibit a strong attraction to local visual information (e.g., the trees, whereas children older than 6 years of age, similar to adults, exhibit a visual bias toward global information (e.g., the forest. Here, we studied the cortical thickness changes that underlie this bias shift from local to global visual information. Two groups, matched for age, gender, and handedness, were formed from a total of 30 children who were 6 years old, and both groups performed a traditional global/local visual task. The first group presented a local visual bias, and the other group presented a global visual bias. The results indicated that, compared with the local visual bias group, children with a global visual bias exhibited (1 decreased cortical thickness in the bilateral occipital regions and (2 increased cortical thickness in the left frontoparietal regions. These findings constitute the first structural study that supports the view that both synaptic pruning (i.e., decreased cortical thickness and expansion mechanisms (i.e., increased cortical thickness cooccur to allow healthy children to develop a global perception of the visual world.

  1. Longitudinal trajectories of cortical thickness as a biomarker for psychosis in individuals with 22q11.2 deletion syndrome.

    Science.gov (United States)

    Ramanathan, Seetha; Mattiaccio, Leah M; Coman, Ioana L; Botti, Jo-Anna C; Fremont, Wanda; Faraone, Stephen V; Antshel, Kevin M; Kates, Wendy R

    2016-12-14

    22q11.2 deletion syndrome (DS) or velo-cardio-facial syndrome (VCFS) is a genetic condition that has been identified as the highest genetic risk factor for developing psychotic illnesses. This unique biological nature of 22q11DS provides a valuable opportunity to explore predictive biomarkers of psychosis. In this study, we examined the relationship of cortical thickness and surface area between various brain regions and prodromal symptoms of psychosis. 75 probands with 22q11DS, 32 age-matched controls and 28 siblings underwent MRIs over 2 or 3 timepoints. Longitudinal mixed model regression analyses, with age as an interaction variable, were carried out to study the differences in longitudinal trajectories of change in average cortical thickness and surface area over 6-9years. Similar analyses were carried out to examine the relationship with positive prodromal symptoms of psychosis. Significant differences were noted in the inferior and superior parietal regions in both the average thickness and longitudinal change in cortical thickness with age between the probands and controls. Significant associations were also noted between regions in the frontal cortex and positive prodromal symptoms among probands. No associations were noted with cortical surface area. Our results indicate that individuals with 22q11DS who develop positive prodromal symptoms demonstrate differential longitudinal trajectories of cortical thickness in some regions of the frontal lobe. Our results suggest that the pruning stage associated with adolescent brain development may be disrupted. Copyright © 2016. Published by Elsevier B.V.

  2. Modalities for Visualization of Cortical Bone Remodeling: The Past, Present, and Future.

    Science.gov (United States)

    Harrison, Kimberly D; Cooper, David M L

    2015-01-01

    Bone's ability to respond to load-related phenomena and repair microdamage is achieved through the remodeling process, which renews bone by activating groups of cells known as basic multicellular units (BMUs). The products of BMUs, secondary osteons, have been extensively studied via classic two-dimensional techniques, which have provided a wealth of information on how histomorphology relates to skeletal structure and function. Remodeling is critical in maintaining healthy bone tissue; however, in osteoporotic bone, imbalanced resorption results in increased bone fragility and fracture. With increasing life expectancy, such degenerative bone diseases are a growing concern. The three-dimensional (3D) morphology of BMUs and their correlation to function, however, are not well-characterized and little is known about the specific mechanisms that initiate and regulate their activity within cortical bone. We believe a key limitation has been the lack of 3D information about BMU morphology and activity. Thus, this paper reviews methodologies for 3D investigation of cortical bone remodeling and, specifically, structures associated with BMU activity (resorption spaces) and the structures they create (secondary osteons), spanning from histology to modern ex vivo imaging modalities, culminating with the growing potential of in vivo imaging. This collection of papers focuses on the theme of "putting the 'why' back into bone architecture." Remodeling is one of two mechanisms "how" bone structure is dynamically modified and thus an improved 3D understanding of this fundamental process is crucial to ultimately understanding the "why."

  3. Insulin Resistance Is Associated With Smaller Cortical Bone Size in Nondiabetic Men at the Age of Peak Bone Mass.

    Science.gov (United States)

    Verroken, Charlotte; Zmierczak, Hans-Georg; Goemaere, Stefan; Kaufman, Jean-Marc; Lapauw, Bruno

    2017-06-01

    In type 2 diabetes mellitus, fracture risk is increased despite preserved areal bone mineral density. Although this apparent paradox may in part be explained by insulin resistance affecting bone structure and/or material properties, few studies have investigated the association between insulin resistance and bone geometry. We aimed to explore this association in a cohort of nondiabetic men at the age of peak bone mass. Nine hundred ninety-six nondiabetic men aged 25 to 45 years were recruited in a cross-sectional, population-based sibling pair study at a university research center. Insulin resistance was evaluated using the homeostasis model assessment of insulin resistance (HOMA-IR), with insulin and glucose measured from fasting serum samples. Bone geometry was assessed using peripheral quantitative computed tomography at the distal radius and the radial and tibial shafts. In age-, height-, and weight-adjusted analyses, HOMA-IR was inversely associated with trabecular area at the distal radius and with cortical area, periosteal and endosteal circumference, and polar strength strain index at the radial and tibial shafts (β ≤ -0.13, P insulin-like growth factor 1, or sex steroid levels. In this cohort of nondiabetic men at the age of peak bone mass, insulin resistance is inversely associated with trabecular and cortical bone size. These associations persist after adjustment for body composition, muscle size or function, or sex steroid levels, suggesting an independent effect of insulin resistance on bone geometry.

  4. A preliminary investigation of the dynamic viscoelastic relaxation of bovine cortical bone

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    Loete T.J.C.

    2015-01-01

    Full Text Available A new experimental approach is proposed to characterize the dynamic viscoelastic relaxation behaviour of cortical bone. Theoretical models are presented to show that a linear viscoelastic material, when allowed to relax between two long elastic bars, will produce stress, strain and strain rate histories that contain characteristic features. Furthermore, typical experimental results are presented to show that these characteristic features are observed during split Hopkinson bar tests on bovine cortical bone using a Cone-in-Tube striker. The interpretation of this behaviour in the context of a standard linear viscoelastic model is discussed.

  5. Nonlinear hierarchical multiscale modeling of cortical bone considering its nanoscale microstructure.

    Science.gov (United States)

    Ghanbari, J; Naghdabadi, R

    2009-07-22

    We have used a hierarchical multiscale modeling scheme for the analysis of cortical bone considering it as a nanocomposite. This scheme consists of definition of two boundary value problems, one for macroscale, and another for microscale. The coupling between these scales is done by using the homogenization technique. At every material point in which the constitutive model is needed, a microscale boundary value problem is defined using a macroscopic kinematical quantity and solved. Using the described scheme, we have studied elastic properties of cortical bone considering its nanoscale microstructural constituents with various mineral volume fractions. Since the microstructure of bone consists of mineral platelet with nanometer size embedded in a protein matrix, it is similar to the microstructure of soft matrix nanocomposites reinforced with hard nanostructures. Considering a representative volume element (RVE) of the microstructure of bone as the microscale problem in our hierarchical multiscale modeling scheme, the global behavior of bone is obtained under various macroscopic loading conditions. This scheme may be suitable for modeling arbitrary bone geometries subjected to a variety of loading conditions. Using the presented method, mechanical properties of cortical bone including elastic moduli and Poisson's ratios in two major directions and shear modulus is obtained for different mineral volume fractions.

  6. Sex, age, and cognitive correlates of asymmetries in thickness of the cortical mantle across the life span

    DEFF Research Database (Denmark)

    Plessen, Kerstin J; Hugdahl, Kenneth; Bansal, Ravi

    2014-01-01

    lateral, dorsal, and mesial surfaces of the frontal lobe, extending into primary sensory, superior parietal, and anterior superior temporal cortices. A right > left asymmetry was present in the lateral, mesial, and dorsal surfaces of the posterior temporal, parietal, and occipital cortices, as well...... as in the entire inferior surface of the brain. An exaggerated left > right asymmetry was detected in females in anterior brain regions, and an exaggerated right > left asymmetry was detected in males in the orbitofrontal, inferior parietal, and inferior occipital cortices. Weaker moderating effects of sex were...... scattered along the mesial surface of the brain. Age significantly moderated asymmetry measures in the inferior sensorimotor, inferior parietal, posterior temporal, and inferior occipital cortices. The age × asymmetry interaction derived from a steeper decline in cortical thickness with age in the right...

  7. Effects of Habitual Physical Activity and Fitness on Tibial Cortical Bone Mass, Structure and Mass Distribution in Pre-pubertal Boys and Girls: The Look Study.

    Science.gov (United States)

    Duckham, Rachel L; Rantalainen, Timo; Ducher, Gaele; Hill, Briony; Telford, Richard D; Telford, Rohan M; Daly, Robin M

    2016-07-01

    Targeted weight-bearing activities during the pre-pubertal years can improve cortical bone mass, structure and distribution, but less is known about the influence of habitual physical activity (PA) and fitness. This study examined the effects of contrasting habitual PA and fitness levels on cortical bone density, geometry and mass distribution in pre-pubertal children. Boys (n = 241) and girls (n = 245) aged 7-9 years had a pQCT scan to measure tibial mid-shaft total, cortical and medullary area, cortical thickness, density, polar strength strain index (SSIpolar) and the mass/density distribution through the bone cortex (radial distribution divided into endo-, mid- and pericortical regions) and around the centre of mass (polar distribution). Four contrasting PA and fitness groups (inactive-unfit, inactive-fit, active-unfit, active-fit) were generated based on daily step counts (pedometer, 7-days) and fitness levels (20-m shuttle test and vertical jump) for boys and girls separately. Active-fit boys had 7.3-7.7 % greater cortical area and thickness compared to inactive-unfit boys (P < 0.05), which was largely due to a 6.4-7.8 % (P < 0.05) greater cortical mass in the posterior-lateral, medial and posterior-medial 66 % tibial regions. Cortical area was not significantly different across PA-fitness categories in girls, but active-fit girls had 6.1 % (P < 0.05) greater SSIpolar compared to inactive-fit girls, which was likely due to their 6.7 % (P < 0.05) greater total bone area. There was also a small region-specific cortical mass benefit in the posterior-medial 66 % tibia cortex in active-fit girls. Higher levels of habitual PA-fitness were associated with small regional-specific gains in 66 % tibial cortical bone mass in pre-pubertal children, particularly boys.

  8. Bone lead (Pb) content at the tibia is associated with thinner distal tibia cortices and lower volumetric bone density in postmenopausal women.

    Science.gov (United States)

    Wong, Andy K O; Beattie, Karen A; Bhargava, Aakash; Cheung, Marco; Webber, Colin E; Chettle, David R; Papaioannou, Alexandra; Adachi, Jonathan D

    2015-10-01

    Conflicting evidence suggests that bone lead or blood lead may reduce areal bone mineral density (BMD). Little is known about how lead at either compartment affects bone structure. This study examined postmenopausal women (N=38, mean age 76 ± 8, body mass index (BMI): 26.74 ± 4.26 kg/m(2)) within the Hamilton cohort of the Canadian Multicentre Osteoporosis Study (CaMos), measuring bone lead at 66% of the non-dominant leg and at the calcaneus using (109)Cadmium X-ray fluorescence. Volumetric BMD and structural parameters were obtained from peripheral quantitative computed tomography images (200 μm in-plane resolution, 2.3 ± 0.5mm slice thickness) of the same 66% site and of the distal 4% site of the tibia length. Blood lead was measured using atomic absorption spectrometry and blood-to-bone lead partition coefficients (PBB, log ratio) were computed. Multivariable linear regression examined each of bone lead at the 66% tibia, calcaneus, blood lead and PBB as related to each of volumetric BMD and structural parameters, adjusting for age and BMI, diabetes or antiresorptive therapy. Regression coefficients were reported along with 95% confidence intervals. Higher amounts of bone lead at the tibia were associated with thinner distal tibia cortices (-0.972 (-1.882, -0.061) per 100 μg Pb/g of bone mineral) and integral volumetric BMD (-3.05 (-6.05, -0.05) per μg Pb/g of bone mineral). A higher PBB was associated with larger trabecular separation (0.115 (0.053, 0.178)), lower trabecular volumetric BMD (-26.83 (-50.37, -3.29)) and trabecular number (-0.08 (-0.14, -0.02)), per 100 μg Pb/g of bone mineral after adjusting for age and BMI, and remained significant while accounting for diabetes or use of antiresorptives. Total lead exposure activities related to bone lead at the calcaneus (8.29 (0.11, 16.48)) and remained significant after age and antiresorptives-adjustment. Lead accumulated in bone can have a mild insult on bone structure; but greater partitioning of lead

  9. Cortical Thickness Abnormalities in Autism Spectrum Disorders Through Late Childhood, Adolescence, and Adulthood: A Large-Scale MRI Study.

    Science.gov (United States)

    Khundrakpam, Budhachandra S; Lewis, John D; Kostopoulos, Penelope; Carbonell, Felix; Evans, Alan C

    2017-03-01

    Neuroimaging studies in autism spectrum disorders (ASDs) have provided inconsistent evidence of cortical abnormality. This is probably due to the small sample sizes used in most studies, and important differences in sample characteristics, particularly age, as well as to the heterogeneity of the disorder. To address these issues, we assessed abnormalities in ASD within the Autism Brain Imaging Data Exchange data set, which comprises data from approximately 1100 individuals (~6-55 years). A subset of these data that met stringent quality control and inclusion criteria (560 male subjects; 266 ASD; age = 6-35 years) were used to compute age-specific differences in cortical thickness in ASD and the relationship of any such differences to symptom severity of ASD. Our results show widespread increased cortical thickness in ASD, primarily left lateralized, from 6 years onwards, with differences diminishing during adulthood. The severity of symptoms related to social affect and communication correlated with these cortical abnormalities. These results are consistent with the conjecture that developmental patterns of cortical thickness abnormalities reflect delayed cortical maturation and highlight the dynamic nature of morphological abnormalities in ASD. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  10. The effect of high voltage, high frequency pulsed electric field on slain ovine cortical bone.

    Science.gov (United States)

    Asgarifar, Hajarossadat; Oloyede, Adekunle; Zare, Firuz

    2014-04-01

    High power, high frequency pulsed electric fields known as pulsed power (PP) has been applied recently in biology and medicine. However, little attention has been paid to investigate the application of pulse power in musculoskeletal system and its possible effect on functional behavior and biomechanical properties of bone tissue. This paper presents the first research investigating whether or not PP can be applied safely on bone tissue as a stimuli and what will be the possible effect of these signals on the characteristics of cortical bone by comparing the mechanical properties of this type of bone pre and post expose to PP and in comparison with the control samples. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses (up to 500 V and 10 kHz). The functional behavior of bone in response to pulse power excitation was elucidated by applying compressive loading until failure. The stiffness, failure stress (strength) and the total fracture energy (bone toughness) were determined as a measure of the main bone characteristics. Furthermore, an ultrasonic technique was applied to determine and comprise bone elasticity before and after pulse power stimulation. The elastic property of cortical bone samples appeared to remain unchanged following exposure to pulse power excitation for all three orthogonal directions obtained from ultrasonic technique and similarly from the compression test. Nevertheless, the compressive strength and toughness of bone samples were increased when they were exposed to 66 h of high power pulsed electromagnetic field compared to the control samples. As the toughness and the strength of the cortical bone tissue are directly associated with the quality and integrity of the collagen matrix whereas its stiffness is primarily related to bone mineral content these overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network

  11. Cortical thickness, surface area and volume measures in Parkinson's disease, multiple system atrophy and progressive supranuclear palsy.

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    Amanda Worker

    Full Text Available Parkinson's disease (PD, Multiple System Atrophy (MSA and Progressive Supranuclear Palsy (PSP are neurodegenerative diseases that can be difficult to distinguish clinically. The objective of the current study was to use surface-based analysis techniques to assess cortical thickness, surface area and grey matter volume to identify unique morphological patterns of cortical atrophy in PD, MSA and PSP and to relate these patterns of change to disease duration and clinical features.High resolution 3D T1-weighted MRI volumes were acquired from 14 PD patients, 18 MSA, 14 PSP and 19 healthy control participants. Cortical thickness, surface area and volume analyses were carried out using the automated surface-based analysis package FreeSurfer (version 5.1.0. Measures of disease severity and duration were assessed for correlation with cortical morphometric changes in each clinical group.Results show that in PSP, widespread cortical thinning and volume loss occurs within the frontal lobe, particularly the superior frontal gyrus. In addition, PSP patients also displayed increased surface area in the pericalcarine. In comparison, PD and MSA did not display significant changes in cortical morphology.These results demonstrate that patients with clinically established PSP exhibit distinct patterns of cortical atrophy, particularly affecting the frontal lobe. These results could be used in the future to develop a useful clinical application of MRI to distinguish PSP patients from PD and MSA patients.

  12. Reduced frontal cortex thickness and cortical volume associated with pathological narcissism.

    Science.gov (United States)

    Mao, Yu; Sang, Na; Wang, Yongchao; Hou, Xin; Huang, Hui; Wei, Dongtao; Zhang, Jinfu; Qiu, Jiang

    2016-07-22

    Pathological narcissism is often characterized by arrogant behavior, a lack of empathy, and willingness to exploit other individuals. Generally, individuals with high levels of narcissism are more likely to suffer mental disorders. However, the brain structural basis of individual pathological narcissism trait among healthy people has not yet been investigated with surface-based morphometry. Thus, in this study, we investigated the relationship between cortical thickness (CT), cortical volume (CV), and individual pathological narcissism in a large healthy sample of 176 college students. Multiple regression was used to analyze the correlation between regional CT, CV, and the total Pathological Narcissism Inventory (PNI) score, adjusting for age, sex, and total intracranial volume. The results showed that the PNI score was significantly negatively associated with CT and CV in the right dorsolateral prefrontal cortex (DLPFC, key region of the central executive network, CEN), which might be associated with impaired emotion regulation processes. Furthermore, the PNI score showed significant negative associations with CV in the right postcentral gyrus, left medial prefrontal cortex (MPFC), and the CT in the right inferior frontal cortex (IFG, overlap with social brain network), which may be related to impairments in social cognition. Together, these findings suggest a unique structural basis for individual differences in pathological narcissism, distributed across different gray matter regions of the social brain network and CEN. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  13. Focal Cortical Thickness Correlates of Exceptional Memory Training in Vedic Priests

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    Giridhar Padmanabhan Kalamangalam

    2014-10-01

    Full Text Available The capacity for semantic memory – the ability to acquire and store knowledge of the world - is highly developed in the human brain. In particular, semantic memory assimilated through an auditory route may be a uniquely human capacity. One method of obtaining neurobiological insight into auditory semantic memory mechanisms is through the study of experts. In this work, we study a group of Hindu Vedic priests, whose religious training requires the memorization of vast tracts of scriptural texts through an oral tradition, recalled spontaneously during a lifetime of subsequent spiritual practice. We demonstrate focal increases of cortical thickness in the dominant prefrontal lobe and non-dominant temporal lobe in Vedic priests, in comparison to a group of matched controls. The findings are relevant to current hypotheses regarding cognitive processes underlying storage and recall of long-term declarative memory.

  14. Modalities for visualization of cortical bone remodeling: the past, present and near future

    Directory of Open Access Journals (Sweden)

    Kimberly Dawn Harrison

    2015-08-01

    Full Text Available Bone’s ability to respond to load-related phenomena and repair microdamage is achieved through the remodeling process which renews bone by activating groups of cells known as Basic Multicellular Units (BMUs. The products of BMUs, secondary osteons, have been extensively studied via classic two-dimensional (2D techniques which have provided a wealth of information on how histomorphology relates to skeletal structure and function. Remodeling is critical in maintaining healthy bone tissue; however, in osteoporotic bone imbalanced resorption results in increased bone fragility and fracture. With increasing life expectancy, such degenerative bone diseases are a growing concern. The three-dimensional (3D morphology of BMUs and their correlation to function, however, are not well characterized and little is known about the specific mechanisms that initiate and regulate their activity within cortical bone. We believe a key limitation has been the lack 3D information about BMU morphology and activity. Thus, this paper reviews methodologies for 3D investigation of cortical bone remodeling and, specifically, structures associated with BMU activity (resorption spaces and the structures they create (secondary osteons, spanning from histology to modern ex vivo imaging modalities, culminating with the growing potential of in vivo imaging. This collection of papers focuses on the theme of putting the why back into bone archytecture. Remodeling is one of two mechanisms how bone structure is dynamically modified and thus an improved 3D understanding of this fundamental process is crucial to ultimately understanding the why.

  15. Effects of deleting cannabinoid receptor-2 on mechanical and material properties of cortical and trabecular bone

    Directory of Open Access Journals (Sweden)

    Aysha B. Khalid

    2015-12-01

    Full Text Available Cnr2 is one of two cannabinoid receptors known to regulate bone metabolism. Here, we compared the whole bone properties of femora and tibiae from three-month-old Cnr2−/- mice with wild-type controls using a C57BL/6 background. Bending stiffness was measured by three-point bending. The elastic modulus, density and mineral content were measured using ultrasound, Archimedes’ principle and ashing. Micro-CT was used to measure the second moment of area, inner and outer perimeters of the cortical shaft and trabecular parameters. Deleting Cnr2 increased the bending stiffness by increasing the second moment of area. Bone from affected male mice had a greater modulus than controls, although no difference was observed in females. The fractional volume of trabecular bone was greater in Cnr2−/- females than controls, while no difference was seen in males. These data indicate that inactivating Cnr2 increases the amount of cortical bone in both males and females at 3 months of age, but the effect on trabecular bone is different in the two sexes. These findings extend previous studies looking only at trabecular bone and provide further support for the possible use of Cnr2 antagonists for improving bone properties that may be of value in the treatment of bone disorders.

  16. Implant design and its effects on osseointegration over time within cortical and trabecular bone.

    Science.gov (United States)

    Beutel, Bryan G; Danna, Natalie R; Granato, Rodrigo; Bonfante, Estevam A; Marin, Charles; Tovar, Nick; Suzuki, Marcelo; Coelho, Paulo G

    2016-08-01

    Healing chambers present at the interface between implant and bone have become a target for improving osseointegration. The objective of the present study was to compare osseointegration of several implant healing chamber configurations at early time points and regions of interest within bone using an in vivo animal femur model. Six implants, each with a different healing chamber configuration, were surgically implanted into each femur of six skeletally mature beagle dogs (n = 12 implants per dog, total n = 72). The implants were harvested at 3 and 5 weeks post-implantation, non-decalcified processed to slides, and underwent histomorphometry with measurement of bone-to-implant contact (BIC) and bone area fraction occupied (BAFO) within healing chambers at both cortical and trabecular bone sites. Microscopy demonstrated predominantly woven bone at 3 weeks and initial replacement of woven bone by lamellar bone by 5 weeks. BIC and BAFO were both significantly increased by 5 weeks (p < 0.001), and significantly higher in cortical than trabecular bone (p < 0.001). The trapezoidal healing chamber design demonstrated a higher BIC than other configurations. Overall, a strong temporal and region-specific dependence of implant osseointegration in femurs was noted. Moreover, the findings suggest that a trapezoidal healing chamber configuration may facilitate the best osseointegration. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1091-1097, 2016.

  17. Prostaglandin E2 Increased Rat Cortical Bone Mass When Administered Immediately Following Ovariectomy

    Science.gov (United States)

    Ke, Hua Zhu; Jee, Webster S.S.; Zeng, Qing Qiang; Li, Mei; Lin, Bai Yun

    1993-01-01

    To investigate the effects of ovariectomy and the simultaneous administration of prostaglandin E2 (PGE2) on rat tibial shaft cortical bone histomorphometry, thirty-five 3 month-old female Sprague-Dawley rats were either ovariectomized (OVX), or sham ovariectomy (sham-OVX). The OVX rats were divided into three groups and treated with 0, 1 and 6 mg PGE2/kg/day for 90 days. The double fluorescent labeled undecalcified tibial shaft cross sections (proximal to the tibiofibular junction) of all the subjects were used for histomorphometry analysis. No differences in cross-sectional area and cortical bone area were found between sham-OVX and OVX controls, but OVX increased marrow area, intracortical porosity area and endocortical eroded perimeter. Periosteal and endocortical bone formation rates decreased with aging yet OVX prevented these changes. These OVX-induced increases in marrow area and endocortical eroded perimeter were prevented by 1 mg PGE2/kg/day treatment and added bone to periosteal and endocortical surfaces and to the marrow cavity. At the 6 mg/kg/day dose level, PGE2-treated OVX rats increased total tissue area, cortical bone area, marrow trabmular bone area, minimal cortical width and intracortical porosity area, and decreased marrow area compared to basal, sham-OVX and OVX controls. In addition, periosteal bone formation was elevated in the 6 mg PGE2/kg/day-treated OVX rats compared to OVX controls. Endocortical eroded perimeter increased from basal and sham-OVX control levels, but decreased from OVX control levels in the 6 mg PGE2/kg/day-treated OVX rats. Our study confirmed that ovariectomy does not cause osteopenia in tibial shaft cortical bone in rats, but it does stimulate endocortical bone resorption and enlarges marrow area. The new findings from the present study demonstrate that PGE2 prevents the OVX-induced increases in endocortical bone resorption and marrow area and adds additional bone to periosteal and endocortical surfaces and to marrow

  18. The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone.

    Science.gov (United States)

    Ding, Ming; Danielsen, Carl Christian; Overgaard, Søren

    2012-06-01

    In this study, 18 female skeletally mature sheep were randomly allocated into three groups of six each. Group 1 (glucocorticoid-1) received prednisolone treatment (0.60 mg/kg/day, five times weekly) for 7 months. Group 2 (glucocorticoid-2) received the same treatment regime followed by observation of 3 months without treatment. Group 3 was left untreated and served as controls. All sheep received a restricted diet with low calcium and phosphorus. At sacrifice, cortical bone samples from the femur midshaft of each sheep were harvested, micro-CT scanned and subjected to three-point bending and tensile strength testing. Bone collagen and mineral were determined. Cortical porosity was significantly increased in the glucocorticoid-2 compared with the glucocorticoid-1 and control groups. Apparent density was significantly decreased in the glucocorticoid-2 compared with the glucocorticoid-1 group. Collagen content was significantly increased in the glucocorticoid-2 compared with the glucocorticoid-1 and control groups. Bone mineral content did not differ between the groups. Neither the three-point bending mechanical properties nor the tensile mechanical properties differed significantly between the groups, while there was a trend towards decreasing bending mechanical properties in the glucocorticoid-2 group. In conclusion, 7 months of glucocorticoid treatment with malnutrition had a significant impact on the cortical microarchitecture of the sheep femur midshaft. These observed changes occurred 3 months after glucocorticoid cessation, suggesting a delayed effect of glucocorticoid on cortical bone. Thus, changes in cortical bone beyond cancellous bone might further increase fracture risk in patients treated with glucocorticoids. This model might be used as a glucocorticoid-induced osteoporotic model for orthopaedic biomaterial, joint prosthesis and medical device researches.

  19. Experimental and numerical analysis of Izod impact test of cortical bone tissue

    Science.gov (United States)

    Abdel-Wahab, A. A.; Silberschmidt, V. V.

    2012-05-01

    Bones can only sustain loads until a certain limit, beyond which they fail. Usually, the reasons for bone fracture are traumatic falls, sports injuries, and engagement in transport or industrial accidents. A proper treatment of bones and prevention of their fracture can be supported by in-depth understanding of deformation and fracture behavior of this tissue in such dynamic events. In this paper, a combination of experimental and numerical analysis was carried out in order to comprehend the fracture behavior of cortical bone tissue. Experimental tests were performed to study the transient dynamic behavior of cortical bone tissue under impact bending loading. The variability of absorbed energy for different cortex positions and notch depths was studied using Izod impact tests. Also, Extended Finite-Element Method implemented into the commercial finite-element software Abaqus was used to simulate the crack initiation and growth processes in a cantilever beam of cortical bone exposed to impact loading using the Izod loading scheme. The simulation results show a good agreement with the experimental data.

  20. Non-nuclear-initiated actions of the estrogen receptor protect cortical bone mass.

    Science.gov (United States)

    Bartell, Shoshana M; Han, Li; Kim, Ha-neui; Kim, Sung Hoon; Katzenellenbogen, John A; Katzenellenbogen, Benita S; Chambliss, Ken L; Shaul, Philip W; Roberson, Paula K; Weinstein, Robert S; Jilka, Robert L; Almeida, Maria; Manolagas, Stavros C

    2013-04-01

    Extensive evidence has suggested that at least some of the effects of estrogens on bone are mediated via extranuclear estrogen receptor α signaling. However, definitive proof for this contention and the extent to which such effects may contribute to the overall protective effects of estrogens on bone maintenance have remained elusive. Here, we investigated the ability of a 17β-estradiol (E2) dendrimer conjugate (EDC), incapable of stimulating nuclear-initiated actions of estrogen receptor α, to prevent the effects of ovariectomy (OVX) on the murine skeleton. We report that EDC was as potent as an equimolar dose of E2 in preventing bone loss in the cortical compartment that represents 80% of the entire skeleton, but was ineffective on cancellous bone. In contrast, E2 was effective in both compartments. Consistent with its effect on cortical bone mass, EDC partially prevented the loss of both vertebral and femoral strength. In addition, EDC, as did E2, prevented the OVX-induced increase in osteoclastogenesis, osteoblastogenesis, and oxidative stress. Nonetheless, the OVX-induced decrease in uterine weight was unaltered by EDC but was restored by E2. These results demonstrate that the protection of cortical bone mass by estrogens is mediated, at least in part, via a mechanism that is distinct from the classic mechanism of estrogen action on reproductive organs.

  1. How Tough is Human Cortical Bone? In-Situ Measurements on Realistically Short Cracks

    Energy Technology Data Exchange (ETDEWEB)

    Ritchie, Robert O; Koester, K. J.; Ager III, J. W.; Ritchie, R.O.

    2008-05-10

    Bone is more difficult to break than to split. Although this is well known, and many studies exist on the behavior of long cracks in bone, there is a need for data on the orientation-dependent crack-growth resistance behavior of human cortical bone which accurately assesses its toughness at appropriate size-scales. Here we use in-situ mechanical testing in the scanning electron microscope and x-ray computed tomography to examine how physiologically-pertinent short (<600 mu m) cracks propagate in both the transverse and longitudinal orientations in cortical bone, using both crack-deflection/twist mechanics and nonlinear-elastic fracture mechanics to determine crack-resistance curves. We find that after only 500 mu m of cracking, the driving force for crack propagation was more than five times higher in the transverse (breaking) direction than in the longitudinal (splitting) direction due to major crack deflections/twists principally at cement sheathes. Indeed, our results show that the true transverse toughness of cortical bone is far higher than previously reported. However, the toughness in the longitudinal orientation, where cracks tend to follow the cement lines, is quite low at these small crack sizes; it is only when cracks become several millimeters in length that bridging mechanisms can develop leading to the (larger-crack) toughnesses generally quoted for bone.

  2. X-ray physics- and bone composition-based estimation of thickness characteristics from clinical mandibular radiographs.

    Science.gov (United States)

    Scheiner, Stefan; Hellmich, Christian; Müller, Christoph; Bonitz, Lars; Kober, Cornelia

    2015-10-01

    In dentistry, clinical radiographs (also called X-ray images) reflect the intensity loss of an X-ray when being transmitted through the mandibular objects, and this loss is quantified in terms of grey values. While such images are standardly used for pathology detection by the experienced dentist, we here present a new method for getting more quantitative information out of such 2D radiographs, "extending" them into the third dimension. This "extension" requires consistent combination of X-ray physics (namely, X-ray intensity loss quantification along paths orthogonal to the panoramic clinical image and X-ray attenuation averaging for composite materials) with anatomically known upper and lower limits of vascular porosities in cortical and trabecular bone compartments. Correspondingly computed ranges of overall organ thicknesses are extremely narrow, suggesting adequate estimation of thickness characteristics from 2D radiographic panoramas used clinically, while predicted cortical and trabecular thickness ranges vary by ±8.47% and ±16.13%, respectively. The proposed method also identifies variations between thicknesses at similar anatomical locations left and right of the face's symmetry axis, and molar regions turn out to be thicker than those close to incisors. This paves the way to more detailed diagnostic activities, e.g. in combination with Finite Element simulations.

  3. Structural alteration of the dorsal visual network in DLB patients with visual hallucinations: a cortical thickness MRI study.

    Science.gov (United States)

    Delli Pizzi, Stefano; Franciotti, Raffaella; Tartaro, Armando; Caulo, Massimo; Thomas, Astrid; Onofrj, Marco; Bonanni, Laura

    2014-01-01

    Visual hallucinations (VH) represent one of the core features in discriminating dementia with Lewy bodies (DLB) from Alzheimer's Disease (AD). Previous studies reported that in DLB patients functional alterations of the parieto-occipital regions were correlated with the presence of VH. The aim of our study was to assess whether morphological changes in specific cortical regions of DLB could be related to the presence and severity of VH. We performed a cortical thickness analysis on magnetic resonance imaging data in a cohort including 18 DLB patients, 15 AD patients and 14 healthy control subjects. Relatively to DLB group, correlation analysis between the cortical thickness and the Neuropsychiatric Inventory (NPI) hallucination item scores was also performed. Cortical thickness was reduced bilaterally in DLB compared to controls in the pericalcarine and lingual gyri, cuneus, precuneus, superior parietal gyrus. Cortical thinning was found bilaterally in AD compared to controls in temporal cortex including the superior and middle temporal gyrus, part of inferior temporal cortex, temporal pole and insula. Inferior parietal and supramarginal gyri were also affected bilaterally in AD as compared to controls. The comparison between DLB and AD evidenced cortical thinning in DLB group in the right posterior regions including superior parietal gyrus, precuneus, cuneus, pericalcarine and lingual gyri. Furthermore, the correlation analysis between cortical thickness and NPI hallucination item scores showed that the structural alteration in the dorsal visual regions including superior parietal gyrus and precuneus closely correlated with the occurrence and severity of VH. We suggest that structural changes in key regions of the dorsal visual network may play a crucial role in the physiopathology of VH in DLB patients.

  4. Structural alteration of the dorsal visual network in DLB patients with visual hallucinations: a cortical thickness MRI study.

    Directory of Open Access Journals (Sweden)

    Stefano Delli Pizzi

    Full Text Available Visual hallucinations (VH represent one of the core features in discriminating dementia with Lewy bodies (DLB from Alzheimer's Disease (AD. Previous studies reported that in DLB patients functional alterations of the parieto-occipital regions were correlated with the presence of VH. The aim of our study was to assess whether morphological changes in specific cortical regions of DLB could be related to the presence and severity of VH. We performed a cortical thickness analysis on magnetic resonance imaging data in a cohort including 18 DLB patients, 15 AD patients and 14 healthy control subjects. Relatively to DLB group, correlation analysis between the cortical thickness and the Neuropsychiatric Inventory (NPI hallucination item scores was also performed. Cortical thickness was reduced bilaterally in DLB compared to controls in the pericalcarine and lingual gyri, cuneus, precuneus, superior parietal gyrus. Cortical thinning was found bilaterally in AD compared to controls in temporal cortex including the superior and middle temporal gyrus, part of inferior temporal cortex, temporal pole and insula. Inferior parietal and supramarginal gyri were also affected bilaterally in AD as compared to controls. The comparison between DLB and AD evidenced cortical thinning in DLB group in the right posterior regions including superior parietal gyrus, precuneus, cuneus, pericalcarine and lingual gyri. Furthermore, the correlation analysis between cortical thickness and NPI hallucination item scores showed that the structural alteration in the dorsal visual regions including superior parietal gyrus and precuneus closely correlated with the occurrence and severity of VH. We suggest that structural changes in key regions of the dorsal visual network may play a crucial role in the physiopathology of VH in DLB patients.

  5. Negative correlation of cortical thickness with the severity and duration of abdominal pain in Asian women with irritable bowel syndrome.

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    Chua, Chian Sem; Bai, Chyi-Huey; Shiao, Chen-Yu; Hsu, Chien-Yeh; Cheng, Chiao-Wen; Yang, Kuo-Ching; Chiu, Hung-Wen; Hsu, Jung-Lung

    2017-01-01

    Irritable bowel syndrome (IBS) manifests as chronic abdominal pain. One pathophysiological theory states that the brain-gut axis is responsible for pain control in the intestine. Although several studies have discussed the structural changes in the brain of IBS patients, most of these studies have been conducted in Western populations. Different cultures and sexes experience different pain sensations and have different pain responses. Accordingly, we aimed to identify the specific changes in the cortical thickness of Asian women with IBS and to compare these data to those of non-Asian women with IBS. Thirty Asian female IBS patients (IBS group) and 39 healthy individuals (control group) were included in this study. Brain structural magnetic resonance imaging was performed. We used FreeSurfer to analyze the differences in the cortical thickness and their correlations with patient characteristics. The left cuneus, left rostral middle frontal cortex, left supramarginal cortex, right caudal anterior cingulate cortex, and bilateral insula exhibited cortical thinning in the IBS group compared with those in the controls. Furthermore, the brain cortical thickness correlated negatively the severity as well as duration of abdominal pain. Some of our findings differ from those of Western studies. In our study, all of the significant brain regions in the IBS group exhibited cortical thinning compared with those in the controls. The differences in cortical thickness between the IBS patients and controls may provide useful information to facilitate regulating abdominal pain in IBS patients. These findings offer insights into the association of different cultures and sexes with differences in cortical thinning in patients with IBS.

  6. Anxious/Depressed Symptoms are Linked to Right Ventromedial Prefrontal Cortical Thickness Maturation in Healthy Children and Young Adults

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    Ducharme, Simon; Albaugh, Matthew D.; Hudziak, James J.; Botteron, Kelly N.; Nguyen, Tuong-Vi; Truong, Catherine; Evans, Alan C.; Karama, Sherif; Ball, William S.; Byars, Anna Weber; Schapiro, Mark; Bommer, Wendy; Carr, April; German, April; Dunn, Scott; Rivkin, Michael J.; Waber, Deborah; Mulkern, Robert; Vajapeyam, Sridhar; Chiverton, Abigail; Davis, Peter; Koo, Julie; Marmor, Jacki; Mrakotsky, Christine; Robertson, Richard; McAnulty, Gloria; Brandt, Michael E.; Fletcher, Jack M.; Kramer, Larry A.; Yang, Grace; McCormack, Cara; Hebert, Kathleen M.; Volero, Hilda; Botteron, Kelly; McKinstry, Robert C.; Warren, William; Nishino, Tomoyuki; Almli, C. Robert; Todd, Richard; Constantino, John; McCracken, James T.; Levitt, Jennifer; Alger, Jeffrey; O'Neil, Joseph; Toga, Arthur; Asarnow, Robert; Fadale, David; Heinichen, Laura; Ireland, Cedric; Wang, Dah-Jyuu; Moss, Edward; Zimmerman, Robert A.; Bintliff, Brooke; Bradford, Ruth; Newman, Janice; Evans, Alan C.; Arnaoutelis, Rozalia; Pike, G. Bruce; Collins, D. Louis; Leonard, Gabriel; Paus, Tomas; Zijdenbos, Alex; Das, Samir; Fonov, Vladimir; Fu, Luke; Harlap, Jonathan; Leppert, Ilana; Milovan, Denise; Vins, Dario; Zeffiro, Thomas; Van Meter, John; Lange, Nicholas; Froimowitz, Michael P.; Botteron, Kelly; Almli, C. Robert; Rainey, Cheryl; Henderson, Stan; Nishino, Tomoyuki; Warren, William; Edwards, Jennifer L.; Dubois, Diane; Smith, Karla; Singer, Tish; Wilber, Aaron A.; Pierpaoli, Carlo; Basser, Peter J.; Chang, Lin-Ching; Koay, Chen Guan; Walker, Lindsay; Freund, Lisa; Rumsey, Judith; Baskir, Lauren; Stanford, Laurence; Sirocco, Karen; Gwinn-Hardy, Katrina; Spinella, Giovanna; McCracken, James T.; Alger, Jeffry R.; Levitt, Jennifer; O'Neill, Joseph

    2014-01-01

    The relationship between anxious/depressed traits and neuromaturation remains largely unstudied. Characterizing this relationship during healthy neurodevelopment is critical to understanding processes associated with the emergence of child/adolescent onset mood/anxiety disorders. In this study, mixed-effects models were used to determine longitudinal cortical thickness correlates of Child Behavior Checklist (CBCL) and Young Adult Self Report Anxious/Depressed scores in healthy children. Analyses included 341 subjects from 4.9 to 22.3 year-old with repeated MRI at up to 3 time points, at 2-year intervals (586 MRI scans). There was a significant “CBCL Anxious/Depressed by Age” interaction on cortical thickness in the right ventromedial prefrontal cortex (vmPFC), including the medial orbito-frontal, gyrus rectus, and subgenual anterior cingulate areas. Anxious/Depressed scores were negatively associated with thickness at younger ages (<9 years), but positively associated with thickness at older ages (15–22 years), with the shift in polarity occurring around age 12. This was secondary to a slower rate of vmPFC cortical thinning in subjects with higher scores. In young adults (18–22 years), Anxious/Depressed scores were also positively associated with precuneus/posterior cingulate cortical thickness. Potential neurobiological mechanisms underlying this maturation pattern are proposed. These results demonstrate the dynamic impact of age on relations between vmPFC and negative affect in the developing brain. PMID:23749874

  7. Experimental Investigations on Microcracks in Vibrational and Conventional Drilling of Cortical Bone

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    Yu Wang

    2013-01-01

    Full Text Available Bone drilling is widely used in orthopedic surgery. Microcracks will be generated in bone drilling, which may cause fatigue damages and stress fractures. Fresh bovine cortical bones were drilled via vibrational and conventional ways. Drilling operations were performed by a dynamic material testing machine, which can provide the vibration while maintaining uniform feed motion. The drill site and bone debris were observed through scanning electron microscope (SEM. The experimental results showed that fewer and shorter micro-cracks were formed in vibrational drilling than those formed in conventional way. And the surface morphology of bone debris from two different drilling ways was also quite different. It is expected that vibrational drilling in orthopedic surgery operation could decrease the microdamage to the bone, which could lower the incidence of stress fracture and contribute to the postoperative recovery.

  8. Using smooth particle hydrodynamics to investigate femoral cortical bone remodelling at the Haversian level.

    Science.gov (United States)

    Fernandez, J W; Das, R; Cleary, P W; Hunter, P J; Thomas, C D L; Clement, J G

    2013-01-01

    In the neck of the femur, about 70% of the strength is contributed by the cortical bone, which is the most highly stressed part of the structure and is the site where failure is almost certainly initiated. A better understanding of cortical bone remodelling mechanisms can help discern changes at this anatomical site, which are essential if an understanding of the mechanisms by which hips weaken and become vulnerable to fracture is to be gained. The aims of this study were to (i) examine a hypothesis that low strain fields arise because of subject-specific Haversian canal distributions causing bone resorption and reduced bone integrity and (ii) introduce the use of a meshless particle-based computational modelling approach SPH to capture bone remodelling features at the level of the Haversian canals. We show that bone remodelling initiated by strain at the Haversian level is highly influenced by the subject-specific pore distribution, bone density, loading and osteocyte density. SPH is shown to be effective at capturing the intricate bone pore shapes that evolved over time.

  9. Measuring metacarpal cortical bone by digital x-ray radiogrammetry: a step forward?

    NARCIS (Netherlands)

    Geusens, PP; Lems, W.F.

    2009-01-01

    Changes in metacarpal cortical bone mineral density (BMD) using digital x-ray radiogrammetry were studied in patients with early rheumatoid arthritis. After 1, 2, and 5 years, large BMD losses were found: -1.7%, -2.8%, and -5.6%, respectively. Elevated erythrocyte sedimentation rate and anti-cyclic

  10. Dyslexia and language impairment associated genetic markers influence cortical thickness and white matter in typically developing children.

    Science.gov (United States)

    Eicher, John D; Montgomery, Angela M; Akshoomoff, Natacha; Amaral, David G; Bloss, Cinnamon S; Libiger, Ondrej; Schork, Nicholas J; Darst, Burcu F; Casey, B J; Chang, Linda; Ernst, Thomas; Frazier, Jean; Kaufmann, Walter E; Keating, Brian; Kenet, Tal; Kennedy, David; Mostofsky, Stewart; Murray, Sarah S; Sowell, Elizabeth R; Bartsch, Hauke; Kuperman, Joshua M; Brown, Timothy T; Hagler, Donald J; Dale, Anders M; Jernigan, Terry L; Gruen, Jeffrey R

    2016-03-01

    Dyslexia and language impairment (LI) are complex traits with substantial genetic components. We recently completed an association scan of the DYX2 locus, where we observed associations of markers in DCDC2, KIAA0319, ACOT13, and FAM65B with reading-, language-, and IQ-related traits. Additionally, the effects of reading-associated DYX3 markers were recently characterized using structural neuroimaging techniques. Here, we assessed the neuroimaging implications of associated DYX2 and DYX3 markers, using cortical volume, cortical thickness, and fractional anisotropy. To accomplish this, we examined eight DYX2 and three DYX3 markers in 332 subjects in the Pediatrics Imaging Neurocognition Genetics study. Imaging-genetic associations were examined by multiple linear regression, testing for influence of genotype on neuroimaging. Markers in DYX2 genes KIAA0319 and FAM65B were associated with cortical thickness in the left orbitofrontal region and global fractional anisotropy, respectively. KIAA0319 and ACOT13 were suggestively associated with overall fractional anisotropy and left pars opercularis cortical thickness, respectively. DYX3 markers showed suggestive associations with cortical thickness and volume measures in temporal regions. Notably, we did not replicate association of DYX3 markers with hippocampal measures. In summary, we performed a neuroimaging follow-up of reading-, language-, and IQ-associated DYX2 and DYX3 markers. DYX2 associations with cortical thickness may reflect variations in their role in neuronal migration. Furthermore, our findings complement gene expression and imaging studies implicating DYX3 markers in temporal regions. These studies offer insight into where and how DYX2 and DYX3 risk variants may influence neuroimaging traits. Future studies should further connect the pathways to risk variants associated with neuroimaging/neurocognitive outcomes.

  11. [ANATOMICAL PLATE COMBINED WITH CORTICAL BONE PLATE ALLOGRAFTS FOR TREATMENT OF COMMINUTED FRACTURES OF FEMORAL CONDYLES].

    Science.gov (United States)

    Guo, Zhimin; Gong, Xingxing; Li, Yanwei; Qiu, Xiaochun; Zhang, Meng; Shangguan, Tiancheng; Ao, Qingfang; Liu, Qiang

    2015-01-01

    To summarize the effectiveness of anatomical plate combined with cortical bone plate allografts in the treatment of comminuted fractures of the femoral condyles. Between January 2008 and December 2012, 18 patients with comminuted fractures of the femoral condyles were treated, including 13 males and 5 females with an average age of 45 years (range, 23-65 years). Fractures were caused by traffic accident in 11 cases, by falling from height in 4 cases, and by the other in 3 cases. The locations were the left side in 7 cases and the right side in 11 cases. Of 18 fractures, 12 were open fractures and 6 were closed fractures. The mean time from injury to operation was 6 days (range, 4-15 days). The fixation was performed by anatomical plate combined with cortical bone plate allografts, and autograft bone or allogeneic bone grafting were used. Superficial local skin necrosis occurred in 1 case, and was cured after skin graft, and other incisions achieved primary healing. All patients were followed up 12-36 months (mean, 23 months). X-ray films showed that bone union was achieved within 3-12 months (5.6 months on average). No related complication occurred, such as fixation loosening, refracture, infection, or immunological rejection. According to Merchan et al. criteria for knee joint function evaluation, the results were excellent in 7 cases, good in 9 cases, fair in 1 case, and poor in 1 case at last follow-up; the excellent and good rate was 88.9%. Anatomical plate combined with cortical bone plate allograft fixation is a good method to treat comminuted fractures of the femoral condyles. This method can effectively achieve complete cortical bone on the inside of the femur as well as provide rigid fixation.

  12. The effect of alendronate treatment on cortical thickness of the proximal femur in postmenopausal women.

    Science.gov (United States)

    Mobini, Maryam; Dehghan, Leyla; Yosefi, Gholamali; Mohammadpour, Alireza; Abdi, Rohollah

    2016-01-01

    Bisphosphonates (BPs) are used extensively for managing the osteoporosis. There are some controversies on atypical fractures of femur that associated with increase in cortical thickness (CT) and BPs' use. In this study, the effects of alendronate consumption were studied on femoral CT as a predictor for atypical fracture. Forty nine post-menopausal women aged 50-70 years with osteopenia-osteoporosis who were treated with alendronate 70 mg/week for at least one year were compared to 49 controls for CT in subtrochanteric region of femur by hip dual-energy X-ray absorptiometry (DXA) scans and hip Xray. CT and its ratio were measured at 3.5 and 4.0 cm below the tip of the greater trochanter (GT) and 0.5 cm below lesser trochanter (LT) in DXA and at 9.5 and 10.5 cm of GT and 1 cm of LT in Xray. In this study, 98 women participated whose mean age and age at menopause were 60 (17±5.6) and 49 (40±2.7) years, respectively. Duration of BP consumption in alendronate group was 1.76±1.38 (1-10) years. No difference was seen in the mean of CT and its ratio between the alendronate and control groups in BMD scan or X-ray. The best correlation between two imaging modalities was in cortical ratio in 3.5 cm of GT in BMD scan and 9.5 cm of GT in X-ray. Alendronate treatment did not appear to increase femoral CT throughout the detection limits of BMD scan or X-ray.

  13. Cortical thickness in adolescent marijuana and alcohol users: A three-year prospective study from adolescence to young adulthood

    Directory of Open Access Journals (Sweden)

    Joanna Jacobus

    2015-12-01

    Full Text Available Studies suggest marijuana impacts gray and white matter neural tissue development, however few prospective studies have determined the relationship between cortical thickness and cannabis use spanning adolescence to young adulthood. This study aimed to understand how heavy marijuana use influences cortical thickness trajectories across adolescence. Subjects were adolescents with heavy marijuana use and concomitant alcohol use (MJ + ALC, n = 30 and controls (CON, n = 38 with limited substance use histories. Participants underwent magnetic resonance imaging and comprehensive substance use assessment at three independent time points. Repeated measures analysis of covariance was used to look at main effects of group, time, and Group × Time interactions on cortical thickness. MJ + ALC showed thicker cortical estimates across the brain (23 regions, particularly in frontal and parietal lobes (ps < .05. More cumulative marijuana use was associated with increased thickness estimates by 3-year follow-up (ps < .05. Heavy marijuana use during adolescence and into young adulthood may be associated with altered neural tissue development and interference with neuromaturation that can have neurobehavioral consequences. Continued follow-up of adolescent marijuana users will help understand ongoing neural changes that are associated with development of problematic use into adulthood, as well as potential for neural recovery with cessation of use.

  14. A Preliminary Study of the Influence of Age of Onset and Childhood Trauma on Cortical Thickness in Major Depressive Disorder

    Directory of Open Access Journals (Sweden)

    Natalia Jaworska

    2014-01-01

    Full Text Available Background. Major depressive disorder (MDD neural underpinnings may differ based on onset age and childhood trauma. We assessed cortical thickness in patients who differed in age of MDD onset and examined trauma history influence. Methods. Adults with MDD (N=36 and controls (HC; N=18 underwent magnetic resonance imaging. Twenty patients had MDD onset 25 years of age (adult onset. The MDD group was also subdivided into those with (N=12 and without (N=19 physical and/or sexual abuse as assessed by the Childhood Trauma Questionnaire (CTQ. Cortical thickness was analyzed with FreeSurfer software. Results. Thicker frontal pole and a tendency for thinner transverse temporal cortices existed in MDD. The former was driven by the pediatric onset group and abuse history (independently, particularly in the right frontal pole. Inverse correlations existed between CTQ scores and frontal pole cortex thickness. A similar inverse relation existed with left inferior and right superior parietal cortex thickness. The superior temporal cortex tended to be thinner in pediatric versus adult onset groups with childhood abuse. Conclusions. This preliminary work suggests neural differences between pediatric and adult MDD onset. Trauma history also contributes to cytoarchitectural modulation. Thickened frontal pole cortices as a compensatory mechanism in MDD warrant evaluation.

  15. Machining characteristics of the haversian and plexiform components of bovine cortical bone.

    Science.gov (United States)

    Conward, Michael; Samuel, Johnson

    2016-07-01

    This paper investigates the characteristic differences observed while machining the haversian and plexiform components of a bovine cortical femoral bone. To this end micro-milling slotting experiments are performed on both the components by varying both the cutting velocity and the feed-per-tooth values. The scale of machining is chosen specifically to ensure sensitivity to the microstructural variations in the bone. The material properties of the microstructural components and their size-scale relative to the feed-per-tooth values are seen to dictate the failure mechanisms encountered during machining. The cutting force, surface roughness, and tool wear are all uniquely affected by the plexiform and haversian components of the cortical bone. In general, plexiform bone requires a higher cutting force than the haversian bone. While a higher cutting velocity can lower the surface roughness of haversian bone, it typically results in the most surface damage. The cutting force and surface roughness values for both the components show strain rate sensitivity. The tool wear is seen to be the highest while cutting parallel to the lamellar structures seen in the plexiform bone.

  16. The micro-damage process zone during transverse cortical bone fracture: No ears at crack growth initiation.

    Science.gov (United States)

    Willett, Thomas; Josey, David; Lu, Rick Xing Ze; Minhas, Gagan; Montesano, John

    2017-10-01

    Apply high-resolution benchtop micro-computed tomography (micro-CT) to gain greater understanding and knowledge of the formation of the micro-damage process zone formed during traverse fracture of cortical bone. Bovine cortical bone was cut into single edge notch (bending) fracture testing specimens with the crack on the transverse plane and oriented to grow in the circumferential direction. We used a multi-specimen technique and deformed the specimens to various individual secant modulus loss levels (P-values) up to and including maximum load (Pmax). Next, the specimens were infiltrated with a BaSO4 precipitation stain and scanned at 3.57-μm isotropic voxel size using a benchtop high resolution-micro-CT. Measurements of the micro-damage process zone volume, width and height were made. These were compared with the simple Irwin's process zone model and with finite element models. Electron and confocal microscopy confirmed the formation of BaSO4 precipitate in micro-cracks and other porosity, and an interesting novel mechanism similar to tunneling. Measurable micro-damage was detected at low P values and the volume of the process zone increased according to a second order polynomial trend. Both width and height grew linearly up to Pmax, at which point the process zone cross-section (perpendicular to the plane of the crack) was almost circular on average with a radius of approximately 550µm (approximately one quarter of the unbroken ligament thickness) and corresponding to the shape expected for a biological composite under plane stress conditions. This study reports details of the micro-damage fracture process zone previously unreported for cortical bone. High-resolution micro-CT enables 3D visualization and measurement of the process zone and confirmation that the crack front edge and process zone are affected by microstructure. It is clear that the process zone for the specimens studied grows to be meaningfully large, confirming the need for the J

  17. MRI of the temporo-mandibular joint: which sequence is best suited to assess the cortical bone of the mandibular condyle? A cadaveric study using micro-CT as the standard of reference

    Energy Technology Data Exchange (ETDEWEB)

    Karlo, Christoph A. [University Hospital Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); University Children' s Hospital Zurich, Department of Diagnostic Imaging, Zurich (Switzerland); Patcas, Raphael; Signorelli, Luca; Mueller, Lukas [University of Zurich, Clinic for Orthodontics and Pediatric Dentistry, Center of Dental Medicine, Zurich (Switzerland); Kau, Thomas; Watzal, Helmut; Kellenberger, Christian J. [University Children' s Hospital Zurich, Department of Diagnostic Imaging, Zurich (Switzerland); Ullrich, Oliver [University of Zurich, Institute of Anatomy, Faculty of Medicine, Zurich (Switzerland); Luder, Hans-Ulrich [University of Zurich, Section of Orofacial Structures and Development, Center of Dental Medicine, Zurich (Switzerland)

    2012-07-15

    To determine the best suited sagittal MRI sequence out of a standard temporo-mandibular joint (TMJ) imaging protocol for the assessment of the cortical bone of the mandibular condyles of cadaveric specimens using micro-CT as the standard of reference. Sixteen TMJs in 8 human cadaveric heads (mean age, 81 years) were examined by MRI. Upon all sagittal sequences, two observers measured the cortical bone thickness (CBT) of the anterior, superior and posterior portions of the mandibular condyles (i.e. objective analysis), and assessed for the presence of cortical bone thinning, erosions or surface irregularities as well as subcortical bone cysts and anterior osteophytes (i.e. subjective analysis). Micro-CT of the condyles was performed to serve as the standard of reference for statistical analysis. Inter-observer agreements for objective (r = 0.83-0.99, P < 0.01) and subjective ({kappa} = 0.67-0.88) analyses were very good. Mean CBT measurements were most accurate, and cortical bone thinning, erosions, surface irregularities and subcortical bone cysts were best depicted on the 3D fast spoiled gradient echo recalled sequence (3D FSPGR). The most reliable MRI sequence to assess the cortical bone of the mandibular condyles on sagittal imaging planes is the 3D FSPGR sequence. (orig.)

  18. TYMPANOPLASTY WITH SEPTAL CARTILAGE AND CORTICAL MASTOID BONE IN CHOLESTEATOMA PATIENTS

    Directory of Open Access Journals (Sweden)

    Biram Singh

    2015-12-01

    Full Text Available OBJECTIVE This study was conducted to find out the ideal graft between septal cartilage and cortical mastoid bone in Farrior’s type 3 tympanoplasty in cholesteatoma patients in terms of hearing improvement, graft status and recurrence rate of the disease after canal wall down mastoidectomy. METHODS This randomized controlled trial was conducted in a tertiary care centre and the procedure and data collections were carried out for one and a half calendar year with effect from September 2007 and each case was followed up for 6 months. The data were entered and calculated statistically using SPSS16 for windows. RESULTS The study shows significant hearing improvement in both the groups. The tympanoplasty type 3 with cortical mastoid bone had air bone gap less than 20dB in 40% of patients. In septal cartilage, tympanoplasty group air bone gap less than 20dB was observed in 36.4%. Retraction of graft developed in 1(2.4% out of 20 patients among cortical mastoid bone tympanoplasty group. Among 22 patients of septal cartilage tympanoplasty type 3, 2(4.8% patients had cartilage resorption and 3(7.1% had graft displacement. Of the total 42 patients, 2(4.8% developed recurrence of the disease. CONCLUSION Cholesteatoma management is controversial. Canal wall down mastoidectomy can reduce the recurrence of disease. The cortical mastoid bone and septal cartilage grafts can provide hearing improvement after tympanoplasty type 3. There is no significant difference in hearing improvement between the two grafts.

  19. The effect of high energy shock waves focused on cortical bone: an in vitro study.

    Science.gov (United States)

    Kaulesar Sukul, D M; Johannes, E J; Pierik, E G; van Eijck, G J; Kristelijn, M J

    1993-01-01

    Extracorporeal shock wave lithotripsy has become an accepted alternative for the management of nephrolithiasis and cholelithiasis. Direct impact of shock waves cause tear and shear forces at transition sites between tissues with divergent acoustic impedances leading to stone fragmentation. The aim of this study was to determine whether shock waves can cause cortical bone damage at all and, if so, what the relationship is, if any, between the energy density of the shock waves, the number of shock waves applied, and the resulting cortical bone damage. With the Siemens Lithostar Plus with overhead module, electromagnetic shock waves, generated under water with energy densities of 0.23, 0.33, 0.42, or 0.54 mJ/mm2, corresponding with power settings 2, 4, 6, and 8, were applied to bone specimens, i.e., of rabbit femurs and tibiae. Prior to exposure to the shock waves, the bones were mounted on a specially constructed perspex holder which could be placed in a water-filled test basin with an elastic membrane in the front through which the shock waves propagate without loss of energy. This setup made it possible not only to induce complete fractures, but also to detect the existence of a linear relationship with a Spearman rank correlation coefficient of -0.72 (P < or = 0.01) between the energy level of the shock waves and the severity of the cortical bone defects. The latter findings are especially of great importance because this means that the process can be controlled and that the cortical effects will be predictable and reproducible. This study should be considered a preliminary test concerning the effects of high energy shock wave on bone.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Time Related Changes of Mineral and Collagen and Their Roles in Cortical Bone Mechanics of Ovariectomized Rabbits.

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    Xin-Xin Wen

    Full Text Available As cortical bone has a hierarchical structure, the macroscopic bone strength may be affected by the alterations of mineral crystal and collagen, which are main components of cortical bone. Limited studies focused on the time related alterations of these two components in osteoporosis, and their contributions to bone mechanics at tissue level and whole-bone level. Therefore, the purpose of this study was to elucidate the time related changes of mineral and collagen in cortical bone of ovariectomized (OVX rabbits, and to relate these changes to cortical bone nanomechanics and macromechanics. 40 Rabbits (7-month-old were randomly allocated into two groups (OVX and sham. OVX group received bilateral ovariectomy operation. Sham group received sham-OVX operation. Cortical bone quality of five rabbits in each group were assessed by DXA, μCT, nanoindentation, Fourier transform infrared (FTIR spectroscopy and biomechanical tests (3-point bending of femoral midshaft at pre-OVX, 4, 6, and 8 weeks after OVX. As time increased from pre-OVX to 8 weeks, the mineral to matrix ratio decreased with time, while both collagen crosslink ratio and crystallinity increased with time in OVX group. Elastic modulus and hardness measured by nanoindentation, whole-bone strength measured by biomechanical tests all decreased in OVX group with time. Bone material properties measured by FTIR correlated well with nano or whole-bone level mechanics. However, bone mineral density (BMD, structure, tissue-level and whole-bone mechanical properties did not change with age in sham group. Our study demonstrated that OVX could affect the tissue-level mechanics and bone strength of cortical bone. And this influence was attributed to the time related alterations of mineral and collagen properties, which may help us to design earlier interventions and more effective treatment strategies on osteoporosis.

  1. Safe Harvesting of Outer Table Parietal Bone Grafts Using an Oscillating Saw and a Bone Scraper : A Refinement of Technique for Harvesting Cortical and "Cancellous"-Like Calvarial Bone

    NARCIS (Netherlands)

    Schortinghuis, Jurjen; Putters, Thomas F.; Raghoebar, Gerry M.

    2012-01-01

    Calvarial bone is a readily available source of bone for preimplantation augmentation procedures of the alveolar process. However, the calvaria consist mostly of cortical bone, and cancellous bone of the diploic space is scarce. A bone scraper (Safescraper Twist; META, Reggio Emilia, Italy) was used

  2. Histological analysis of the alterations on cortical bone channels network after radiotherapy: A rabbit study.

    Science.gov (United States)

    Rabelo, Gustavo Davi; Beletti, Marcelo Emílio; Dechichi, Paula

    2010-10-01

    The aim of this study was to evaluate the effects of radiotherapy in cortical bone channels network. Fourteen rabbits were divided in two groups and test group received single dose of 15 Gy cobalt-60 radiation in tibia, bilaterally. The animals were sacrificed and a segment of tibia was removed and histologically processed. Histological images were taken and had their bone channels segmented and called regions of interest (ROI). Images were analyzed through developed algorithms using the SCILAB mathematical environment, getting percentage of bone matrix, ROI areas, ROI perimeters, their standard deviations and Lacunarity. The osteocytes and empty lacunae were also counted. Data were evaluated using Kolmogorov-Smirnov, Mann Whitney, and Student's t test (P lacunarity were found between groups. In conclusion, the radiotherapy causes reduction of bone matrix and modifies the morphology of bone channels network. © 2010 Wiley-Liss, Inc.

  3. Laminar thickness alterations in the fronto-parietal cortical mantle of patients with attention-deficit/hyperactivity disorder.

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    Elseline Hoekzema

    Full Text Available Although Attention-Deficit/Hyperactivity Disorder (ADHD was initially regarded as a disorder exclusive to childhood, nowadays its prevalence in adulthood is well established. The development of novel techniques for quantifying the thickness of the cerebral mantle allows the further exploration of the neuroanatomical profiles underlying the child and adult form of the disorder. To examine the cortical mantle in children and adults with ADHD, we applied a vertex-wise analysis of cortical thickness to anatomical brain MRI scans acquired from children with (n = 43 and without ADHD (n = 41, as well as a group of adult neurotypical individuals (n = 31, adult patients with a history of stimulant treatment (n = 31 and medication-naïve adults with ADHD (n = 24. We observed several clusters of reduced laminar cortical thickness in ADHD patients in comparison to neurotypical individuals. These differences were primarily located in the dorsal attention network, including the bilateral inferior and superior parietal cortex and a section of the frontal cortex (centered on the superior frontal and precentral gyrus bilaterally. Further laminar thickness deficits were observed in the bilateral orbitofrontal cortex and medial occipital cortex. The deficits in the cortical surface were especially pronounced in the child sample, while adult patients showed a more typical laminar thickness across the cerebral mantle. These findings show that the neuroanatomical profile of ADHD, especially the childhood form of the disorder, involves robust alterations in the cortical mantle, which are most prominent in brain regions subserving attentional processing.

  4. Laminar Thickness Alterations in the Fronto-Parietal Cortical Mantle of Patients with Attention-Deficit/Hyperactivity Disorder

    Science.gov (United States)

    Ramos-Quiroga, J. Antoni; Fernández, Vanesa Richarte; Picado, Marisol; Bosch, Rosa; Soliva, Juan Carlos; Rovira, Mariana; Vives, Yolanda; Bulbena, Antonio; Tobeña, Adolf; Casas, Miguel; Vilarroya, Oscar

    2012-01-01

    Although Attention-Deficit/Hyperactivity Disorder (ADHD) was initially regarded as a disorder exclusive to childhood, nowadays its prevalence in adulthood is well established. The development of novel techniques for quantifying the thickness of the cerebral mantle allows the further exploration of the neuroanatomical profiles underlying the child and adult form of the disorder. To examine the cortical mantle in children and adults with ADHD, we applied a vertex-wise analysis of cortical thickness to anatomical brain MRI scans acquired from children with (n = 43) and without ADHD (n = 41), as well as a group of adult neurotypical individuals (n = 31), adult patients with a history of stimulant treatment (n = 31) and medication-naïve adults with ADHD (n = 24). We observed several clusters of reduced laminar cortical thickness in ADHD patients in comparison to neurotypical individuals. These differences were primarily located in the dorsal attention network, including the bilateral inferior and superior parietal cortex and a section of the frontal cortex (centered on the superior frontal and precentral gyrus bilaterally). Further laminar thickness deficits were observed in the bilateral orbitofrontal cortex and medial occipital cortex. The deficits in the cortical surface were especially pronounced in the child sample, while adult patients showed a more typical laminar thickness across the cerebral mantle. These findings show that the neuroanatomical profile of ADHD, especially the childhood form of the disorder, involves robust alterations in the cortical mantle, which are most prominent in brain regions subserving attentional processing. PMID:23239964

  5. SKA2 methylation is associated with decreased prefrontal cortical thickness and greater PTSD severity among trauma-exposed veterans.

    Science.gov (United States)

    Sadeh, N; Spielberg, J M; Logue, M W; Wolf, E J; Smith, A K; Lusk, J; Hayes, J P; Sperbeck, E; Milberg, W P; McGlinchey, R E; Salat, D H; Carter, W C; Stone, A; Schichman, S A; Humphries, D E; Miller, M W

    2016-03-01

    Methylation of the SKA2 (spindle and kinetochore-associated complex subunit 2) gene has recently been identified as a promising biomarker of suicide risk. Based on this finding, we examined associations between SKA2 methylation, cortical thickness and psychiatric phenotypes linked to suicide in trauma-exposed veterans. About 200 trauma-exposed white non-Hispanic veterans of the recent conflicts in Iraq and Afghanistan (91% male) underwent clinical assessment and had blood drawn for genotyping and methylation analysis. Of all, 145 participants also had neuroimaging data available. Based on previous research, we examined DNA methylation at the cytosine-guanine locus cg13989295 as well as DNA methylation adjusted for genotype at the methylation-associated single nucleotide polymorphism (rs7208505) in relationship to whole-brain cortical thickness, posttraumatic stress disorder symptoms (PTSD) and depression symptoms. Whole-brain vertex-wise analyses identified three clusters in prefrontal cortex that were associated with genotype-adjusted SKA2 DNA methylation (methylation(adj)). Specifically, DNA methylation(adj) was associated with bilateral reductions of cortical thickness in frontal pole and superior frontal gyrus, and similar effects were found in the right orbitofrontal cortex and right inferior frontal gyrus. PTSD symptom severity was positively correlated with SKA2 DNA methylation(adj) and negatively correlated with cortical thickness in these regions. Mediation analyses showed a significant indirect effect of PTSD on cortical thickness via SKA2 methylation status. Results suggest that DNA methylation(adj) of SKA2 in blood indexes stress-related psychiatric phenotypes and neurobiology, pointing to its potential value as a biomarker of stress exposure and susceptibility.

  6. Mesenchymal stem cells from cortical bone demonstrate increased clonal incidence, potency, and developmental capacity compared to their bone marrow–derived counterparts

    Directory of Open Access Journals (Sweden)

    Daniel Blashki

    2016-08-01

    Full Text Available In this study, we show that matrix dense cortical bone is the more potent compartment of bone than bone marrow as a stromal source for mesenchymal stem cells as isolated from adult rats. Lineage-depleted cortical bone-mesenchymal stem cells demonstrated >150-fold enrichment of colony forming unit–fibroblasts per cell incidence. compared to lineage-depleted bone marrow-mesenchymal stem cells, corresponding to a 70-fold increase in absolute recovered colony forming unit–fibroblasts. The composite phenotype Lin−/CD45−/CD31−/VLA-1+/Thy-1+ enriched for clonogenic mesenchymal stem cells solely from cortical bone–derived cells from which 70% of clones spontaneously differentiated into all lineages of bone, cartilage, and adipose. Both populations generated vascularized bone tissue within subcutaneous implanted collagen scaffolds; however, cortical bone–derived cells formed significantly more osteoid than bone marrow counterparts, quantified by histology. The data demonstrate that our isolation protocol identifies and validates mesenchymal stem cells with superior clonal, proliferative, and developmental potential from cortical bone compared to the bone marrow niche although marrow persists as the typical source for mesenchymal stem cells both in the literature and current pre-clinical therapies.

  7. Mesenchymal stem cells from cortical bone demonstrate increased clonal incidence, potency, and developmental capacity compared to their bone marrow–derived counterparts

    Science.gov (United States)

    Blashki, Daniel; Murphy, Matthew B; Ferrari, Mauro; Simmons, Paul J; Tasciotti, Ennio

    2016-01-01

    In this study, we show that matrix dense cortical bone is the more potent compartment of bone than bone marrow as a stromal source for mesenchymal stem cells as isolated from adult rats. Lineage-depleted cortical bone-mesenchymal stem cells demonstrated >150-fold enrichment of colony forming unit–fibroblasts per cell incidence. compared to lineage-depleted bone marrow-mesenchymal stem cells, corresponding to a 70-fold increase in absolute recovered colony forming unit–fibroblasts. The composite phenotype Lin−/CD45−/CD31−/VLA-1+/Thy-1+ enriched for clonogenic mesenchymal stem cells solely from cortical bone–derived cells from which 70% of clones spontaneously differentiated into all lineages of bone, cartilage, and adipose. Both populations generated vascularized bone tissue within subcutaneous implanted collagen scaffolds; however, cortical bone–derived cells formed significantly more osteoid than bone marrow counterparts, quantified by histology. The data demonstrate that our isolation protocol identifies and validates mesenchymal stem cells with superior clonal, proliferative, and developmental potential from cortical bone compared to the bone marrow niche although marrow persists as the typical source for mesenchymal stem cells both in the literature and current pre-clinical therapies. PMID:27579159

  8. Effects of estrogen with micronized progesterone on cortical and trabecular bone mass and microstructure in recently postmenopausal women.

    Science.gov (United States)

    Farr, Joshua N; Khosla, Sundeep; Miyabara, Yuko; Miller, Virginia M; Kearns, Ann E

    2013-02-01

    In women, cortical bone mass decreases significantly at menopause. By contrast, loss of trabecular bone begins in the third decade and accelerates after menopause. The aim of the study was to investigate the effects of estrogen on cortical and trabecular bone. The Kronos Early Estrogen Prevention Study is a double-blind, randomized, placebo-controlled trial of menopausal hormone treatment (MHT) in women, enrolled within 6-36 months of their final menstrual period. The study was conducted at the Mayo Clinic, Rochester, Minnesota. Subjects were treated with placebo (n = 31), or .45 mg/d conjugated equine estrogens (n = 20), or transdermal 50 μg/d 17β-estradiol (n = 25) with pulsed micronized progesterone. Cortical and trabecular microarchitecture at the distal radius was assessed by high-resolution peripheral quantitative computed tomography. At the distal radius, cortical volumetric bone mineral density (vBMD) decreased, and cortical porosity increased in the placebo group; MHT prevented these changes. By contrast, MHT did not prevent decreases in trabecular microarchitecture at the radius. However, MHT prevented decreases in trabecular vBMD at the thoracic spine (assessed in a subset of subjects; n = 51). These results indicate that MHT prevents deterioration in radial cortical vBMD and porosity in recently menopausal women. The maintenance of cortical bone in response to estrogen likely has important clinical implications because cortical bone morphology plays an important role in bone strength. However, effects of MHT on trabecular bone at the radius differ from those at the thoracic spine. Underlying mechanisms for these site-specific effects of MHT on cortical vs trabecular bone require further investigation.

  9. A comparison of brain volume and cortical thickness in excoriation (skin picking) disorder and trichotillomania (hair pulling disorder) in women.

    Science.gov (United States)

    Roos, Annerine; Grant, Jon E; Fouche, Jean-Paul; Stein, Dan J; Lochner, Christine

    2015-02-15

    Skin picking disorder (SPD) and trichotillomania (hair pulling disorder, or HPD) significantly overlap in terms of clinical features. However, few studies have directly compared structural brain data in these disorders. The aim of this study was to compare volumes of brain structures and cortical thickness in patients with SPD and HPD, and determine involvement of fronto-striatal pathways. Seventeen female SPD, 17 HPD and 15 healthy age-matched controls underwent clinical assessment and structural MRI imaging. Group differences were determined in brain volume and cortical thickness, controlling for illness severity. Participants with SPD had greater volume of the ventral striatum bilaterally; and reduced cortical thickness in right hemisphere frontal areas, and greater thickness of the cuneus bilaterally compared to HPD and control participants. HPD participants demonstrated reduced thickness of the right parahippocampal gyrus compared to SPD and control participants. The findings here are partially consistent with previous structural work in SPD, and suggest some differences in the neurobiology of SPD and HPD. The more extensive involvement of the ventral striatum in SPD may suggest greater involvement of the reward system, while the more extensive involvement of the parahippocampal gyrus in HPD may be consistent with the dissociative symptoms often seen in these patients.

  10. Age-related changes in collagen properties and mineralization in cancellous and cortical bone in the porcine mandibular condyle.

    Science.gov (United States)

    Willems, Nop M B K; Langenbach, Geerling E J; Everts, Vincent; Mulder, Lars; Grünheid, Thorsten; Bank, Ruud A; Zentner, Andrej; van Eijden, Theo M G J

    2010-04-01

    Collagen is an important constituent of bone, and it has been suggested that changes in collagen and mineral properties of bone are interrelated during growth. The aim of this study was to quantify age-related changes in collagen properties and the degree of mineralization of bone (DMB). The DMB in cancellous and cortical bone samples from the mandibular condyle of 35 female pigs aged 0-100 weeks was determined using micro-computed tomography. Subsequently, the amount of collagen and the number of pentosidine (Pen), hydroxylysylpyridinoline (HP), and lysylpyridinoline (LP) cross-links were quantified by means of high-performance liquid chromatography. The amount of collagen increased with age in cancellous bone but remained unchanged in cortical bone. The number of Pen and LP cross-links decreased in both bone types. In contrast, the number of HP cross-links decreased only in cancellous bone. The sum of the number of HP and LP cross-links decreased with age in cancellous bone only. The DMB increased in cancellous and cortical bone. It was concluded that the largest changes in the number of mature collagen cross-links and the mineralization in porcine cancellous and cortical bone take place before the age of 40 weeks. The low number of mature cross-links after this age suggests that the bone turnover rate continues to be high and thereby prevents the development of mature cross-links.

  11. The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone

    DEFF Research Database (Denmark)

    Ding, Ming; Danielsen, Carl Christian; Overgaard, Søren

    2011-01-01

    of 3 months without treatment. Group 3 was left untreated and served as controls. All sheep received a restricted diet with low calcium and phosphorus. At sacrifice, cortical bone samples from the femur midshaft of each sheep were harvested, micro-CT scanned and subjected to three-point bending...... the groups, while there was a trend towards decreasing bending mechanical properties in the glucocorticoid-2 group. In conclusion, 7 months of glucocorticoid treatment with malnutrition had a significant impact on the cortical microarchitecture of the sheep femur midshaft. These observed changes occurred 3...

  12. Cortical thickness of superior frontal cortex predicts impulsiveness and perceptual reasoning in adolescence.

    Science.gov (United States)

    Schilling, C; Kühn, S; Paus, T; Romanowski, A; Banaschewski, T; Barbot, A; Barker, G J; Brühl, R; Büchel, C; Conrod, P J; Dalley, J W; Flor, H; Ittermann, B; Ivanov, N; Mann, K; Martinot, J-L; Nees, F; Rietschel, M; Robbins, T W; Smolka, M N; Ströhle, A; Kathmann, N; Garavan, H; Heinz, A; Schumann, G; Gallinat, J

    2013-05-01

    Impulsiveness is a pivotal personality trait representing a core domain in all major personality inventories. Recently, impulsiveness has been identified as an important modulator of cognitive processing, particularly in tasks that require the processing of large amounts of information. Although brain imaging studies have implicated the prefrontal cortex to be a common underlying representation of impulsiveness and related cognitive functioning, to date a fine-grain and detailed morphometric analysis has not been carried out. On the basis of ahigh-resolution magnetic resonance scans acquired in 1620 healthy adolescents (IMAGEN), the individual cortical thickness (CT) was estimated. Correlations between Cloninger's impulsiveness and CT were studied in an entire cortex analysis. The cluster identified was tested for associations with performance in perceptual reasoning tasks of the Wechsler Intelligence Scale for Children (WISC IV). We observed a significant inverse correlation between trait impulsiveness and CT of the left superior frontal cortex (SFC; Monte Carlo Simulation P<0.01). CT within this cluster correlated with perceptual reasoning scores (Bonferroni corrected) of the WISC IV. On the basis of a large sample of adolescents, we identified an extended area in the SFC as a correlate of impulsiveness, which appears to be in line with the trait character of this prominent personality facet. The association of SFC thickness with perceptual reasoning argues for a common neurobiological basis of personality and specific cognitive domains comprising attention, spatial reasoning and response selection. The results may facilitate the understanding of the role of impulsiveness in several psychiatric disorders associated with prefrontal dysfunctions and cognitive deficits.

  13. In situ observation of fracture behavior of canine cortical bone under bending

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Zilan X. [Department of Orthopaedics, Medical University of South Carolina, 96 Jonathan Lucas Street Suite 708 MSC 622, Charleston, SC 29425 (United States); Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); Xu, Zhi-Hui [Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); An, Yuehuei H. [Department of Orthopaedics, Medical University of South Carolina, 96 Jonathan Lucas Street Suite 708 MSC 622, Charleston, SC 29425 (United States); Department of Orthopaedic Surgery, Southside Hospital, North Shore-LIJ Health System, 217 East Main Street, Bay Shore, NY 11706 (United States); Li, Xiaodong, E-mail: xl3p@virginia.edu [Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer' s Way, Charlottesville, VA 22904 (United States)

    2016-05-01

    Cortical bone provides many important body functions and maintains the rigidness and elasticity of bone. A common failure mode for bone structure is fracture under a bending force. In the current study, the fracture behavior of canine cortical bone under three-point bending was observed in situ using an atomic force microscope (AFM), a scanning electron microscope (SEM), and an optical microscope to examine the fracture process in detail. Nanoindentation was carried out to determine the elastic modulus and hardness of different building blocks of the canine cortical bone. The results have shown that the special structure of Haversian systems has significant effects on directing crack propagation. Although Haversian systems contain previously believed weak points, and micro-cracks initiate within Haversian systems, our findings have demonstrated that macro-cracks typically form around the boundaries of Haversian systems, i.e. the cement lines. Micro-cracks that developed inside Haversian systems have the functions of absorbing and dissipating energy and slow down on expanding when interstitial tissue cannot hold any more pressure, then plastic deformation and fracture occur. - Highlights: • Macro- and micro-cracks occur in unique patterns in the bone fracturing process under a bending force. • Early developed micro-cracks inside Haversian systems absorb and dissipate energy in order to delay fracture initiation. • The mechanical properties of Haverisan systems and its surrounding structures influence the developments of macro- and micro-crack formation. • Previously believed weak spots in the bone matrix are not necessarily the origins of fracture development.

  14. Spaceflight-relevant types of ionizing radiation and cortical bone: Potential LET effect?

    Science.gov (United States)

    Lloyd, Shane A.J.; Bandstra, Eric R.; Travis, Neil D.; Nelson, Gregory A.; Bourland, J. Daniel; Pecaut, Michael J.; Gridley, Daila S.; Willey, Jeffrey S.; Bateman, Ted A.

    2008-01-01

    Extended exposure to microgravity conditions results in significant bone loss. Coupled with radiation exposure, this phenomenon may place astronauts at a greater risk for mission-critical fractures. In a previous study, we identified a profound and prolonged loss of trabecular bone (29−39%) in mice following exposure to an acute, 2 Gy dose of radiation simulating both solar and cosmic sources. However, because skeletal strength depends on trabecular and cortical bone, accurate assessment of strength requires analysis of both bone compartments. The objective of the present study was to examine various properties of cortical bone in mice following exposure to multiple types of spaceflight-relevant radiation. Nine-week old, female C57BL/6 mice were sacrificed 110 days after exposure to a single, whole body, 2 Gy dose of gamma, proton, carbon, or iron radiation. Femora were evaluated with biomechanical testing, microcomputed tomography, quantitative histomorphometry, percent mineral content, and micro-hardness analysis. Compared to non-irradiated controls, there were significant differences compared to carbon or iron radiation for only fracture force, medullary area and mineral content. A greater differential effect based on linear energy transfer (LET) level may be present: high-LET (carbon or iron) particle irradiation was associated with a decline in structural properties (maximum force, fracture force, medullary area, and cortical porosity) and mineral composition compared to low-LET radiation (gamma and proton). Bone loss following irradiation appears to be largely specific to trabecular bone and may indicate unique biological microenvironments and microdosimetry conditions. However, the limited time points examined and non-haversian skeletal structure of the mice employed highlight the need for further investigation. PMID:19122806

  15. Multiple bases of human intelligence revealed by cortical thickness and neural activation.

    Science.gov (United States)

    Choi, Yu Yong; Shamosh, Noah A; Cho, Sun Hee; DeYoung, Colin G; Lee, Min Joo; Lee, Jong-Min; Kim, Sun I; Cho, Zang-Hee; Kim, Kyungjin; Gray, Jeremy R; Lee, Kun Ho

    2008-10-08

    We hypothesized that individual differences in intelligence (Spearman's g) are supported by multiple brain regions, and in particular that fluid (gF) and crystallized (gC) components of intelligence are related to brain function and structure with a distinct profile of association across brain regions. In 225 healthy young adults scanned with structural and functional magnetic resonance imaging sequences, regions of interest (ROIs) were defined on the basis of a correlation between g and either brain structure or brain function. In these ROIs, gC was more strongly related to structure (cortical thickness) than function, whereas gF was more strongly related to function (blood oxygenation level-dependent signal during reasoning) than structure. We further validated this finding by generating a neurometric prediction model of intelligence quotient (IQ) that explained 50% of variance in IQ in an independent sample. The data compel a nuanced view of the neurobiology of intelligence, providing the most persuasive evidence to date for theories emphasizing multiple distributed brain regions differing in function.

  16. Towards a Holistic Cortical Thickness Descriptor: Heat Kernel-Based Grey Matter Morphology Signatures.

    Science.gov (United States)

    Wang, Gang; Wang, Yalin

    2017-02-15

    In this paper, we propose a heat kernel based regional shape descriptor that may be capable of better exploiting volumetric morphological information than other available methods, thereby improving statistical power on brain magnetic resonance imaging (MRI) analysis. The mechanism of our analysis is driven by the graph spectrum and the heat kernel theory, to capture the volumetric geometry information in the constructed tetrahedral meshes. In order to capture profound brain grey matter shape changes, we first use the volumetric Laplace-Beltrami operator to determine the point pair correspondence between white-grey matter and CSF-grey matter boundary surfaces by computing the streamlines in a tetrahedral mesh. Secondly, we propose multi-scale grey matter morphology signatures to describe the transition probability by random walk between the point pairs, which reflects the inherent geometric characteristics. Thirdly, a point distribution model is applied to reduce the dimensionality of the grey matter morphology signatures and generate the internal structure features. With the sparse linear discriminant analysis, we select a concise morphology feature set with improved classification accuracies. In our experiments, the proposed work outperformed the cortical thickness features computed by FreeSurfer software in the classification of Alzheimer's disease and its prodromal stage, i.e., mild cognitive impairment, on publicly available data from the Alzheimer's Disease Neuroimaging Initiative. The multi-scale and physics based volumetric structure feature may bring stronger statistical power than some traditional methods for MRI-based grey matter morphology analysis.

  17. Cortical thickness in children receiving intensive therapy for idiopathic apraxia of speech.

    Science.gov (United States)

    Kadis, Darren S; Goshulak, Debra; Namasivayam, Aravind; Pukonen, Margit; Kroll, Robert; De Nil, Luc F; Pang, Elizabeth W; Lerch, Jason P

    2014-03-01

    Children with idiopathic apraxia experience difficulties planning the movements necessary for intelligible speech. There is increasing evidence that targeted early interventions, such as Prompts for Restructuring Oral Muscular Phonetic Targets (PROMPT), can be effective in treating these disorders. In this study, we investigate possible cortical thickness correlates of idiopathic apraxia of speech in childhood, and changes associated with participation in an 8-week block of PROMPT therapy. We found that children with idiopathic apraxia (n = 11), aged 3-6 years, had significantly thicker left supramarginal gyri than a group of typically-developing age-matched controls (n = 11), t(20) = 2.84, p ≤ 0.05. Over the course of therapy, the children with apraxia (n = 9) experienced significant thinning of the left posterior superior temporal gyrus (canonical Wernicke's area), t(8) = 2.42, p ≤ 0.05. This is the first study to demonstrate experience-dependent structural plasticity in children receiving therapy for speech sound disorders.

  18. Reduced cortical thickness and its association with social reactivity in children with autism spectrum disorder.

    Science.gov (United States)

    Richter, Julia; Henze, Romy; Vomstein, Kilian; Stieltjes, Bram; Parzer, Peter; Haffner, Johann; Brandeis, Daniel; Poustka, Luise

    2015-10-30

    Symptomatology and behavioral characteristics in autism spectrum disorders (ASD) have increasingly been linked to abnormalities in early brain growth patterns of affected children. Studies investigating specific components of gray matter structure, such as cortical thickness (CT), have produced conflicting results, and have rarely included additional measures of social impairment. In the present study, we applied a surface-based whole brain analysis to investigate CT in a sample of 36 pre-adolescent children [18 subjects with ASD (IQ mean: 111) and 18 healthy controls (IQ mean: 112.8), age range 6-12 years]. The CT analysis revealed widespread, but mostly left-hemispheric thinning in frontal, temporal, parietal and occipital brain areas related to the theory-of-mind network and the heteromodal association cortex. In an exploratory analysis, CT was observed to be differently associated with social impairment in children with ASD compared with typically developing children. The affected neuroanatomical regions are related to characteristic deficits in language, cognition and behavior that are often observed in the disorder. The relationship between social impairment and CT in children with ASD and controls seems to indicate aberrant developmental trajectories in ASD emerging early in life. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  19. Greater Cortical Thickness in Elderly Female Yoga Practitioners-A Cross-Sectional Study.

    Science.gov (United States)

    Afonso, Rui F; Balardin, Joana B; Lazar, Sara; Sato, João R; Igarashi, Nadja; Santaella, Danilo F; Lacerda, Shirley S; Amaro, Edson; Kozasa, Elisa H

    2017-01-01

    Yoga, a mind-body activity that requires attentional engagement, has been associated with positive changes in brain structure and function, especially in areas related to awareness, attention, executive functions and memory. Normal aging, on the other hand, has also been associated with structural and functional brain changes, but these generally involve decreased cognitive functions. The aim of this cross-sectional study was to compare brain cortical thickness (CT) in elderly yoga practitioners and a group of age-matched healthy non-practitioners. We tested 21 older women who had practiced hatha yoga for at least 8 years and 21 women naive to yoga, meditation or any mind-body interventions who were matched to the first group in age, years of formal education and physical activity level. A T1-weighted MPRAGE sequence was acquired for each participant. Yoga practitioners showed significantly greater CT in a left prefrontal lobe cluster, which included portions of the lateral middle frontal gyrus, anterior superior frontal gyrus and dorsal superior frontal gyrus. We found greater CT in the left prefrontal cortex of healthy elderly women who trained yoga for a minimum of 8 years compared with women in the control group.

  20. Greater Cortical Thickness in Elderly Female Yoga Practitioners—A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Rui F. Afonso

    2017-06-01

    Full Text Available Yoga, a mind-body activity that requires attentional engagement, has been associated with positive changes in brain structure and function, especially in areas related to awareness, attention, executive functions and memory. Normal aging, on the other hand, has also been associated with structural and functional brain changes, but these generally involve decreased cognitive functions. The aim of this cross-sectional study was to compare brain cortical thickness (CT in elderly yoga practitioners and a group of age-matched healthy non-practitioners. We tested 21 older women who had practiced hatha yoga for at least 8 years and 21 women naive to yoga, meditation or any mind-body interventions who were matched to the first group in age, years of formal education and physical activity level. A T1-weighted MPRAGE sequence was acquired for each participant. Yoga practitioners showed significantly greater CT in a left prefrontal lobe cluster, which included portions of the lateral middle frontal gyrus, anterior superior frontal gyrus and dorsal superior frontal gyrus. We found greater CT in the left prefrontal cortex of healthy elderly women who trained yoga for a minimum of 8 years compared with women in the control group.

  1. Cortical bone growth and maturational changes in dwarf rats induced by recombinant human growth hormone

    Science.gov (United States)

    Martinez, D. A.; Orth, M. W.; Carr, K. E.; Vanderby, R. Jr; Vailas, A. C.

    1996-01-01

    The growth hormone (GH)-deficient dwarf rat was used to investigate recombinant human (rh) GH-induced bone formation and to determine whether rhGH facilitates simultaneous increases in bone formation and bone maturation during rapid growth. Twenty dwarf rats, 37 days of age, were randomly assigned to dwarf plus rhGH (GH; n = 10) and dwarf plus vehicle (n = 10) groups. The GH group received 1.25 mg rhGH/kg body wt two times daily for 14 days. Biochemical, morphological, and X-ray diffraction measurements were performed on the femur middiaphysis. rhGH stimulated new bone growth in the GH group, as demonstrated by significant increases (P bone length (6%), middiaphyseal cross-sectional area (20%), and the amount of newly accreted bone collagen (28%) in the total pool of middiaphyseal bone collagen. Cortical bone density, mean hydroxyapatite crystal size, and the calcium and collagen contents (microgram/mm3) were significantly smaller in the GH group (P bone collagen maturation, and mean hydroxyapatite crystal size may be independently regulated during rapid growth.

  2. Cortical bone tissue resists fatigue fracture by deceleration and arrest of microcrack growth.

    Science.gov (United States)

    Akkus, O; Rimnac, C M

    2001-06-01

    Knowledge of kinetics of fatigue crack growth of microcracks is important so as to understand the dynamics of bone adaptation, remodeling, and the etiology of fatigue-based failures of cortical bone tissue. In this respect, theoretical models (Taylor, J. Biomech., 31 (1998) 587-592; Taylor and Prendergast, Proc. Instn. Mech. Engrs. Part H 211 (1997) 369-375) of microcrack growth in cortical bone have predicted a decreasing microcrack growth rate with increasing microcrack length. However, these predictions have not been observed directly. This study investigated microcrack growth and arrest through observations of surface microcracks during cyclic loading (R=0.1, 50-80MPa) of human femoral cortical bone (male, n=4, age range: 37-40yr) utilizing a video microscopy system. The change in crack length and orientation of eight surface microcracks were measured with the number of fatigue cycles from four specimens. At the applied cyclic stresses, the microcracks propagated and arrested in generally less than 10,000 cycles. The fatigue crack growth rate of all microcracks decreased with increasing crack length following initial identification, consistent with theoretical predictions. The growth rate of the microcracks was observed to be in the range of 5x10(-5) to 5x10(-7)mmcycle(-1). In addition, many of the microcracks were observed not to grow beyond 150 microm and a cyclic stress intensity factor of 0.5MNm(-3/2). The results of this study suggest that cortical bone tissue may resist fracture at the microscale by deceleration of fatigue crack growth and arrest of microcracks.

  3. Genome-wide association meta-analysis of cortical bone mineral density unravels allelic heterogeneity at the RANKL locus and potential pleiotropic effects on bone.

    Directory of Open Access Journals (Sweden)

    Lavinia Paternoster

    2010-11-01

    Full Text Available Previous genome-wide association (GWA studies have identified SNPs associated with areal bone mineral density (aBMD. However, this measure is influenced by several different skeletal parameters, such as periosteal expansion, cortical bone mineral density (BMD(C cortical thickness, trabecular number, and trabecular thickness, which may be under distinct biological and genetic control. We have carried out a GWA and replication study of BMD(C, as measured by peripheral quantitative computed tomography (pQCT, a more homogenous and valid measure of actual volumetric bone density. After initial GWA meta-analysis of two cohorts (ALSPAC n = 999, aged ∼15 years and GOOD n = 935, aged ∼19 years, we attempted to replicate the BMD(C associations that had p<1×10(-5 in an independent sample of ALSPAC children (n = 2803 and in a cohort of elderly men (MrOS Sweden, n = 1052. The rs1021188 SNP (near RANKL was associated with BMD(C in all cohorts (overall p = 2×10(-14, n = 5739. Each minor allele was associated with a decrease in BMD(C of ∼0.14SD. There was also evidence for an interaction between this variant and sex (p = 0.01, with a stronger effect in males than females (at age 15, males -6.77mg/cm(3 per C allele, p = 2×10(-6; females -2.79 mg/cm(3 per C allele, p = 0.004. Furthermore, in a preliminary analysis, the rs1021188 minor C allele was associated with higher circulating levels of sRANKL (p<0.005. We show this variant to be independent from the previously aBMD associated SNP (rs9594738 and possibly from a third variant in the same RANKL region, which demonstrates important allelic heterogeneity at this locus. Associations with skeletal parameters reflecting bone dimensions were either not found or were much less pronounced. This finding implicates RANKL as a locus containing variation associated with volumetric bone density and provides further insight into the mechanism by which the RANK/RANKL/OPG pathway

  4. Striatal phosphodiesterase 10A and medial prefrontal cortical thickness in patients with schizophrenia: a PET and MRI study.

    Science.gov (United States)

    Bodén, R; Persson, J; Wall, A; Lubberink, M; Ekselius, L; Larsson, E-M; Antoni, G

    2017-03-07

    The enzyme phosphodiesterase 10A (PDE10A) is abundant in striatal medium spiny neurons and has been implicated in the pathophysiology of schizophrenia in animal models and is investigated as a possible new pharmacological treatment target. A reduction of prefrontal cortical thickness is common in schizophrenia, but how this relates to PDE10A expression is unknown. Our study aim was to compare, we believe for the first time, the striatal non-displaceable binding potential (BPND) of the new validated PDE10A ligand [(11)C]Lu AE92686 between patients with schizophrenia and healthy controls. Furthermore, we aimed to assess the correlation of PDE10A BPND to cortical thickness. Sixteen healthy male controls and 10 male patients with schizophrenia treated with clozapine, olanzapine or quetiapine were investigated with positron emission tomography (PET) and magnetic resonance imaging (MRI). Striatal binding potential (BPND) of [(11)C]Lu AE92686 was acquired through dynamic PET scans and cortical thickness by structural MRI. Clinical assessments of symptoms and cognitive function were performed and the antipsychotic dosage was recorded. Patients with schizophrenia had a significantly lower BPND of [(11)C]Lu AE92686 in striatum (P=0.003) than healthy controls. The striatal BPND significantly correlated to cortical thickness in the medial prefrontal cortex and superior frontal gyrus across patients with schizophrenia and healthy controls. No significant correlation was observed between the BPND for [(11)C]Lu AE92686 in striatum and age, schizophrenia symptoms, antipsychotic dosage, coffee consumption, smoking, duration of illness or cognitive function in the patients. In conclusion, PDE10A may be important for functioning in the striato-cortical interaction and in the pathophysiology of schizophrenia.

  5. Cortical and trabecular bone adaptation to incremental load magnitudes using the mouse tibial axial compression loading model.

    Science.gov (United States)

    Weatherholt, Alyssa M; Fuchs, Robyn K; Warden, Stuart J

    2013-01-01

    The mouse tibial axial compression loading model has recently been described to allow simultaneous exploration of cortical and trabecular bone adaptation within the same loaded element. However, the model frequently induces cortical woven bone formation and has produced inconsistent results with regards to trabecular bone adaptation. The aim of this study was to investigate bone adaptation to incremental load magnitudes using the mouse tibial axial compression loading model, with the ultimate goal of revealing a load that simultaneously induced lamellar cortical and trabecular bone adaptation. Adult (16 weeks old) female C57BL/6 mice were randomly divided into three load magnitude groups (5, 7 and 9N), and had their right tibia axially loaded using a continuous 2-Hz haversine waveform for 360 cycles/day, 3 days/week for 4 consecutive weeks. In vivo peripheral quantitative computed tomography was used to longitudinally assess midshaft tibia cortical bone adaptation, while ex vivo micro-computed tomography and histomorphometry were used to assess both midshaft tibia cortical and proximal tibia trabecular bone adaptation. A dose response to loading magnitude was observed within cortical bone, with increasing load magnitude inducing increasing levels of lamellar cortical bone adaptation within the upper two thirds of the tibial diaphysis. Greatest cortical bone adaptation was observed at the midshaft where there was a 42% increase in estimated mechanical properties (polar moment of inertia) in the highest (9N) load group. A dose response to load magnitude was not clearly evident within trabecular bone, with only the highest load (9N) being able to induce measureable adaptation (31% increase in trabecular bone volume fraction at the proximal tibia). The ultimate finding was that a load of 9N (engendering a tensile strain of 1833 με on medial surface of the midshaft tibia) was able to simultaneously induce measurable lamellar cortical and trabecular bone adaptation

  6. Alterations in Cortical Thickness and White Matter Integrity in Mild-to-Moderate Communicating Hydrocephalic School-Aged Children Measured by Whole-Brain Cortical Thickness Mapping and DTI

    Science.gov (United States)

    Ye, Xinjian; Bai, Guanghui; Fu, Yuchuan; Mao, Chuanwan; Wu, Aiqin

    2017-01-01

    Follow-up observation is required for mild-to-moderate hydrocephalic patients because of the potential damage to brain. However, effects of mild-to-moderate hydrocephalus on gray and white matter remain unclear in vivo. Using structural MRI and diffusion tensor imaging (DTI), current study compared the cortical thickness and white matter integrity between children with mild-to-moderate communicating hydrocephalus and healthy controls. The relationships between cortical changes and intelligence quota were also examined in patients. We found that cortical thickness in the left middle temporal and left rostral middle frontal gyrus was significantly lower in the hydrocephalus group compared with that of controls. Fractional anisotropy in the right corpus callosum body was significantly lower in the hydrocephalus group compared with that of controls. In addition, there was no association of cortical thinning or white matter fractional anisotropy with intelligence quota in either group. Thus, our findings provide clues to that mild-to-moderate hydrocephalus could lead to structural brain deficits especially in the middle temporal and middle frontal gyrus prior to the behavior changes.

  7. Experimental investigations of forces and torque in conventional and ultrasonically-assisted drilling of cortical bone.

    Science.gov (United States)

    Alam, K; Mitrofanov, A V; Silberschmidt, V V

    2011-03-01

    Bone drilling is widely used in orthopaedics and surgery; it is a technically demanding surgical procedure. Recent technological improvements in this area are focused on efforts to reduce forces in bone drilling. This study focuses on forces and a torque required for conventional and ultrasonically-assisted tool penetration into fresh bovine cortical bone. Drilling tests were performed with two drilling techniques, and the influence of drilling speed, feed rate and parameters of ultrasonic vibration on the forces and torque was studied. Ultrasonically-assisted drilling (UAD) was found to reduce a drilling thrust force and torque compared to conventional drilling (CD). The mechanism behind lower levels of forces and torque was explored, using high-speed filming of a drill-bone interaction zone, and was linked to the chip shape and character of its formation. It is expected that UAD will produce holes with minimal effort and avoid unnecessary damage and accompanying pain during the incision.

  8. CD44 deficiency inhibits unloading-induced cortical bone loss through downregulation of osteoclast activity.

    Science.gov (United States)

    Li, Yuheng; Zhong, Guohui; Sun, Weijia; Zhao, Chengyang; Zhang, Pengfei; Song, Jinping; Zhao, Dingsheng; Jin, Xiaoyan; Li, Qi; Ling, Shukuan; Li, Yingxian

    2015-01-01

    The CD44 is cellular surface adhesion molecule that is involved in physiological processes such as hematopoiesis, lymphocyte homing and limb development. It plays an important role in a variety of cellular functions including adhesion, migration, invasion and survival. In bone tissue, CD44 is widely expressed in osteoblasts, osteoclasts and osteocytes. However, the mechanisms underlying its role in bone metabolism remain unclear. We found that CD44 expression was upregulated during osteoclastogenesis. CD44 deficiency in vitro significantly inhibited osteoclast activity and function by regulating the NF-κB/NFATc1-mediated pathway. In vivo, CD44 mRNA levels were significantly upregulated in osteoclasts isolated from the hindlimb of tail-suspended mice. CD44 deficiency can reduce osteoclast activity and counteract cortical bone loss in the hindlimb of unloaded mice. These results suggest that therapeutic inhibition of CD44 may protect from unloading induced bone loss by inhibiting osteoclast activity.

  9. Guided bone regeneration (GBR) using cortical bone pins in combination with leukocyte- and platelet-rich fibrin (L-PRF).

    Science.gov (United States)

    Toffler, Michael

    2014-03-01

    Two of the fundamental requisites for guided bone regeneration (GBR) are space maintenance and primary soft-tissue closure. Allogeneic cortical bone pins measuring 2 mm in diameter in customized lengths can protect surrounding graft materials, support bioresorbable membrane barriers, and resist wound compression from the overlying soft tissues. In addition, a second-generation platelet concentrate, leukocyte- and platelet-rich fibrin (L-PRF), may be incorporated into the augmentation procedure to provide multiple growth factors, accelerate wound healing, and aid in the maintenance of primary closure over the grafted materials. Highlighting two case reports, this article features a GBR technique that uses bone pins in combination with L-PRF membranes to provide both horizontal and vertical ridge augmentation at severely compromised implant sites.

  10. Experimental multiscale measurements for the mechanical identification of a cortical bone by digital image correlation.

    Science.gov (United States)

    Nguyen, Manh-Tu; Allain, Jean-Marc; Gharbi, Hakim; Desceliers, Christophe; Soize, Christian

    2016-10-01

    The implementation of the experimental methodology by optical measurements of mechanical fields, the development of a test bench, the specimen preparation, the experimental measurements, and the digital image correlation (DIC) method, have already been the object of research in the context of biological materials. Nevertheless, in the framework of the experimental identification of a mesoscopic stochastic model of the random apparent elasticity field, measurements of one specimen is required at both the macroscopic scale and the mesoscopic scale under one single loading. The nature of the cortical bone induces some difficulties, as no single speckled pattern technique is available for simultaneously obtaining the displacement at the macroscopic scale and at the mesoscopic scale. In this paper, we present a multiscale experimental methodology based on (i) an experimental protocol for one specimen of a cortical bone, (ii) its measuring bench, (iii) optical field measurements by DIC method, (iv) the experimental results, and (v) the multiscale experimental identification by solving a statistical inverse problem.

  11. Design and validation of bending test method for characterization of miniature pediatric cortical bone specimens.

    Science.gov (United States)

    Albert, Carolyne I; Jameson, John; Harris, Gerald

    2013-02-01

    Osteogenesis imperfecta is a genetic disorder of bone fragility; however, the effects of this disorder on bone material properties are not well understood. No study has yet measured bone material strength in humans with osteogenesis imperfecta. Small bone specimens are often extracted during routine fracture surgeries in children with osteogenesis imperfecta. These specimens could provide valuable insight into the effects of osteogenesis imperfecta on bone material strength; however, their small size poses a challenge to their mechanical characterization. In this study, a validated miniature three-point bending test is described that enables measurement of the flexural material properties of pediatric cortical osteotomy specimens as small as 5 mm in length. This method was validated extensively using bovine bone, and the effect of span/depth aspect ratio (5 vs 6) on the measured flexural properties was examined. The method provided reasonable results for both Young's modulus and flexural strength in bovine bone. With a span/depth ratio of 6, the median longitudinal modulus and flexural strength results were 16.1 (range: 14.4-19.3)GPa and 251 (range: 219-293)MPa, respectively. Finally, the pilot results from two osteotomy specimens from children with osteogenesis imperfecta are presented. These results provide the first measures of bone material strength in this patient population.

  12. Influence of Alveolar Bone Loss and Cement Layer Thickness on the Biomechanical Behavior of Endodontically Treated Maxillary Incisors: A 3-dimensional Finite Element Analysis.

    Science.gov (United States)

    Dal Piva, Amanda Maria de Oliveira; Tribst, João Paulo Mendes; Souza, Rodrigo Othávio de Assunção E; Borges, Alexandre Luiz Souto

    2017-05-01

    In order to understand the mechanical behavior of a weakened incisor, this study aimed to evaluate the stress distribution caused by different alveolar bone heights and cement layer thickness. A finite element analysis was conducted for this investigation. An intact maxillary central incisor was initially modeled, and the bone of the models was modified in order to simulate 4 levels of bone height: BL0 (no bone loss), BL1 (1/3 bone loss), BL2 (1/2 bone loss), and BL3 (2/3 bone loss). These teeth models were remodeled with a fiber post at 2 different cement thicknesses and restored with a ceramic crown; "A" refers to the well-adapted fiber post (0.3 mm) and "B" to the nonadapted fiber post (1 mm), resulting in 12 models. RelyX ARC (3M ESPE, St Paul, MN) cement was simulated for the cementation of the crowns and fiber posts for all groups. Numeric models received a load of 100 N on the lingual surface. All materials and structures were considered linear elastic, homogeneous, and isotropic. Numeric models were plotted and meshed with isoparametric elements, and results were expressed in maximum principal stress. For fiberglass posts, cement, and dentin, the highest stress concentration occurred in the groups with increased bone loss. For cortical bone, the highest values were for the groups with 1/3 bone loss. A greater thickness of cement layer concentrates more stress. More bone loss and greater CLT were the influential factors in concentrating the stress. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. The effect of osteoporosis treatments on fatigue properties of cortical bone tissue

    Directory of Open Access Journals (Sweden)

    Garry R. Brock

    2015-06-01

    Full Text Available Bisphosphonates are commonly prescribed for treatment of osteoporosis. Long-term use of bisphosphonates has been correlated to atypical femoral fractures (AFFs. AFFs arise from fatigue damage to bone tissue that cannot be repaired due to pharmacologic treatments. Despite fatigue being the primary damage mechanism of AFFs, the effects of osteoporosis treatments on fatigue properties of cortical bone are unknown. To examine if fatigue-life differences occur in bone tissue after different pharmacologic treatments for osteoporosis, we tested bone tissue from the femurs of sheep given a metabolic acidosis diet to induce osteoporosis, followed by treatment with a selective estrogen reception modulator (raloxifene, a bisphosphonate (alendronate or zoledronate, or parathyroid hormone (teriparatide, PTH. Beams of cortical bone tissue were created and tested in four-point bending fatigue to failure. Tissue treated with alendronate had reduced fatigue life and less modulus loss at failure compared with other treatments, while tissue treated with PTH had a prolonged fatigue life. No loss of fatigue life occurred with zoledronate treatment despite its greater binding affinity and potency compared with alendronate. Tissue mineralization measured by microCT did not explain the differences seen in fatigue behavior. Increased fatigue life with PTH suggests that current treatment methods for AFF could have beneficial effects for restoring fatigue life. These results indicate that fatigue life differs with each type of osteoporosis treatment.

  14. Effect of Aging on the Toughness of Human Cortical Bone: Evaluation by R-Curves

    Energy Technology Data Exchange (ETDEWEB)

    Kinney, J

    2004-10-08

    Age-related deterioration of the fracture properties of bone, coupled with increased life expectancy, are responsible for increasing incidence of bone fracture in the elderly, and hence, an understanding of how its fracture properties degrade with age is essential. The present study describes ex vivo fracture experiments to quantitatively assess the effect of aging on the fracture toughness properties of human cortical bone in the longitudinal direction. Because cortical bone exhibits rising crack-growth resistance with crack extension, unlike most previous studies the toughness is evaluated in terms of resistance-curve (R-curve) behavior, measured for bone taken from wide range of age groups (34-99 years). Using this approach, both the ex vivo crack-initiation and crack-growth toughness are determined and are found to deteriorate with age; the initiation toughness decreases some 40% over six decades from 40 to 100 years, while the growth toughness is effectively eliminated over the same age range. The reduction in crack-growth toughness is considered to be associated primarily with a degradation in the degree of extrinsic toughening, in particular involving crack bridging in the wake of the crack.

  15. Effect of Loading Rate and Orientation on the Compressive Response of Human Cortical Bone

    Science.gov (United States)

    2014-05-01

    Biomechanics 1975, 8, 27–40. 11. Ntim, M. M.; Bembey, A. K.; Ferguson, V. I.; Bushby, A. J. Hydration Effects on the Viscoelastic Properties of Collagen. MRS...Determination of Mechanical Properties of Human Femoral Cortical Bone by the Hopkinson Bar Stress Technique. Journal of Biomechanics 1990, 23 (11...Science and Technology 2011, 25 (9), 2211–2215. 18. Chen, W.; Song, B. Split Hopkinson (Kolsky) Bar; Springer : New York, 2010; pp 29–77. 19. Kulin, R

  16. Study of the mechanical behavior of cortical bone microstructure by the finite element method

    OpenAIRE

    Arango Villegas, Camila

    2016-01-01

    [EN] Cortical bone tissue is the responsible of giving support and structure to vertebrates. For that reason, understanding and analyzing its behavior is needed from each different hierarchical level that composes it. The lower the structural scale is, the greater the complexity and scarcity of studies in literature. These studies are relevant for understanding, preventing and solving important health problems that affect human beings. From a mechanical point of view is interesting to eval...

  17. Osteostatin-coated porous titanium can improve early bone regeneration of cortical bone defects in rats

    NARCIS (Netherlands)

    Van Der Stok, Johan; Lozano, Daniel; Chai, Yoke Chin; Amin Yavari, Saber; Bastidas Coral, Angela P.; Verhaar, Jan A N; Gómez-Barrena, Enrique; Schrooten, Jan; Jahr, Holger; Zadpoor, Amir A.; Esbrit, Pedro; Weinans, Harrie

    2015-01-01

    A promising bone graft substitute is porous titanium. Porous titanium, produced by selective laser melting (SLM), can be made as a completely open porous and load-bearing scaffold that facilitates bone regeneration through osteoconduction. In this study, the bone regenerative capacity of porous tita

  18. Orbital Emphysema Causing SyncopeChiari Malformation with Thick Occipital Bone

    Directory of Open Access Journals (Sweden)

    Yasuhara,Takao

    2011-02-01

    Full Text Available A case of a Chiari malformation with an extraordinarily thick occipital bone is described. The thick occipital bone might make the posterior fossa narrow with consequent herniation of the cerebellar tonsils to the foramen magnum and formation of a syrinx. At dural plasty, well-developed marginal and occipital sinuses should be deliberately handled with the preservation of normal venous drainage. This case gives us the essence of the occurrence mechanisms of Chiari malformation and foramen magnum decompression.

  19. Does weight gain induce cortical and trabecular bone regain in anorexia nervosa? A two-year prospective study.

    Science.gov (United States)

    Milos, Gabriella; Spindler, Anja; Rüegsegger, Peter; Hasler, Gregor; Schnyder, Ulrich; Laib, Andres; Gallo, Luigi M; Uebelhart, Daniel; Häuselmann, Hansjörg

    2007-11-01

    This prospective study examines bone density and structure over a two-year time period in women with anorexia nervosa (AN) under weight gain treatment. Twenty-four women with AN were examined at baseline and at two annual follow-up examinations. In 9 AN patients BMI increased whereas in 15 it remained unchanged or decreased. Dual energy X-ray absorptiometry (DXA) was performed on the lumbar spine, the femoral neck and the whole hip and three-dimensional peripheral quantitative computer tomography (3D-pQCT) was performed on the ultradistal radius. ANOVAs for repeated measures were used to examine change over time in BMI and bone parameters. At baseline, patients with increased BMI had significantly higher bone density of femoral neck and total hip, and higher levels in all 3D-pQCT parameters of the ultradistal radius, compared to the group with unchanged or decreased BMI. The two groups did not differ at baseline in bone density of the spine. ANOVAs showed that bone density of the total hip increased significantly and that overall bone density (D100), the density of the trabecular area (D.Trab.) and the cortical thickness (C.Th.) in the ultradistal radius decreased significantly. Group x time interactions showed that changes over time were different in the two groups with regard to spine density and in the parameters D100, D.Trab. and C.Th. of the ultradistal radius. In the group with increased BMI the spine density dropped at the first follow-up whereas at the second follow-up it rose again to baseline. Patients with unchanged or decreased BMI showed a small but steady increase in spine density. The group changes of D100, D.Trab. and C.Th. of the ultradistal radius all followed the same pattern. Bone mineral density at all locations measured with both technologies (DXA and 3D-pQCT) did not vary according to BMI changes. The course of bone density and structure at different locations was different, and, despite weight increase, bone regain appeared to need different

  20. Investigation of hyperelastic models for nonlinear elastic behavior of demineralized and deproteinized bovine cortical femur bone.

    Science.gov (United States)

    Hosseinzadeh, M; Ghoreishi, M; Narooei, K

    2016-06-01

    In this study, the hyperelastic models of demineralized and deproteinized bovine cortical femur bone were investigated and appropriate models were developed. Using uniaxial compression test data, the strain energy versus stretch was calculated and the appropriate hyperelastic strain energy functions were fitted on data in order to calculate the material parameters. To obtain the mechanical behavior in other loading conditions, the hyperelastic strain energy equations were investigated for pure shear and equi-biaxial tension loadings. The results showed the Mooney-Rivlin and Ogden models cannot predict the mechanical response of demineralized and deproteinized bovine cortical femur bone accurately, while the general exponential-exponential and general exponential-power law models have a good agreement with the experimental results. To investigate the sensitivity of the hyperelastic models, a variation of 10% in material parameters was performed and the results indicated an acceptable stability for the general exponential-exponential and general exponential-power law models. Finally, the uniaxial tension and compression of cortical femur bone were studied using the finite element method in VUMAT user subroutine of ABAQUS software and the computed stress-stretch curves were shown a good agreement with the experimental data.

  1. Use of Cortical Bone Screws in Maxillofacial Surgery - A Prospective Study

    Science.gov (United States)

    Satish, Madatanapalli; Rahman, NM Mujeeb; Reddy, V Sridhar; Yuvaraj, A; Muliyar, Sabir; Razak, P Abdul

    2014-01-01

    Background: The aim of this study is to evaluate the various applications of cortical bone screws in oral and maxillofacial surgery. Materials & Methods: The study was conducted in a teaching hospital located in, Bangalore, India, on 20 patients. These patients were categorized into three groups depending on the applications of these screws like, for achieving intermaxillary fixation in Group-1, for treatment of simple, undisplaced fractures by “Tension wire” method in Group-2, and further application of these screws were evaluated in Group-3. Different parameters were used to evaluate the efficacy of these screws. Results: In Group-1(n=12) there was satisfactory occlusion in all the patients with minimal incidence of complications. In Group-2 (n=4) post-operative reduction and fixation was satisfactory and in Group-3 (n=4) the function of these screws was satisfactory when it was used for vestibuloplasty and also as a suspension wiring in treatment of comminuted fracture of zygoma with minimal incidence of complications. Conclusion: Use of cortical bone screws is a valid alternative for achieving intermaxillary fixation, reduction and fixation of simple, undisplaced or minimally displaced fractures through Tension wire method owing to its simplicity, economy and ease of use, and as a fixation method for apically positioned flap in vestibuloplasty procedure. How to cite the article: Satish M, Rahman NM, Reddy VS, Yuvaraj A, Muliyar S, Razak PA. Use of Cortical Bone Screws in Maxillofacial Surgery - A Prospective Study. J Int Oral Health 2014;6(2):62-7. PMID:24876704

  2. Cortical Thickness in Dementia with Lewy Bodies and Alzheimer's Disease: A Comparison of Prodromal and Dementia Stages.

    Directory of Open Access Journals (Sweden)

    Frederic Blanc

    Full Text Available To assess and compare cortical thickness (CTh of patients with prodromal Dementia with Lewy bodies (pro-DLB, prodromal Alzheimer's disease (pro-AD, DLB dementia (DLB-d, AD dementia (AD-d and normal ageing.Study participants(28 pro-DLB, 27 pro-AD, 31 DLB-d, 54 AD-d and 33 elderly controls underwent 3Tesla T1 3D MRI and detailed clinical and cognitive assessments. We used FreeSurfer analysis package to measure CTh and investigate patterns of cortical thinning across groups.Comparison of CTh between pro-DLB and pro-AD (p<0.05, FDR corrected showed more right anterior insula thinning in pro-DLB, and more bilateral parietal lobe and left parahippocampal gyri thinning in pro-AD. Comparison of prodromal patients to healthy elderly controls showed the involvement of the same regions. In DLB-d (p<0.05, FDR corrected cortical thinning was found predominantly in the right temporo-parietal junction, and insula, cingulate, orbitofrontal and lateral occipital cortices. In AD-d(p<0.05, FDR corrected,the most significant areas affected included the entorhinal cortices, parahippocampal gyri and parietal lobes. The comparison of AD-d and DLB-d demonstrated more CTh in AD-d in the left entorhinal cortex (p<0.05, FDR corrected.Cortical thickness is a sensitive measure for characterising patterns of grey matter atrophy in early stages of DLB distinct from AD. Right anterior insula involvement may be a key region at the prodromal stage of DLB and needs further investigation.

  3. Soluble VEGFR1 reverses BMP2 inhibition of intramembranous ossification during healing of cortical bone defects.

    Science.gov (United States)

    Hu, Kai; Besschetnova, Tatiana Y; Olsen, Bjorn R

    2016-09-07

    BMP2 is widely used for promotion of bone repair and regeneration. However, bone formation induced by BMP2 is quite variable. Bone forming progenitor cells in different locations appear to respond to BMP2 in different ways, and repair outcomes can vary as a consequence of modulating effects by other factors. In this study, we have examined the effects of VEGF on BMP2-induced repair of a cortical bone defect, a 1 mm diameter drill hole, in the proximal tibia of mice. Treatment of the defect with either a bolus of PBS or soluble VEGFR1 (sVEGFR1), a decoy receptor for VEGF, had the same effects on bone formation via intramembranous ossification in the defect and cartilage formation and injured periosteum, during the healing process. In contrast, treatment with BMP2 inhibited intramembranous bone formation in the defect while it promoted cartilage and endochondral bone formation in the injured periosteum compared with mice treated with PBS or sVEGFR1. The inhibitory effect of BMP2 on bone formation was unlikely due to increased osteoclast activity and decreased invasion of blood vessels in the defect. Most importantly, co-delivery of BMP2 and sVEGFR1 reversed the inhibition of intramembranous bone formation by BMP2. Furthermore, the decreased accumulation of collagen and production of bone matrix proteins in the defect of groups with BMP2 treatment could also be prevented by co-delivery of BMP2 and sVEGFR1. Our data indicate that introducing a VEGF-binding protein, such as sVEGFR1, to reduce levels of extracellular VEGF, may enhance the effects of BMP2 on intramembranous bone formation. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

  4. Mechanical strain, induced noninvasively in the high-frequency domain, is anabolic to cancellous bone, but not cortical bone.

    Science.gov (United States)

    Rubin, C; Turner, A S; Mallinckrodt, C; Jerome, C; McLeod, K; Bain, S

    2002-03-01

    Departing from the premise that it is the large-amplitude signals inherent to intense functional activity that define bone morphology, we propose that it is the far lower magnitude, high-frequency mechanical signals that continually barrage the skeleton during longer term activities such as standing, which regulate skeletal architecture. To examine this hypothesis, we proposed that brief exposure to slight elevations in these endogenous mechanical signals would suffice to increase bone mass in those bones subject to the stimulus. This was tested by exposing the hind limbs of adult female sheep (n = 9) to 20 min/day of low-level (0.3g), high-frequency (30 Hz) mechanical signals, sufficient to induce a peak of approximately 5 microstrain (micro epsilon) in the tibia. Following euthanasia, peripheral quantitative computed tomography (pQCT) was used to segregate the cortical shell from the trabecular envelope of the proximal femur, revealing a 34.2% increase in bone density in the experimental animals as compared with controls (p = 0.01). Histomorphometric examination of the femur supported these density measurements, with bone volume per total volume increasing by 32% (p = 0.04). This density increase was achieved by two separate strategies: trabecular spacing decreased by 36.1% (p = 0.02), whereas trabecular number increased by 45.6% (p = 0.01), indicating the formation of cancellous bone de novo. There were no significant differences in the radii of animals subject to the stimulus, indicating that the adaptive response was local rather than systemic. The anabolic potential of the signal was evident only in trabecular bone, and there were no differences, as measured by any assay, in the cortical bone. These data suggest that subtle mechanical signals generated during predominant activities such as posture may be potent determinants of skeletal morphology. Given that these strain levels are three orders of magnitude below strains that can damage bone tissue, we

  5. Organizing Principles of Human Cortical Development--Thickness and Area from 4 to 30 Years: Insights from Comparative Primate Neuroanatomy.

    Science.gov (United States)

    Amlien, Inge K; Fjell, Anders M; Tamnes, Christian K; Grydeland, Håkon; Krogsrud, Stine K; Chaplin, Tristan A; Rosa, Marcello G P; Walhovd, Kristine B

    2016-01-01

    The human cerebral cortex undergoes a protracted, regionally heterogeneous development well into young adulthood. Cortical areas that expand the most during human development correspond to those that differ most markedly when the brains of macaque monkeys and humans are compared. However, it remains unclear to what extent this relationship derives from allometric scaling laws that apply to primate brains in general, or represents unique evolutionary adaptations. Furthermore, it is unknown whether the relationship only applies to surface area (SA), or also holds for cortical thickness (CT). In 331 participants aged 4 to 30, we calculated age functions of SA and CT, and examined the correspondence of human cortical development with macaque to human expansion, and with expansion across nonhuman primates. CT followed a linear negative age function from 4 to 30 years, while SA showed positive age functions until 12 years with little further development. Differential cortical expansion across primates was related to regional maturation of SA and CT, with age trajectories differing between high- and low-expanding cortical regions. This relationship adhered to allometric scaling laws rather than representing uniquely macaque-human differences: regional correspondence with human development was as large for expansion across nonhuman primates as between humans and macaque.

  6. Primary somatosensory/motor cortical thickness distinguishes paresthesia-dominant from pain-dominant carpal tunnel syndrome.

    Science.gov (United States)

    Maeda, Yumi; Kettner, Norman; Kim, Jieun; Kim, Hyungjun; Cina, Stephen; Malatesta, Cristina; Gerber, Jessica; McManus, Claire; Libby, Alexandra; Mezzacappa, Pia; Mawla, Ishtiaq; Morse, Leslie R; Audette, Joseph; Napadow, Vitaly

    2016-05-01

    Paresthesia-dominant and pain-dominant subgroups have been noted in carpal tunnel syndrome (CTS), a peripheral neuropathic disorder characterized by altered primary somatosensory/motor (S1/M1) physiology. We aimed to investigate whether brain morphometry dissociates these subgroups. Subjects with CTS were evaluated with nerve conduction studies, whereas symptom severity ratings were used to allocate subjects into paresthesia-dominant (CTS-paresthesia), pain-dominant (CTS-pain), and pain/paresthesia nondominant (not included in further analysis) subgroups. Structural brain magnetic resonance imaging data were acquired at 3T using a multiecho MPRAGE T1-weighted pulse sequence, and gray matter cortical thickness was calculated across the entire brain using validated, automated methods. CTS-paresthesia subjects demonstrated reduced median sensory nerve conduction velocity (P = 0.05) compared with CTS-pain subjects. In addition, cortical thickness in precentral and postcentral gyri (S1/M1 hand area) contralateral to the more affected hand was significantly reduced in CTS-paresthesia subgroup compared with CTS-pain subgroup. Moreover, in CTS-paresthesia subjects, precentral cortical thickness was negatively correlated with paresthesia severity (r(34) = -0.40, P = 0.016) and positively correlated with median nerve sensory velocity (r(36) = 0.51, P = 0.001), but not with pain severity. Conversely, in CTS-pain subjects, contralesional S1 (r(9) = 0.62, P = 0.042) and M1 (r(9) = 0.61, P = 0.046) cortical thickness were correlated with pain severity, but not median nerve velocity or paresthesia severity. This double dissociation in somatotopically specific S1/M1 areas suggests a neuroanatomical substrate for symptom-based CTS subgroups. Such fine-grained subgrouping of CTS may lead to improved personalized therapeutic approaches, based on superior characterization of the linkage between peripheral and central neuroplasticity.

  7. The Right Hemisphere Planum Temporale Supports Enhanced Visual Motion Detection Ability in Deaf People: Evidence from Cortical Thickness

    Directory of Open Access Journals (Sweden)

    Martha M. Shiell

    2016-01-01

    Full Text Available After sensory loss, the deprived cortex can reorganize to process information from the remaining modalities, a phenomenon known as cross-modal reorganization. In blind people this cross-modal processing supports compensatory behavioural enhancements in the nondeprived modalities. Deaf people also show some compensatory visual enhancements, but a direct relationship between these abilities and cross-modally reorganized auditory cortex has only been established in an animal model, the congenitally deaf cat, and not in humans. Using T1-weighted magnetic resonance imaging, we measured cortical thickness in the planum temporale, Heschl’s gyrus and sulcus, the middle temporal area MT+, and the calcarine sulcus, in early-deaf persons. We tested for a correlation between this measure and visual motion detection thresholds, a visual function where deaf people show enhancements as compared to hearing. We found that the cortical thickness of a region in the right hemisphere planum temporale, typically an auditory region, was greater in deaf individuals with better visual motion detection thresholds. This same region has previously been implicated in functional imaging studies as important for functional reorganization. The structure-behaviour correlation observed here demonstrates this area’s involvement in compensatory vision and indicates an anatomical correlate, increased cortical thickness, of cross-modal plasticity.

  8. A longitudinal study of atrophy in amnestic mild cognitive impairment and normal aging revealed by cortical thickness.

    Directory of Open Access Journals (Sweden)

    Zhijun Yao

    Full Text Available In recent years, amnestic mild cognitive impairment (aMCI has attracted significant attention as an indicator of high risk for Alzheimer's disease. An understanding of the pathology of aMCI may benefit the development of effective clinical treatments for dementia. In this work, we measured the cortical thickness of 109 aMCI subjects and 99 normal controls (NC twice over two years. The longitudinal changes and the cross-sectional differences between the two types of participants were explored using the vertex thickness values. The thickness of the cortex in aMCI was found significantly reduced in both longitudinal and between-group comparisons, mainly in the temporal lobe, superolateral parietal lobe and some regions of the frontal cortices. Compared to NC, the aMCI showed a significantly high atrophy rate in the left lateral temporal lobe and left parahippocampal gyrus over two years. Additionally, a significant positive correlation between brain atrophy and the decline of Mini-Mental State Examination (MMSE scores was also found in the left superior and left middle temporal gyrus in aMCI. These findings demonstrated specific longitudinal spatial patterns of cortical atrophy in aMCI and NC. The higher atrophy rate in aMCI might be responsible for the accelerated functional decline in the aMCI progression process.

  9. A longitudinal study of atrophy in amnestic mild cognitive impairment and normal aging revealed by cortical thickness.

    Science.gov (United States)

    Yao, Zhijun; Hu, Bin; Liang, Chuanjiang; Zhao, Lina; Jackson, Mike

    2012-01-01

    In recent years, amnestic mild cognitive impairment (aMCI) has attracted significant attention as an indicator of high risk for Alzheimer's disease. An understanding of the pathology of aMCI may benefit the development of effective clinical treatments for dementia. In this work, we measured the cortical thickness of 109 aMCI subjects and 99 normal controls (NC) twice over two years. The longitudinal changes and the cross-sectional differences between the two types of participants were explored using the vertex thickness values. The thickness of the cortex in aMCI was found significantly reduced in both longitudinal and between-group comparisons, mainly in the temporal lobe, superolateral parietal lobe and some regions of the frontal cortices. Compared to NC, the aMCI showed a significantly high atrophy rate in the left lateral temporal lobe and left parahippocampal gyrus over two years. Additionally, a significant positive correlation between brain atrophy and the decline of Mini-Mental State Examination (MMSE) scores was also found in the left superior and left middle temporal gyrus in aMCI. These findings demonstrated specific longitudinal spatial patterns of cortical atrophy in aMCI and NC. The higher atrophy rate in aMCI might be responsible for the accelerated functional decline in the aMCI progression process.

  10. A mathematical model of cortical bone remodeling at cellular level under mechanical stimulus

    Institute of Scientific and Technical Information of China (English)

    Qing-Hua Qin; Ya-Nan Wang

    2012-01-01

    A bone cell population dynamics model for cortical bone remodeling under mechanical stimulus is developed in this paper.The external experiments extracted from the literature which have not been used in the creation of the model are used to test the validity of the model.Not only can the model compare reasonably well with these experimental results such as the increase percentage of final values of bone mineral content (BMC) and bone fracture energy (BFE) among different loading schemes (which proves the validity of the model),but also predict the realtime development pattern of BMC and BFE,as well as the dynamics of osteoblasts (OBA),osteoclasts (OCA),nitric oxide (NO) and prostaglandin E2 (PGE2) for each loading scheme,which can hardly be monitored through experiment.In conclusion,the model is the first of its kind that is able to provide an insight into the quantitative mechanism of bone remodeling at cellular level by which bone cells are activated by mechanical stimulus in order to start resorption/formation of bone mass.More importantly,this model has laid a solid foundation based on which future work such as systemic control theory analysis of bone remodeling under mechanical stimulus can be investigated.The to-be identified control mechanism will help to develop effective drugs and combined nonpharmacological therapies to combat bone loss pathologies.Also this deeper understanding of how mechanical forces quantitatively interact with skeletal tissue is essential for the generation of bone tissue for tissue replacement purposes in tissue engineering.

  11. Neutron activation analysis of medullar and cortical bone tissues from animals; Analise por ativacao com neutrons de tecidos osseos medular e cortical de animais

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    Takata, Marcelo Kazuo; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica

    2000-07-01

    In this work, neutron activation analysis was applied in the determination of the elements Ba, Br, Ca, Cl, Cr, Fe, K, Mg, Mn, Na, P, Rb, Sb, Sc, Sr and Zn present in animal bone tissues. The obtained results indicated a significant difference between the elemental concentrations present in medullar and cortical tissues. The results obtained for bone tissues from distinct animal species were also different. (author)

  12. Microcomputed tomographic analysis of human condyles in unilateral condylar hyperplasia: increased cortical porosity and trabecular bone volume fraction with reduced mineralisation.

    Science.gov (United States)

    Karssemakers, L H E; Nolte, J W; Tuinzing, D B; Langenbach, G E J; Raijmakers, P G; Becking, A G

    2014-12-01

    Unilateral condylar hyperplasia or hyperactivity is a disorder of growth that affects the mandible, and our aim was to visualise the 3-dimensional bony microstructure of resected mandibular condyles of affected patients. We prospectively studied 17 patients with a clinical presentation of progressive mandibular asymmetry and an abnormal single-photon emission computed tomographic (SPECT) scan. All patients were treated by condylectomy to arrest progression. The resected condyles were scanned with micro-CT (18 μm resolution). Rectangular volumes of interest were selected in 4 quadrants (lateromedial and superoinferior) of the trabecular bone of each condyle. Variables of bone architecture (volume fraction, trabecular number, thickness, and separation, degree of mineralisation, and degree of structural anisotrophy) were calculated with routine morphometric software. Eight of the 17 resected condyles showed clear destruction of the subchondral layer of cortical bone. There was a significant superoinferior gradient for all trabecular variables. Mean (SD) bone volume fraction (25.1 (6) %), trabecular number (1.69 (0.26) mm(-1)), trabecular thickness (0.17 (0.03) mm), and degree of mineralisation (695.39 (39.83) mg HA/cm(3)) were higher in the superior region. Trabecular separation (0.6 (0.16) mm) and structural anisotropy (1.84 (0.28)) were higher in the inferior region. The micro-CT analysis showed increased cortical porosity in many of the condyles studied. It also showed a higher bone volume fraction, greater trabecular thickness and trabecular separation, greater trabecular number, and less mineralisation in the condyles of the 17 patients compared with the known architecture of unaffected mandibular condyles.

  13. Mild traumatic brain injury is associated with reduced cortical thickness in those at risk for Alzheimer's disease.

    Science.gov (United States)

    Hayes, Jasmeet P; Logue, Mark W; Sadeh, Naomi; Spielberg, Jeffrey M; Verfaellie, Mieke; Hayes, Scott M; Reagan, Andrew; Salat, David H; Wolf, Erika J; McGlinchey, Regina E; Milberg, William P; Stone, Annjanette; Schichman, Steven A; Miller, Mark W

    2017-03-01

    Moderate-to-severe traumatic brain injury is one of the strongest environmental risk factors for the development of neurodegenerative diseases such as late-onset Alzheimer's disease, although it is unclear whether mild traumatic brain injury, or concussion, also confers risk. This study examined mild traumatic brain injury and genetic risk as predictors of reduced cortical thickness in brain regions previously associated with early Alzheimer's disease, and their relationship with episodic memory. Participants were 160 Iraq and Afghanistan War veterans between the ages of 19 and 58, many of whom carried mild traumatic brain injury and post-traumatic stress disorder diagnoses. Whole-genome polygenic risk scores for the development of Alzheimer's disease were calculated using summary statistics from the largest Alzheimer's disease genome-wide association study to date. Results showed that mild traumatic brain injury moderated the relationship between genetic risk for Alzheimer's disease and cortical thickness, such that individuals with mild traumatic brain injury and high genetic risk showed reduced cortical thickness in Alzheimer's disease-vulnerable regions. Among males with mild traumatic brain injury, high genetic risk for Alzheimer's disease was associated with cortical thinning as a function of time since injury. A moderated mediation analysis showed that mild traumatic brain injury and high genetic risk indirectly influenced episodic memory performance through cortical thickness, suggesting that cortical thinning in Alzheimer's disease-vulnerable brain regions is a mechanism for reduced memory performance. Finally, analyses that examined the apolipoprotein E4 allele, post-traumatic stress disorder, and genetic risk for schizophrenia and depression confirmed the specificity of the Alzheimer's disease polygenic risk finding. These results provide evidence that mild traumatic brain injury is associated with greater neurodegeneration and reduced memory performance

  14. Decreased bone turnover with balanced resorption and formation prevent cortical bone loss during disuse (hibernation) in grizzly bears (Ursus arctos horribilis).

    Science.gov (United States)

    McGee, Meghan E; Maki, Aaron J; Johnson, Steven E; Nelson, O Lynne; Robbins, Charles T; Donahue, Seth W

    2008-02-01

    Disuse uncouples bone formation from resorption, leading to increased porosity, decreased bone geometrical properties, and decreased bone mineral content which compromises bone mechanical properties and increases fracture risk. However, black bear bone properties are not adversely affected by aging despite annual periods of disuse (i.e., hibernation), which suggests that bears either prevent bone loss during disuse or lose bone and subsequently recover it at a faster rate than other animals. Here we show decreased cortical bone turnover during hibernation with balanced formation and resorption in grizzly bear femurs. Hibernating grizzly bear femurs were less porous and more mineralized, and did not demonstrate any changes in cortical bone geometry or whole bone mechanical properties compared to active grizzly bear femurs. The activation frequency of intracortical remodeling was 75% lower during hibernation than during periods of physical activity, but the normalized mineral apposition rate was unchanged. These data indicate that bone turnover decreases during hibernation, but osteons continue to refill at normal rates. There were no changes in regional variation of porosity, geometry, or remodeling indices in femurs from hibernating bears, indicating that hibernation did not preferentially affect one region of the cortex. Thus, grizzly bears prevent bone loss during disuse by decreasing bone turnover and maintaining balanced formation and resorption, which preserves bone structure and strength. These results support the idea that bears possess a biological mechanism to prevent disuse osteoporosis.

  15. Relationship between neurotoxic kynurenine metabolites and reductions in right medial prefrontal cortical thickness in major depressive disorder.

    Science.gov (United States)

    Meier, Timothy B; Drevets, Wayne C; Wurfel, Brent E; Ford, Bart N; Morris, Harvey M; Victor, Teresa A; Bodurka, Jerzy; Teague, T Kent; Dantzer, Robert; Savitz, Jonathan

    2016-03-01

    Reductions in gray matter volume of the medial prefrontal cortex (mPFC), especially the rostral and subgenual anterior cingulate cortex (rACC, sgACC) are a widely reported finding in major depressive disorder (MDD). Inflammatory mediators, which are elevated in a subgroup of patients with MDD, activate the kynurenine metabolic pathway and increase production of neuroactive metabolites such as kynurenic acid (KynA), 3-hydroxykynurenine (3HK) and quinolinic acid (QA) which influence neuroplasticity. It is not known whether the alterations in brain structure and function observed in major depressive disorders are due to the direct effect of inflammatory mediators or the effects of neurotoxic kynurenine metabolites. Here, using partial posterior predictive distribution mediation analysis, we tested whether the serum concentrations of kynurenine pathway metabolites mediated reductions in cortical thickness in mPFC regions in MDD. Further, we tested whether any association between C-reactive protein (CRP) and cortical thickness would be mediated by kynurenine pathway metabolites. Seventy-three unmedicated subjects who met DSM-IV-TR criteria for MDD and 91 healthy controls (HC) completed MRI scanning using a pulse sequence optimized for tissue contrast resolution. Automated cortical parcellation was performed using the PALS-B12 Brodmann area atlas as implemented in FreeSurfer in order to compare the cortical thickness and cortical area of six PFC regions: Brodmann areas (BA) 9, 10, 11, 24, 25, and 32. Serum concentrations of kynurenine pathway metabolites were determined by high performance liquid chromatography (HPLC) with tandem mass spectrometry (MS/MS) detection, while high-sensitivity CRP concentration was measured immunoturbidimetrically. Compared with HCs, the MDD group showed a reduction in cortical thickness of the right BA24 (pdepressive episodes displayed thinner cortex in BA32 (p<0.05). Consistent with our previous findings in an overlapping sample, the KynA/3

  16. Cluster analysis of infrared spectra of rabbit cortical bone samples during maturation and growth.

    Science.gov (United States)

    Kobrina, Yevgeniya; Turunen, Mikael J; Saarakkala, Simo; Jurvelin, Jukka S; Hauta-Kasari, Markku; Isaksson, Hanna

    2010-12-01

    Bone consists of an organic and an inorganic matrix. During development, bone undergoes changes in its composition and structure. In this study we apply three different cluster analysis algorithms [K-means (KM), fuzzy C-means (FCM) and hierarchical clustering (HCA)], and discriminant analysis (DA) on infrared spectroscopic data from developing cortical bone with the aim of comparing their ability to correctly classify the samples into different age groups. Cortical bone samples from the mid-diaphysis of the humerus of New Zealand white rabbits from three different maturation stages (newborn (NB), immature (11 days-1 month old), mature (3-6 months old)) were used. Three clusters were obtained by KM, FCM and HCA methods on different spectral regions (amide I, phosphate and carbonate). The newborn samples were well separated (71-100% correct classifications) from the other age groups by all bone components. The mature samples (3-6 months old) were well separated (100%) from those of other age groups by the carbonate spectral region, while by the phosphate and amide I regions some samples were assigned to another group (43-71% correct classifications). The greatest variance in the results for all algorithms was observed in the amide I region. In general, FCM clustering performed better than the other methods, and the overall error was lower. The discriminate analysis results showed that by combining the clustering results from all three spectral regions, the ability to predict the correct age group for all samples increased (from 29-86% to 77-91%). This study is the first to compare several clustering methods on infrared spectra of bone. Fuzzy C-means clustering performed best, and its ability to study the degree of memberships of samples to each cluster might be beneficial in future studies of medical diagnostics.

  17. Selective laser melting-produced porous titanium scaffolds regenerate bone in critical size cortical bone defects

    NARCIS (Netherlands)

    J. van der Stok (Johan); O.P. van der Jagt (Olav); S. Amin Yavari (Saber); M.F.P. de Haas (Mirthe); J.H. Waarsing (Jan); H. Jahr (Holger); E.M.M. van Lieshout (Esther); P. Patka (Peter); J.A.N. Verhaar (Jan); A.A. Zadpoor (Amir Abbas); H.H. Weinans (Harrie)

    2013-01-01

    textabstractPorous titanium scaffolds have good mechanical properties that make them an interesting bone substitute material for large bone defects. These scaffolds can be produced with selective laser melting, which has the advantage of tailoring the structure's architecture. Reducing the strut siz

  18. The relationship between the mechanical anisotropy of human cortical bone tissue and its microstructure

    Science.gov (United States)

    Espinoza Orias, Alejandro A.

    Orthopedics research has made significant advances in the areas of biomechanics, bone implants and bone substitute materials. However, to date there is no definitive model to explain the structure-property relationships in bone as a material to enable better implant designs or to develop a true biomechanical analog of bone. The objective of this investigation was to establish a relationship between the elastic anisotropy of cortical bone tissue and its microstructure. Ultrasonic wave propagation was used to measure stiffness coefficients for specimens sectioned along the length of a human femur. The elastic constants were orthotropic and varied with anatomical location. Stiffness coefficients were generally largest at the midshaft and stiffness anisotropy ratios were largest at the distal and proximal ends. These tests were run on four additional human femurs to assess the influence of phenotypic variation, and in most cases, it was found that phenotypes do not exert a significant effect. Stiffness coefficients were shown to be correlated as a power law relation to apparent density, but anisotropy ratios were not. Texture analysis was performed on selected samples to measure the orientation distribution of the bone mineral crystals. Inverse pole figures showed that bone mineral crystals had a preferred crystallographic orientation, coincident with the long axis of the femur, which is its principal loading direction. The degree of preferred orientation was represented in Multiples of a Random Distribution (MRD), and correlated to the anisotropy ratios. Variation in elastic anisotropy was shown to be primarily due to the bone mineral orientation. The results found in this work can be used to incorporate anisotropy into structural analysis for bone as a material.

  19. In Vitro Fracture of Human Cortical Bone: Local Fracture Criteria and Toughening Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Nalla, R; Stolken, J; Kinney, J; Ritchie, R

    2004-08-18

    A micro-mechanistic understanding of bone fracture that encompasses how cracks interact with the underlying microstructure and defines their local failure mode is lacking, despite extensive research on the response of bone to a variety of factors like aging, loading, and/or disease. Micro-mechanical models for fracture incorporating such local failure criteria have been widely developed for metallic and ceramic materials systems; however, few such deliberations have been undertaken for the fracture of bone. In fact, although the fracture event in mineralized tissues such as bone is commonly believed to be locally strain controlled, until recently there has been little experimental evidence to support this widely held belief. In the present study, a series of in vitro experiments involving a double-notch bend test geometry are performed in order to shed further light on the nature of the local cracking events that precede catastrophic fracture in bone and to define their relationship to the microstructure. Specifically, crack-microstructure interactions are examined to determine the salient toughening mechanisms in human cortical bone and to characterize how these may affect the anisotropy in fracture properties. Based on preliminary micro-mechanical models of these processes, in particular crack deflection and uncracked ligament bridging, the relative importance of these toughening mechanisms is established.

  20. A surface based approach for cortical thickness comparison between PiB+ and PiB- healthy control subjects

    Science.gov (United States)

    Doré, Vincent; Bourgeat, Pierrick; Fripp, Jurgen; Acosta, Oscar; Chetelat, Gael; Szoeke, Cassandra; Ellis, Kathryn A.; Martins, Ralph N.; Villemagne, Victor; Masters, Colin L.; Ames, David; Rowe, Christopher C.; Salvado, Olivier

    2012-02-01

    β-amyloid has been shown to play a crucial role in Alzheimer's disease (AD). In vivo β-amyloid imaging using [11C]Pittsburgh compound Β (PiB) positron emission tomography has made it possible to analyze the relationship between β-amyloid deposition and different pathological markers involved in AD. PiB allows us to stratify the population between subjects which are likely to have prodromal AD, and those who don't. The comparison of the cortical thickness in these different groups is important to better understanding and detect the first symptoms of the disease which may lead to an earlier therapeutic care to reduce neurone loss. Several techniques have been developed to compare the cortical volume and/or thickness between AD and HC groups. However due to the noise introduced by the cortical thickness estimation and by the registration, these methods do not allow to unveil any major different when comparing prodromal AD groups with healthy control subjects group. To improve our understanding of where initial Alzheimer neurodegeneration occurs in the cortex we have developed a surface based technique, and have applied it to the discrimination between PIB-positive and PiB-negative HCs. We first identify the regions where AD patients show high cortical atrophy by using an AD/PiB- HC vertex-wise T-test. In each of these discriminating regions, comparison between PiB+ HC, PiB- HC and AD are performed. We found some significant differences between the two HC groups in the hippocampus and in the temporal lobe for both hemisphere and in the precuneus and occipital regions only for the left hemisphere.

  1. The cytosolic chloride concentration in macula densa and cortical thick ascending limb cells.

    Science.gov (United States)

    Salomonsson, M; Gonzalez, E; Kornfeld, M; Persson, A E

    1993-03-01

    It is believed that chloride transport through the macula densa (MD) cells is a factor involved in the tubuloglomerular feedback (TGF) mechanism and in MD-mediated renin release. In this study isolated and perfused rabbit kidney cortical thick ascending limb (cTAL) segments containing MD plaques and attached glomeruli were loaded with chloride (CL-sensitive) 6 methoxy-1-fluorophore (sulphanate-propyl) quinolinium (SPQ). MD and cTAL intracellular chloride concentration ([Cl-]i) was determined by using image-intensified video microscopy and digital image-processing for measuring the intensity of the emitted SPQ fluorescence. With 150 mM NaCl in lumen and bath the [Cl-]i in MD and cTAL cells was 58.8 +/- 7.2 mM (n = 20) and 68.7 +/- 9.8 mM (n = 14), respectively. When the presumed luminal Na(+)-2Cl(-)-K+ co-transporter was blocked by adding 10(-4)M furosemide, the [Cl-]i was reduced in both, MD and cTAL cells from 55.5 +/- 11.9 to 28.6 +/- 10.0 mM (n = 10) and from 43.8 +/- 2.6 to 13.1 +/- 4.5 mM (n = 5), respectively. A reduction in luminal NaCl from 150 to 30 mM also decreased both, MD and cTAL [Cl-]i from 69.4 +/- 9.1 to 36.5 +/- 5.1 mM (n = 9) and from 82.9 +/- 14.5 to 49.4 +/- 8.0 mM (n = 8), respectively. Basolateral addition of the Cl(-)-channel blocker NPPB increased MD [Cl-]i from 31.1 +/- 2.0 to 100.7 +/- 17.0 mM (n = 5) and cTAL [Cl-]i from 44.4 +/- 12.9 to 89.7 +/- 11.7 mM (n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Comparison of cortical bone measurements between pQCT and HR-pQCT.

    Science.gov (United States)

    Lala, Deena; Cheung, Angela M; Gordon, Chris; Giangregorio, Lora

    2012-01-01

    The primary purpose of this study was to determine the accuracy of tibial cortical thickness measurements derived from peripheral quantitative computed tomography (pQCT) with analysis based on the circular ring model, using high-resolution peripheral quantitative computed tomography (HR-pQCT) (isotopic voxel size of 82 μm) as a gold standard. The secondary objective was to evaluate whether the accuracy of the pQCT-based estimates of cortical thickness (CTh), cortical area (CoA), cortical density (CDen), and total area (TotA) improve with alterations of voxel size from the standard 0.5-0.2mm. Fifteen dry tibia specimens were immersed in saline in a sealed cylinder and scanned 22.5mm from the distal tibia plateau using pQCT and HR-pQCT. pQCT yielded higher values for CTh and CDen and lower values for CoA. The differences between imaging techniques increased as the average CTh increased. No systematic bias was observed for CDen, CoA, and TotA. Similar differences were found between pQCT with voxel size 0.2mm and HR-pQCT. Significant correlations were observed for CTh (R=0.97, p ≤ 0.0001), CDen (R=0.99, p ≤ 0.0001), CoA (R=0.98, p ≤ 0.0001), and TotA (R=1.0, p ≤ 0.0001) when pQCT- and HR-pQCT-derived values were compared irrespective of which voxel size was used. Measurement variability between the imaging techniques was evident. Future studies aimed at examining cortical structure with pQCT should note that there are differences between the 2 techniques. Copyright © 2012 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  3. Development of new criteria for cortical bone histomorphometry in femoral neck: intra- and inter-observer reproducibility.

    Science.gov (United States)

    Tong, Xiao-Yu; Malo, Markus; Tamminen, Inari S; Isaksson, Hanna; Jurvelin, Jukka S; Kröger, Heikki

    2015-01-01

    Histomorphometry is commonly applied to study bone remodeling. Histological definitions of cortical bone boundaries have not been consistent. In this study, new criteria for specific definition of the transitional zone between the cortical and cancellous bone in the femoral neck were developed. The intra- and inter-observer reproducibility of this method was determined by quantitative histomorphometry and areal overlapping analysis. The undecalcified histological sections of femoral neck specimens (n = 6; from men aged 17-59 years) were processed and scanned to acquire histological images of complete bone sections. Specific criteria were applied to define histological boundaries. "Absolute cortex area" consisted of pure cortical bone tissue only, and was defined mainly based on the size of composite canals and their distance to an additional "guide" boundary (so-called "preliminary cortex boundary," the clear demarcation line of density between compact cortex and sparse trabeculae). Endocortical bone area was defined by recognizing characteristic endocortical structures adjacent to the preliminary cortical boundary. The present results suggested moderate to high reproducibility for low-magnification parameters (e.g., cortical bone area). The coefficient of variation (CV %) ranged from 0.02 to 5.61 in the intra-observer study and from 0.09 to 16.41 in the inter-observer study. However, the intra-observer reproducibility of some high-magnification parameters (e.g., osteoid perimeter/endocortical perimeter) was lower (CV %, 0.33-87.9). The overlapping of three histological areas in repeated analyses revealed highest intra- and inter-observer reproducibility for the absolute cortex area. This study provides specific criteria for the definition of histological boundaries for femoral neck bone specimens, which may aid more precise cortical bone histomorphometry.

  4. Effect of weight-bearing exercise and calcium supplement on cortical and trabecular bone in the proximal tibia metaphyseal- an experimental protocol in ovariectomized rats

    Directory of Open Access Journals (Sweden)

    Valliollah Dabidy Roshan1

    2009-01-01

    Full Text Available (Received 4 April, 2009; Accepted 17 June, 2009AbstractBackground and purpose: Osteoporotic fractures are much more common in older post-menopausal women and account for significant morbidity and mortality. Although age is an independent risk factor for fractures, bone micro-architecture is the predictor of subsequent fractures. Adequate calcium and Weight-bearing exercise are known to affect skeletal development, however, the effects of calcium supplement and treadmill endurance running on bone micro-architecture are not well known. The objective of this study was to determine the effects of treadmill endurance running training and calcium supplement, on micro-architectures of cortical and trabecular bone in the proximal tibia metaphyseal in ovariectomized Sprague Dawley rats.Materials and methods: Forty-three rats were randomly divided into endurance running training, calcium supplement, control, pre-test and base groups. The rats in the treadmill running group performed the progressive running exercise in 12 to 20 m/minutes for a total of 10 to 60 minutes, 5 times a week. Calcium group received ca supplement using Gavage (35 mg/kg/day for 8 weeks. After 8 weeks, micro-architecture parameters in the proximal tibia metaphyseal were measured by using a semi-automated image analysis system.Results: The ovariectomay was associated with a significant decrease in the trabecular volume and thickness, while separation insignificantly decreased in the cortical volume and thickness in the proximal tibia metaphyseal. The treadmill running exercise and calcium supplement significantly increased cortical or trabecular volume and also thickness and the trabecular separation compared with age-matched controls. Furthermore, the micro-architectures of cortical and trabecular bone in the proximal tibia metaphyseal was insignificant between the treadmill endurance running and calcium supplement groups.Conclusion: Skeletal benefits can be obtained by changes in

  5. Remodeling of heat-treated cortical bone allografts for posterior lumbar interbody fusion: serial 10-year follow-up.

    Science.gov (United States)

    Muramatsu, Koichi; Hachiya, Yudo; Izawa, Hiroyuki; Yamada, Harumoto

    2012-12-01

    We have selected heat-treated bone allografts as the graft material since the Tokai Bone Bank, the first regional bone bank in Japan, was established in 1992. In this study, we examined changes in bone mineral density (BMD), and morphology observed by magnetic resonance imaging (MRI), and histological findings of bone grafts in cases followed up for 7-10 years after bone grafting to grasp the remodeling of heat-treated cortical bone allografts for posterior lumber interbody fusion (PLIF). BMD of bone grafts was reduced by half at 10 years after grafting. MRI revealed that bone grafts were indistinguishable initially in only 22.2% of cases, whereas after a lengthy period of 10 years distinguishable in many cases. Histologically, new bone formation at the graft-host interface was observed earlier, at 1 year after grafting, than that at the periphery of canals in the specimens. The laminated structure of the cortical bone eroded over time, and fragmented bone trabeculae were observed in the specimens at 8 years or longer after grafting, though necrotic bone still remained in some sites.

  6. Magnetization transfer contrast imaging in bovine and human cortical bone applying an ultrashort echo time sequence at 3 Tesla.

    Science.gov (United States)

    Springer, Fabian; Martirosian, Petros; Machann, Jürgen; Schwenzer, Nina F; Claussen, Claus D; Schick, Fritz

    2009-05-01

    Magnetization transfer (MT) contrast imaging reveals interactions between free water molecules and macromolecules in a variety of tissues. The introduction of ultrashort echo time (UTE) sequences to clinical whole-body MR scanners expands the possibility of MT imaging to tissues with extremely fast signal decay such as cortical bone. The aim of this study was to investigate the MT effect of bovine cortical bone in vitro on a 3 Tesla whole-body MR unit. A 3D-UTE sequence with a rectangular-shaped on-resonant excitation pulse and a Gaussian-shaped off-resonant saturation pulse for MT preparation was applied. The flip angle and off-resonance frequency of the MT pulse was systematically varied. Measurements on various samples of bovine cortical bone, agar gel, aqueous manganese chloride solutions, and solid polymeric materials (polyurethane) were performed, followed by preliminary applications on human tibial bone in vivo. Direct on-resonant saturation effects of the MT prepulses were calculated numerically by means of Bloch's equations. Corrected for direct saturation effects dry and fresh bovine cortical bone showed "true" MTR values of 0.26 and 0.21, respectively. In vivo data were obtained from three healthy subjects and showed MTR values of 0.30 +/- 0.08. In vivo studies into MT of cortical bone might have the potential to give new insights in musculoskeletal pathologies.

  7. Glycation of human cortical and cancellous bone captures differences in the formation of Maillard reaction products between glucose and ribose.

    Science.gov (United States)

    Sroga, Grażyna E; Siddula, Alankrita; Vashishth, Deepak

    2015-01-01

    To better understand some aspects of bone matrix glycation, we used an in vitro glycation approach. Within two weeks, our glycation procedures led to the formation of advanced glycation end products (AGEs) at the levels that corresponded to approx. 25-30 years of the natural in vivo glycation. Cortical and cancellous bones from human tibias were glycated in vitro using either glucose (glucosylation) or ribose (ribosylation). Both glucosylation and ribosylation led to the formation of higher levels of AGEs and pentosidine (PEN) in cancellous than cortical bone dissected from all tested donors (young, middle-age and elderly men and women). More efficient glycation of bone matrix proteins in cancellous bone most likely depended on the higher porosity of this tissue, which facilitated better accessibility of the sugars to the matrix proteins. Notably, glycation of cortical bone from older donors led to much higher AGEs levels as compared to young donors. Such efficient in vitro glycation of older cortical bone could result from aging-related increase in porosity caused by the loss of mineral content. In addition, more pronounced glycation in vivo would be driven by elevated oxidation processes. Interestingly, the levels of PEN formation differed pronouncedly between glucosylation and ribosylation. Ribosylation generated very high levels of PEN (approx. 6- vs. 2.5-fold higher PEN level than in glucosylated samples). Kinetic studies of AGEs and PEN formation in human cortical and cancellous bone matrix confirmed higher accumulation of fluorescent crosslinks for ribosylation. Our results suggest that in vitro glycation of bone using glucose leads to the formation of lower levels of AGEs including PEN, whereas ribosylation appears to support a pathway toward PEN formation. Our studies may help to understand differences in the progression of bone pathologies related to protein glycation by different sugars, and raise awareness for excessive sugar supplementation in food and

  8. Correlation Between Bone and Soft Tissue Thickness in Maxillary Anterior Teeth

    Directory of Open Access Journals (Sweden)

    Nasrin Esfahanizadeh

    2016-12-01

    Full Text Available Objectives: The purpose of this study was to determine buccal bone and soft tissue thicknesses and their correlation in the maxillary anterior region using cone beam computed tomography (CBCT.Materials and Methods: In this cross sectional study, 330 sound maxillary incisors in 60 patients with a mean age of 37.5 years were assessed by CBCT scans. For better visualization of soft tissue, patients were asked to use plastic retractors in order to retract their lips and cheeks away from the gingival tissue before taking the scans. Measurements were made in three different positions: at the crest and at 2 and 5mm apical to the crest. The cementoenamel junction‒crest distance was measured. for data analyses, the Pearson’s correlation coefficient, ANOVA and intraclass correlation coefficient were used.Results: There were mildly significant linear associations between labial soft tissue and bone thickness in the canines and incisors (r<0.40, P<0.05, but no association was found for the lateral incisors. The mean thickness of buccal bone differed significantly in the maxillary anterior teeth, being greater for the lateral incisors (P<0.05. For soft tissue thickness, the results were the same, and the least thickness was recorded for the canines. There was a mild association between labial soft tissue and bone thickness in canines and incisors (r=0.2, P=0.3, but no such linear association was seen for the lateral incisors.Conclusions: The mean thickness of buccal bone and soft tissue in the anterior maxilla was <1mm and there was a mild linear correlation between them.Keywords: Facial Bones; Cone-Beam Computed Tomography; Maxilla; Esthetics, Dental

  9. Selective laser melting-produced porous titanium scaffolds regenerate bone in critical size cortical bone defects.

    Science.gov (United States)

    Van der Stok, Johan; Van der Jagt, Olav P; Amin Yavari, Saber; De Haas, Mirthe F P; Waarsing, Jan H; Jahr, Holger; Van Lieshout, Esther M M; Patka, Peter; Verhaar, Jan A N; Zadpoor, Amir A; Weinans, Harrie

    2013-05-01

    Porous titanium scaffolds have good mechanical properties that make them an interesting bone substitute material for large bone defects. These scaffolds can be produced with selective laser melting, which has the advantage of tailoring the structure's architecture. Reducing the strut size reduces the stiffness of the structure and may have a positive effect on bone formation. Two scaffolds with struts of 120-µm (titanium-120) or 230-µm (titanium-230) were studied in a load-bearing critical femoral bone defect in rats. The defect was stabilized with an internal plate and treated with titanium-120, titanium-230, or left empty. In vivo micro-CT scans at 4, 8, and 12 weeks showed more bone in the defects treated with scaffolds. Finally, 18.4 ± 7.1 mm(3) (titanium-120, p = 0.015) and 18.7 ± 8.0 mm(3) (titanium-230, p = 0.012) of bone was formed in those defects, significantly more than in the empty defects (5.8 ± 5.1 mm(3) ). Bending tests on the excised femurs after 12 weeks showed that the fusion strength reached 62% (titanium-120) and 45% (titanium-230) of the intact contralateral femurs, but there was no significant difference between the two scaffolds. This study showed that in addition to adequate mechanical support, porous titanium scaffolds facilitate bone formation, which results in high mechanical integrity of the treated large bone defects.

  10. Antiretroviral therapy and pregnancy: effect on cortical bone status of HIV-infected women

    Directory of Open Access Journals (Sweden)

    V Giacomet

    2012-11-01

    Full Text Available Purpose of the study: Vertical transmission of HIV can be almost eliminated by an appropriate combination of preventative measures, which include the use of combination antiretroviral therapy (ARV during pregnancy, elective cesarean delivery, and avoidance of breastfeeding. Although current ARV demonstrated to be very effective to control virus infection, it has numerous side effects, including negative repercussions on bone mass. Currently there are no data regarding the bone status of HIV-infected women who received ARV during pregnancy. The aim of this study was to evaluate cortical bone status at delivery in a group of HIV-infected women who received ARV during pregnancy, to monitor the changes occurring during the first year post-partum and to compare the results with those obtained in healthy mothers. Methods: We studied 17 HIV-infected and 55 HIV-uninfected healthy women within 3 days from delivery, at 4 and 12 months postpartum (median age 36.4 years. The majority (68% of the HIV-infected mothers was on ARV containing two nucleoside reverse transcriptase inhibitors (NRTI and a protease inhibitor (PI, and 16% was on a regimen containing two NRTIs and two PIs. Other ARV regimens included the use of two NRTIs and one non-NRTI (10%, one NRTI plus one PI (3%, or two NRTIs and three PIs (3%. The median (range exposure to ARV during gestation was 14 (5-35 weeks. The great majority (91% of the women showed an undetectable viral load (<50 cp/mL at delivery. Median CD4 number at delivery was 610 (128 to 1415. Cortical bone status was evaluated by quantitative ultrasonography at the mid-tibia, and bone measurements were expressed as the speed-of-sound (SOS. Summary of results: HIV-infected women after delivery had a median SOS of 3985 (3567–4242 m/s, while the median SOS of healthy women was 4025 (3643–4250. The difference was not significant (t=0.39; P=0.69. SOS measurements at baseline, at 4, and at 12 months are shown in Table 1. SOS values

  11. Hydration and radiation effects on the residual stress state of cortical bone.

    Science.gov (United States)

    Tung, Patrick K M; Mudie, Stephen; Daniels, John E

    2013-12-01

    The change in the biaxial residual stress state of hydroxyapatite crystals and collagen fibrillar structure in sections of bovine cortical bone has been investigated as a function of dehydration and radiation dose using combined small- and wide-angle X-ray scattering. It is shown that dehydration of the bone has a pronounced effect on the residual stress state of the crystalline phase, while the impact of radiation damage alone is less dramatic. In the initial hydrated state, a biaxial compressive stress of approximately -150 MPa along the bone axis exists in the hydroxyapatite crystals. As water evaporates from the bone material, the stress state moves to a tensile state of approximately 100 MPa. The collagen fibrillar structure is initially in a tensile residual stress state when the bone is hydrated and the state increases in magnitude slightly with dehydration. Radiation dose in continually hydrated samples also reduces the initial biaxial compressive stress magnitude in the hydroxyapatite phase; however, the stress remains compressive. Radiation exposure alone does not appear to affect the stress state of the collagen fibrillar structure.

  12. Analysis of forces in conventional and ultrasonically assisted plane cutting of cortical bone.

    Science.gov (United States)

    Alam, Khurshid; Khan, Mushtaq; Silberschmidt, Vadim V

    2013-06-01

    Bone cutting is a well accepted but technically demanding surgical procedure in orthopaedics. A level of tool penetration force during cutting of bones has been the prime concern to surgeons, since it can produce unnecessary mechanical damage to surrounding tissues. Research in this area has been undertaken for many decades to find ways to minimise the cutting force. Cutting of bone with ultrasonic tools is a relatively new technique replacing conventional procedures in neuro-, dental and orthopaedic surgeries, due to its precision and safety. In this article, the level of forces produced during a chisel-like tool penetration in a fresh cortical bone is studied. The obtained force data are analysed for both conventional cutting and ultrasonically assisted cutting. Through a series of experiments, it was demonstrated that the depth of cut and parameters of ultrasonic oscillations affected the level of cutting force, the former being the main factor in both types of cutting. It was found that the tool penetration force was decreased with an increase in the ultrasonic frequency or amplitude and was not affected by the cutting speed. The rise in bone temperature was measured and was found to be insensitive to the level of cutting speed within the range used in this study.

  13. Cortical thickness and semantic fluency in Alzheimer's disease and mild cognitive impairment.

    Science.gov (United States)

    Eastman, Jennifer A; Hwang, Kristy S; Lazaris, Andreas; Chow, Nicole; Ramirez, Leslie; Babakchanian, Sona; Woo, Ellen; Thompson, Paul M; Apostolova, Liana G

    2013-01-01

    The hallmark of Alzheimer's disease (AD) is declarative memory loss, but deficits in semantic fluency are also observed. We assessed how semantic fluency relates to cortical atrophy to identify specific regions that play a role in the loss of access to semantic information. Whole-brain structural magnetic resonance imaging (MRI) data were analyzed from 9 Normal Control (NC)(M=76.7, SD=5.6), 40 Mild Cognitive Impairment (MCI) (M=74.4, SD=8.6), and 10 probable AD (M=72.4, SD=8.0) subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI). They all were administered the Category Fluency (CF) animals and vegetables tests. Poorer semantic fluency was associated with bilateral cortical atrophy of the inferior parietal lobule (Brodman areas (BA) 39 and 40) and BA 6, 8, and 9 in the frontal lobe, as well as BA 22 in the temporal lobe. More diffuse frontal associations were seen in the left hemisphere involving BA 9, 10, 32, 44, 45, and 46. Additional cortical atrophy was seen in the temporoparietal (BA 37) and the right parastriate (BA 19, 18) cortices. Associations were more diffuse for performance on vegetable fluency than animal fluency. The permutation-corrected map-wise significance for CF animals was pcorrected=0.01 for the left hemisphere, and pcorrected=0.06 for the right hemisphere. The permutation-corrected map-wise significance for CF vegetables was pcorrected=0.009 for the left hemisphere, and pcorrected=0.03 for the right hemisphere. These results demonstrate the profound effect of cortical atrophy on semantic fluency. Specifically, tapping into semantic knowledge involves the frontal lobe in addition to the language cortices of the temporoparietal region.

  14. Cortical thickness correlates of specific cognitive performance accounted for by the general factor of intelligence in healthy children aged 6 to 18.

    Science.gov (United States)

    Karama, Sherif; Colom, Roberto; Johnson, Wendy; Deary, Ian J; Haier, Richard; Waber, Deborah P; Lepage, Claude; Ganjavi, Hooman; Jung, Rex; Evans, Alan C

    2011-04-15

    Prevailing psychometric theories of intelligence posit that individual differences in cognitive performance are attributable to three main sources of variance: the general factor of intelligence (g), cognitive ability domains, and specific test requirements and idiosyncrasies. Cortical thickness has been previously associated with g. In the present study, we systematically analyzed associations between cortical thickness and cognitive performance with and without adjusting for the effects of g in a representative sample of children and adolescents (N=207, Mean age=11.8; SD=3.5; Range=6 to 18.3 years). Seven cognitive tests were included in a measurement model that identified three first-order factors (representing cognitive ability domains) and one second-order factor representing g. Residuals of the cognitive ability domain scores were computed to represent g-independent variance for the three domains and seven tests. Cognitive domain and individual test scores as well as residualized scores were regressed against cortical thickness, adjusting for age, gender and a proxy measure of brain volume. g and cognitive domain scores were positively correlated with cortical thickness in very similar areas across the brain. Adjusting for the effects of g eliminated associations of domain and test scores with cortical thickness. Within a psychometric framework, cortical thickness correlates of cognitive performance on complex tasks are well captured by g in this demographically representative sample.

  15. Preliminary findings of cortical thickness abnormalities in blast injured service members and their relationship to clinical findings.

    Science.gov (United States)

    Tate, D F; York, G E; Reid, M W; Cooper, D B; Jones, L; Robin, D A; Kennedy, J E; Lewis, J

    2014-03-01

    Though cortical abnormalities have been demonstrated in moderate and severe traumatic brain injured (TBI) patients, there have been no studies examining cortical changes following blast related mild TBI (mTBI). The purpose of this study was to determine the effects and functional relevance of blast mTBI on cortical thickness in a small cohort of carefully screened blast injured US Service Members (SM). Twelve SM with mTBI acquired through blast injury were compared to 11 demographically matched control SM without TBI. Both mTBI and control participants were active duty and had completed a combat deployment. Subjects underwent MRI examination and the T1 weighted anatomic images were processed using the FreeSurfer suite of tools. Cortical thickness maps were compared between groups and examined for relationships with time since injury (TSI). Utilizing a large database of functional imaging results (BrainMap), significant regions of interest (ROI) were used to determine the behavioral profiles most consistently associated with the specific ROI. In addition, clinical variables were examined as part of post-hoc analysis of functional relevance. Group comparisons controlling for age demonstrated several significant clusters of cortical thinning for the blast injured SM. After multiple comparisons correction (False Discovery Rate (FDR)), two left hemisphere clusters remained significant (left superior temporal (STG) and frontal (SFG) gyri). No clusters were significantly correlated with TSI after FDR correction. Behavioral analysis for the STG and SFG clusters demonstrated three significant behavioral/cognitive sub-domains, each associated with audition and language. Blast injured SMs demonstrated distinct areas of cortical thinning in the STG and SFG. These areas have been previously shown to be associated with audition and language. Post-hoc analyses of clinical records demonstrated significant abnormal audiology reports for the blast injured SM suggesting that the

  16. Irradiation conditions for fiber laser bonding of HAp-glass ceramics with bovine cortical bone.

    Science.gov (United States)

    Tadano, Shigeru; Yamada, Satoshi; Kanaoka, Masaru

    2014-01-01

    Orthopedic implants are widely used to repair bones and to replace articulating joint surfaces. It is important to develop an instantaneous technique for the direct bonding of bone and implant materials. The aim of this study was to develop a technique for the laser bonding of bone with an implant material like ceramics. Ceramic specimens (10 mm diameter and 1 mm thickness) were sintered with hydroxyapatite and MgO-Al2O3-SiO2 glass powders mixed in 40:60 wt% proportions. A small hole was bored at the center of a ceramic specimen. The ceramic specimen was positioned onto a bovine bone specimen and a 5 mm diameter area of the ceramic specimen was irradiated using a fiber laser beam (1070-1080 nm wavelength). As a result, the bone and the ceramic specimens bonded strongly under the irradiation conditions of a 400 W laser power and a 1.0 s exposure time. The maximum shear strength was 5.3 ± 2.3 N. A bonding substance that penetrated deeply into the bone specimen was generated around the hole in the ceramic specimen. On using the fiber laser, the ceramic specimen instantaneously bonded to the bone specimen. Further, the irradiation conditions required for the bonding were investigated.

  17. Vascular calcification is associated with cortical bone loss in chronic renal failure rats with and without ovariectomy: the calcification paradox.

    Science.gov (United States)

    De Schutter, Tineke M; Neven, Ellen; Persy, Veerle P; Behets, Geert J; Postnov, Andrei A; De Clerck, Nora M; D'Haese, Patrick C

    2011-01-01

    Increased bone loss has been associated with the development of vascular calcification in patients with chronic renal failure (CRF). In this study, the effect of impaired bone metabolism on aortic calcifications was investigated in uremic rats with or without ovariectomy. CRF was induced by administration of a 0.75% adenine/2.5% protein diet for 4 weeks. In one group, osteoporosis was induced by ovariectomy (CRF-OVX), while the other group underwent a sham-operation instead (CRF). A third group consisted of ovariectomized rats with normal renal function (OVX). At regular time intervals throughout the study, bone status and aortic calcifications were evaluated by in vivo micro-CT. At sacrifice after 6 weeks of CRF, bone histomorphometry was performed and vascular calcification was assessed by bulk calcium analysis and Von Kossa staining. Renal function was significantly impaired in the CRF-OVX and CRF groups. Trabecular bone loss was seen in all groups. In the CRF-OVX and CRF groups, trabecular bone density was restored after adenine withdrawal, which coincided with cortical bone loss and the development of medial calcifications in the aorta. No significant differences with regard to the degree of aortic calcifications were seen between the two CRF groups. Neither cortical bone loss nor calcifications were seen in the OVX group. Cortical bone loss significantly correlated with the severity of vascular calcification in the CRF-OVX and CRF groups, but no associations with trabecular bone changes were found. Cortical rather than trabecular bone loss is associated with the process of calcification in rats with adenine- induced CRF. Copyright © 2011 S. Karger AG, Basel.

  18. Novel anatomic adaptation of cortical bone to meet increased mineral demands of reproduction.

    Science.gov (United States)

    Macica, Carolyn M; King, Helen E; Wang, Meina; McEachon, Courtney L; Skinner, Catherine W; Tommasini, Steven M

    2016-04-01

    The goal of this study was to investigate the effects of reproductive adaptations to mineral homeostasis on the skeleton in a mouse model of compromised mineral homeostasis compared to adaptations in control, unaffected mice. During pregnancy, maternal adaptations to high mineral demand include more than doubling intestinal calcium absorption by increasing calcitriol production. However, calcitriol biosynthesis is impaired in HYP mice, a murine model of X-linked hypophosphatemia (XLH). In addition, there is a paucity of mineralized trabecular bone, a primary target of bone resorption during pregnancy and lactation. Because the highest density of mineral is in mature cortical bone, we hypothesized that mineral demand is met by utilizing intracortical mineral reserves. Indeed, analysis of HYP mice revealed dramatic increases in intracortical porosity characterized by elevated serum PTH and type-I collagen matrix-degrading enzyme MMP-13. We discovered an increase in carbonate ion substitution in the bone mineral matrix during pregnancy and lactation of HYP mice, suggesting an alternative mechanism of bone remodeling that maintains maternal bone mass during periods of high mineral demand. This phenomenon is not restricted to XLH, as increased carbonate in the mineral matrix also occurred in wild-type mice during lactation. Taken together, these data suggest that increased intracortical perilacunar mineral turnover also contributes to maintaining phosphate levels during periods of high mineral demand. Understanding the mechanisms of skeletal contribution to mineral homeostasis is important to improving the treatment and prevention of fracture risk and bone fragility for female patients with XLH, but also provides important insight into the role and unique adaptations of the maternal skeleton to the demands of fetal development and the needs of postnatal nutrition. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Neonatal pain-related stress predicts cortical thickness at age 7 years in children born very preterm.

    Directory of Open Access Journals (Sweden)

    Manon Ranger

    Full Text Available BACKGROUND: Altered brain development is evident in children born very preterm (24-32 weeks gestational age, including reduction in gray and white matter volumes, and thinner cortex, from infancy to adolescence compared to term-born peers. However, many questions remain regarding the etiology. Infants born very preterm are exposed to repeated procedural pain-related stress during a period of very rapid brain development. In this vulnerable population, we have previously found that neonatal pain-related stress is associated with atypical brain development from birth to term-equivalent age. Our present aim was to evaluate whether neonatal pain-related stress (adjusted for clinical confounders of prematurity is associated with altered cortical thickness in very preterm children at school age. METHODS: 42 right-handed children born very preterm (24-32 weeks gestational age followed longitudinally from birth underwent 3-D T1 MRI neuroimaging at mean age 7.9 yrs. Children with severe brain injury and major motor/sensory/cognitive impairment were excluded. Regional cortical thickness was calculated using custom developed software utilizing FreeSurfer segmentation data. The association between neonatal pain-related stress (defined as the number of skin-breaking procedures accounting for clinical confounders (gestational age, illness severity, infection, mechanical ventilation, surgeries, and morphine exposure, was examined in relation to cortical thickness using constrained principal component analysis followed by generalized linear modeling. RESULTS: After correcting for multiple comparisons and adjusting for neonatal clinical factors, greater neonatal pain-related stress was associated with significantly thinner cortex in 21/66 cerebral regions (p-values ranged from 0.00001 to 0.014, predominately in the frontal and parietal lobes. CONCLUSIONS: In very preterm children without major sensory, motor or cognitive impairments, neonatal pain-related stress

  20. Longitudinal MRI study of cortical thickness, perfusion, and metabolite levels in major depressive disorder

    DEFF Research Database (Denmark)

    Järnum, Hanna; Eskildsen, Simon Fristed; Steffensen, Elena G

    2011-01-01

    disorder (MDD) display morphologic, functional, and metabolic brain abnormalities in limbic-cortical regions at a baseline magnetic resonance (MR) scan and whether these changes are normalized in MDD patients in remission at a follow-up scan. Method:  A longitudinal 3.0-Tesla (T) magnetic resonance imaging...

  1. Longitudinal MRI study of cortical thickness, perfusion, and metabolite levels in major depressive disorder

    DEFF Research Database (Denmark)

    Järnum, Hanna; Eskildsen, Simon Fristed; Steffensen, Elena G;

    2011-01-01

    disorder (MDD) display morphologic, functional, and metabolic brain abnormalities in limbic-cortical regions at a baseline magnetic resonance (MR) scan and whether these changes are normalized in MDD patients in remission at a follow-up scan. Method:  A longitudinal 3.0-Tesla (T) magnetic resonance imaging...

  2. Elastic modulus and hardness of cortical and trabecular bovine bone measured by nanoindentation

    Institute of Scientific and Technical Information of China (English)

    WANG X J; CHEN X B; HODGSON P D; WEN C E

    2006-01-01

    The elastic modulus and hardness of several microstructure components of dry bovine vertebrae and tibia have been investigated in the longitude and transverse directions using nanoindentation. The elastic modulus for the osteons and the interstitial lamellae in the longitude direction were found to be (24.7±2.5) GPa and (30.1±2.4) GPa. As it's difficult to distinguish osteons from interstitial lamellae in the transverse direction,the average elastic modulus for cortical bovine bone in the transverse direction was (19.8±1.6) GPa. The elastic modulus for trabecular bone in the longitude and transverse direction were (20±2) GPa and (14.7±1.9) GPa respectively. The hardness also varied among the microstructure components in the range of 0.41-0.89 GPa. Analyses of variance show that the values are significantly different.

  3. In vitro ultrasonic and mechanic characterization of the modulus of elasticity of children cortical bone.

    Science.gov (United States)

    Berteau, Jean-Philippe; Baron, Cécile; Pithioux, Martine; Launay, Franck; Chabrand, Patrick; Lasaygues, Philippe

    2014-07-01

    The assessment of elastic properties in children's cortical bone is a major challenge for biomechanical engineering community, more widely for health care professionals. Even with classical clinical modalities such as X-ray tomography, MRI, and/or echography, inappropriate diagnosis can result from the lack of reference values for children bone. This study provides values for elastic properties of cortical bone in children using ultrasonic and mechanical measurements, and compares them with adult values. 18 fibula samples from 8 children (5-16 years old, mean age 10.6 years old ±4.4) were compared to 16 fibula samples from 3 elderly adults (more than 65 years old). First, the dynamic modulus of elasticity (Edyn) and Poisson's ratio (ν) are evaluated via an ultrasonic method. Second, the static modulus of elasticity (Esta) is estimated from a 3-point microbending test. The mean values of longitudinal and transverse wave velocities measured at 10 MHz for the children's samples are respectively 3.2mm/μs (±0.5) and 1.8mm/μs (±0.1); for the elderly adults' samples, velocities are respectively 3.5mm/μs (±0.2) and 1.9 mm/μs (±0.09). The mean Edyn and the mean Esta for the children's samples are respectively 15.5 GPa (±3.4) and 9.1 GPa (±3.5); for the elderly adults' samples, they are respectively 16.7 GPa (±1.9) and 5.8 GPa (±2.1). Edyn, ν and Esta are in the same range for children's and elderly adults' bone without any parametric statistical difference; a ranking correlation between Edyn and Esta is shown for the first time.

  4. Organ and tissue level properties are more sensitive to age than osteocyte lacunar characteristics in rat cortical bone

    DEFF Research Database (Denmark)

    Wittig, Nina; Bach-Gansmo, Fiona Linnea; Birkbak, Mie Elholm

    2016-01-01

    lacunar properties in rat cortical bone. Femora of 14 to 42-week-old female Wistar rats were investigated using multiple complementary techniques including X-ray micro-computed tomography and biomechanical testing. The body weight, femoral length, aBMD, load to fracture, tissue volume, bone volume......, and tissue density were found to increase rapidly with age at 14–30 weeks. At the age of 30–42 weeks, the growth rate appeared to decrease. However, no accompanying changes were found in osteocyte lacunar properties such as lacunar volume, ellipsoidal radii, lacunar stretch, lacunar oblateness, or lacunar...... orientation with animal age. Hence, the evolution of organ and tissue level properties with age in rat cortical bone is not accompanied by related changes in osteocyte lacunar properties. This suggests that bone microstructure and bone matrix material properties and not the geometric properties...

  5. A novel composite material specifically developed for ultrasound bone phantoms: cortical, trabecular and skull.

    Science.gov (United States)

    Wydra, A; Maev, R Gr

    2013-11-21

    In the various stages of developing diagnostic and therapeutic equipment, the use of phantoms can play a very important role in improving the process, help in implementation, testing and calibrations. Phantoms are especially useful in developing new applications and training new doctors in medical schools. However, devices that use different physical factors, such as MRI, Ultrasound, CT Scan, etc will require the phantom to be made of different physical properties. In this paper we introduce the properties of recently designed new materials for developing phantoms for ultrasonic human body investigation, which in today's market make up more than 30% in the world of phantoms. We developed a novel composite material which allows fabrication of various kinds of ultrasound bone phantoms to mimic most of the acoustical properties of human bones. In contrast to the ex vivo tissues, the proposed material can maintain the physical and acoustical properties unchanged for long periods of time; moreover, these properties can be custom designed and created to suit specific needs. As a result, we introduce three examples of ultrasound phantoms that we manufactured in our laboratory: cortical, trabecular and skull bone phantoms. The paper also presents the results of a comparison study between the acoustical and physical properties of actual human bones (reported in the referenced literatures) and the phantoms manufactured by us.

  6. Geometric-attributes-based segmentation of cortical bone slides using optimized neural networks.

    Science.gov (United States)

    Hage, Ilige S; Hamade, Ramsey F

    2016-05-01

    In cortical bone, solid (lamellar and interstitial) matrix occupies space left over by porous microfeatures such as Haversian canals, lacunae, and canaliculi-containing clusters. In this work, pulse-coupled neural networks (PCNN) were used to automatically distinguish the microfeatures present in histology slides of cortical bone. The networks' parameters were optimized using particle swarm optimization (PSO). When forming the fitness functions for the PSO, we considered the microfeatures' geometric attributes-namely, their size (based on measures of elliptical perimeter or area), shape (based on measures of compactness or the ratio of minor axis length to major axis length), and a two-way combination of these two geometric attributes. This hybrid PCNN-PSO method was further enhanced for pulse evaluation by combination with yet another method, adaptive threshold (AT), where the PCNN algorithm is repeated until the best threshold is found corresponding to the maximum variance between two segmented regions. Together, this framework of using PCNN-PSO-AT constitutes, we believe, a novel framework in biomedical imaging. Using this framework and extracting microfeatures from only one training image, we successfully extracted microfeatures from other test images. The high fidelity of all resultant segments was established using quantitative metrics such as precision, specificity, and Dice indices.

  7. Comparison of mechanical and ultrasound elastic modulus of ovine tibial cortical bone.

    Science.gov (United States)

    Grant, Caroline A; Wilson, Lance J; Langton, Christian; Epari, Devakar

    2014-07-01

    Finite element models of bones can be created by deriving geometry from an X-ray CT scan. Material properties such as the elastic modulus can then be applied using either a single or set of homogeneous values, or individual elements can have local values mapped onto them. Values for the elastic modulus can be derived from the CT density values using an elasticity versus density relationship. Many elasticity-density relationships have been reported in the literature for human bone. However, while ovine in vivo models are common in orthopaedic research, no work has been done to date on creating FE models of ovine bones. To create these models and apply relevant material properties, an ovine elasticity-density relationship needs to be determined. Using fresh frozen ovine tibias the apparent density of regions of interest was determined from a clinical CT scan. The bones were the sectioned into cuboid samples of cortical bone from the regions of interest. Ultrasound was used to determine the elastic modulus in each of three directions - longitudinally, radially and tangentially. Samples then underwent traditional compression testing in each direction. The relationships between apparent density and both ultrasound, and compression modulus in each direction were determined. Ultrasound testing was found to be a highly repeatable non-destructive method of calculating the elastic modulus, particularly suited to samples of this size. The elasticity-density relationships determined in the longitudinal direction were very similar between the compression and ultrasound data over the density range examined. A clear difference was seen in the elastic modulus between the longitudinal and transverse directions of the bone samples, and a transverse elasticity-density relationship is also reported.

  8. Individual-specific multi-scale finite element simulation of cortical bone of human proximal femur

    Energy Technology Data Exchange (ETDEWEB)

    Ascenzi, Maria-Grazia, E-mail: mgascenzi@mednet.ucla.edu [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States); Kawas, Neal P., E-mail: nealkawas@ucla.edu [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States); Lutz, Andre, E-mail: andre.lutz@hotmail.de [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany); Kardas, Dieter, E-mail: kardas@ibnm.uni-hannover.de [ContiTech Vibration Control, Jaedekamp 30 None, 30419 Hannover (Germany); Nackenhorst, Udo, E-mail: nackenhorst@ibnm.uni-hannover.de [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany); Keyak, Joyce H., E-mail: jhkeyak@uci.edu [Department of Radiological Sciences, Medical Sciences I, Bldg 811, Room B140, University of California, Irvine, CA 92697-5000 (United States)

    2013-07-01

    We present an innovative method to perform multi-scale finite element analyses of the cortical component of the femur using the individual’s (1) computed tomography scan; and (2) a bone specimen obtained in conjunction with orthopedic surgery. The method enables study of micro-structural characteristics regulating strains and stresses under physiological loading conditions. The analysis of the micro-structural scenarios that cause variation of strain and stress is the first step in understanding the elevated strains and stresses in bone tissue, which are indicative of higher likelihood of micro-crack formation in bone, implicated in consequent remodeling or macroscopic bone fracture. Evidence that micro-structure varies with clinical history and contributes in significant, but poorly understood, ways to bone function, motivates the method’s development, as does need for software tools to investigate relationships between macroscopic loading and micro-structure. Three applications – varying region of interest, bone mineral density, and orientation of collagen type I, illustrate the method. We show, in comparison between physiological loading and simple compression of a patient’s femur, that strains computed at the multi-scale model’s micro-level: (i) differ; and (ii) depend on local collagen-apatite orientation and degree of calcification. Our findings confirm the strain concentration role of osteocyte lacunae, important for mechano-transduction. We hypothesize occurrence of micro-crack formation, leading either to remodeling or macroscopic fracture, when the computed strains exceed the elastic range observed in micro-structural testing.

  9. Computational Study of the Effect of Cortical Porosity on Ultrasound Wave Propagation in Healthy and Osteoporotic Long Bones

    Directory of Open Access Journals (Sweden)

    Vassiliki T. Potsika

    2016-03-01

    Full Text Available Computational studies on the evaluation of bone status in cases of pathologies have gained significant interest in recent years. This work presents a parametric and systematic numerical study on ultrasound propagation in cortical bone models to investigate the effect of changes in cortical porosity and the occurrence of large basic multicellular units, simply called non-refilled resorption lacunae (RL, on the velocity of the first arriving signal (FAS. Two-dimensional geometries of cortical bone are established for various microstructural models mimicking normal and pathological tissue states. Emphasis is given on the detection of RL formation which may provoke the thinning of the cortical cortex and the increase of porosity at a later stage of the disease. The central excitation frequencies 0.5 and 1 MHz are examined. The proposed configuration consists of one point source and multiple successive receivers in order to calculate the FAS velocity in small propagation paths (local velocity and derive a variation profile along the cortical surface. It was shown that: (a the local FAS velocity can capture porosity changes including the occurrence of RL with different number, size and depth of formation; and (b the excitation frequency 0.5 MHz is more sensitive for the assessment of cortical microstructure.

  10. [Olpadronate prevents cortical and trabecular bone loss induced by supraphysiological dosis of thyroxine in ovariectomized rats].

    Science.gov (United States)

    Zeni, S N; Gómez Acotto, C; Di Gregorio, S

    1998-01-01

    The aim of the present report was to clarify the effect of excess T4 on axial and peripheral bone mineral density (BMD) in estrogen-depleted rats. The protective effect of olpadronate (Olpa) on axial and peripheral bone mass in thyroxine-treated rats was also investigated. Female Sprague-Dawley rats were used: SHAM, OVX + Vh, OVX + Olpa (0.3 mg/kg/week), OVX + T4 (250 micrograms/kg/day) and OVX + T4 + Olpa rats. OVX + Vh group presented a BMD lower than SHAM in the tibia (p < 0.01) but not in femur or lumbar spine; the middle tibia BMD did not change but it was lower at the distal (pns.) and proximal levels (p < 0.003) in OVX + Vh. OVX + T4 rats presented a BMD significantly lower than OVX + Vh rats in total tibia (p < 0.02), femur (p < 0.006) and lumbar spine (p < 0.006). Moreover the BMD was lower in all studied areas of the tibia, but it was statistically significant only at the middle level (p < 0.004). OVX + Olpa rats had a BMD higher than OVX + Vh rats in femur (p < 0.002), lumbar spine (p < 0.0001), total (p < 0.001) and proximal tibia (p < 0.001). Surprisingly, total and proximal tibia BMD values in OVX + Olpa rats presented a BMD significantly higher than OVX + T4 rats in femur (p < 0.001), lumbar spine (p < 0.001), tibia (p < 0.001) and proximal tibia (p < 0.0001). It is important to point out that OVX + T4 + Olpa BMD was significantly higher than in SHAM rats at the lumbar spine, total and proximal tibia (p < 0.01). The present study suggests that although supraphysiological thyroid hormone affected both cortical and trabecular bone, under estrogen-depleted conditions, the cortical bone appears to be more sensitive than the trabecular bone to T4 treatment. We also found that Olpa could prevent the peripheral and axial bone loss induced by thyroid hormone excess.

  11. Comparison of grey matter volume and thickness for analysing cortical changes in chronic schizophrenia: a matter of surface area, grey/white matter intensity contrast, and curvature.

    Science.gov (United States)

    Kong, Li; Herold, Christina J; Zöllner, Frank; Salat, David H; Lässer, Marc M; Schmid, Lena A; Fellhauer, Iven; Thomann, Philipp A; Essig, Marco; Schad, Lothar R; Erickson, Kirk I; Schröder, Johannes

    2015-02-28

    Grey matter volume and cortical thickness are the two most widely used measures for detecting grey matter morphometric changes in various diseases such as schizophrenia. However, these two measures only share partial overlapping regions in identifying morphometric changes. Few studies have investigated the contributions of the potential factors to the differences of grey matter volume and cortical thickness. To investigate this question, 3T magnetic resonance images from 22 patients with schizophrenia and 20 well-matched healthy controls were chosen for analyses. Grey matter volume and cortical thickness were measured by VBM and Freesurfer. Grey matter volume results were then rendered onto the surface template of Freesurfer to compare the differences from cortical thickness in anatomical locations. Discrepancy regions of the grey matter volume and thickness where grey matter volume significantly decreased but without corresponding evidence of cortical thinning involved the rostral middle frontal, precentral, lateral occipital and superior frontal gyri. Subsequent region-of-interest analysis demonstrated that changes in surface area, grey/white matter intensity contrast and curvature accounted for the discrepancies. Our results suggest that the differences between grey matter volume and thickness could be jointly driven by surface area, grey/white matter intensity contrast and curvature.

  12. Mapping cortical thickness of the patients with unilateral end-stage open angle glaucoma on planar cerebral cortex maps.

    Directory of Open Access Journals (Sweden)

    Piotr Bogorodzki

    Full Text Available PURPOSE: To estimate and compare cerebral cortex thickness in patients with unilateral end-stage glaucoma with that of age-matched individuals with unaffected vision. METHODS: 14 patients with unilateral end-stage primary open angle glaucoma (POAG and 12 age-matched control individuals with no problems with vision were selected for the study based on detailed ophthalmic examination. For each participant 3D high-resolution structural brain T1-weighted magnetization prepared MR images were acquired on a 3.0 T scanner. Brain cortex thickness was estimated using the FreeSurfer image analysis environment. After warping of subjects' cortical surfaces to FreeSurfer common space, differences between POAG and control groups were inferred at the group analysis level with the General Linear Model. RESULTS: The analysis performed revealed local thinning in the visual cortex areas in the POAG group. Statistically significant differences form 600 mm2 clusters located in the Brodmann area BA19 in the left and right hemisphere. CONCLUSION: Unilateral vision loss due to end-stage neuropathy from POAG is associated with significant thinning of cortical areas employed in vision.

  13. Longitudinal development of frontoparietal activity during feedback learning: Contributions of age, performance, working memory and cortical thickness

    Directory of Open Access Journals (Sweden)

    Sabine Peters

    2016-06-01

    Full Text Available Feedback learning is a crucial skill for cognitive flexibility that continues to develop into adolescence, and is linked to neural activity within a frontoparietal network. Although it is well conceptualized that activity in the frontoparietal network changes during development, there is surprisingly little consensus about the direction of change. Using a longitudinal design (N = 208, 8–27 years, two measurements in two years, we investigated developmental trajectories in frontoparietal activity during feedback learning. Our first aim was to test for linear and nonlinear developmental trajectories in dorsolateral prefrontal cortex (DLPFC, superior parietal cortex (SPC, supplementary motor area (SMA and anterior cingulate cortex (ACC. Second, we tested which factors (task performance, working memory, cortical thickness explained additional variance in time-related changes in activity besides age. Developmental patterns for activity in DLPFC and SPC were best characterized by a quadratic age function leveling off/peaking in late adolescence. There was a linear increase in SMA and a linear decrease with age in ACC activity. In addition to age, task performance explained variance in DLPFC and SPC activity, whereas cortical thickness explained variance in SMA activity. Together, these findings provide a novel perspective of linear and nonlinear developmental changes in the frontoparietal network during feedback learning.

  14. Variations in the buccal-lingual alveolar bone thickness of impacted mandibular third molar: our classification and treatment perspectives.

    Science.gov (United States)

    Ge, Jing; Zheng, Jia-Wei; Yang, Chi; Qian, Wen-Tao

    2016-01-13

    Selecting either buccal or lingual approach for the mandibular third molar surgical extraction has been an intense debate for years. The aim of this observational retrospective study was to classify the molar based on the proximity to the external cortical bone, and analyze the position of inferior alveolar canal (IAC) of each type. Cone-beam CT (CBCT) data of 110 deeply impacted mandibular third molars from 91 consecutive patients were analyzed. A new classification based on the mean deduction value (MD) of buccal-lingual alveolar bone thickness was proposed: MD≥1 mm was classified as buccal position, 1 mm>MD>-1 mm was classified as central position, MD≤-1 mm was classified as lingual position. The study samples were distributed as: buccal position (1.8%) in 2 subjects, central position (10.9%) in 12 and lingual position (87.3%) in 96. Ninety-six molars (87.3%) contacted the IAC. The buccal and inferior IAC course were the most common types in impacted third molar, especially in lingually positioned ones. Our study suggested that amongst deeply impacted mandibular third molars, lingual position occupies the largest proportion, followed by the central, and then the buccal type.

  15. Histomorphometric Assessment of Cancellous and Cortical Bone Material Distribution in the Proximal Humerus of Normal and Osteoporotic Individuals: Significantly Reduced Bone Stock in the Metaphyseal and Subcapital Regions of Osteoporotic Individuals.

    Science.gov (United States)

    Sprecher, Christoph M; Schmidutz, Florian; Helfen, Tobias; Richards, R Geoff; Blauth, Michael; Milz, Stefan

    2015-12-01

    Osteoporosis is a systemic disorder predominantly affecting postmenopausal women but also men at an advanced age. Both genders may suffer from low-energy fractures of, for example, the proximal humerus when reduction of the bone stock or/and quality has occurred.The aim of the current study was to compare the amount of bone in typical fracture zones of the proximal humerus in osteoporotic and non-osteoporotic individuals.The amount of bone in the proximal humerus was determined histomorphometrically in frontal plane sections. The donor bones were allocated to normal and osteoporotic groups using the T-score from distal radius DXA measurements of the same extremities. The T-score evaluation was done according to WHO criteria. Regional thickness of the subchondral plate and the metaphyseal cortical bone were measured using interactive image analysis.At all measured locations the amount of cancellous bone was significantly lower in individuals from the osteoporotic group compared to the non-osteoporotic one. The osteoporotic group showed more significant differences between regions of the same bone than the non-osteoporotic group. In both groups the subchondral cancellous bone and the subchondral plate were least affected by bone loss. In contrast, the medial metaphyseal region in the osteoporotic group exhibited higher bone loss in comparison to the lateral side.This observation may explain prevailing fracture patterns, which frequently involve compression fractures and certainly has an influence on the stability of implants placed in this medial region. It should be considered when planning the anchoring of osteosynthesis materials in osteoporotic patients with fractures of the proximal humerus.

  16. Synchrotron ultraviolet microspectroscopy on rat cortical bone: involvement of tyrosine and tryptophan in the osteocyte and its environment.

    Directory of Open Access Journals (Sweden)

    Stéphane Pallu

    Full Text Available Alcohol induced osteoporosis is characterized by a bone mass decrease and microarchitecture alterations. Having observed an excess in osteocyte apoptosis, we aimed to assess the bone tissue biochemistry, particularly in the osteocyte and its environment. For this purpose, we used a model of alcohol induced osteoporosis in rats. Bone sections of cortical bone were investigated using synchrotron UV-microspectrofluorescence at subcellular resolution. We show that bone present three fluorescence peaks at 305, 333 and 385 nm, respectively corresponding to tyrosine, tryptophan and collagen. We have determined that tyrosine/collagen and tryptophan/collagen ratios were higher in the strong alcohol consumption group. Tryptophan is related to the serotonin metabolism involved in bone formation, while tyrosine is involved in the activity of tyrosine kinases and phosphatases in osteocytes. Our experiment represents the first combined synchrotron UV microspectroscopy analysis of bone tissue with a quantitative biochemical characterization in the osteocyte and surrounding matrix performed separately.

  17. A weighted osteon morphotype score outperforms regional osteon percent prevalence calculations for interpreting cortical bone adaptation.

    Science.gov (United States)

    Skedros, John G; Kiser, Casey J; Mendenhall, Shaun D

    2011-01-01

    Using circularly polarized light microscopy,we described a weighted-scoring method for quantifying regional distributions of six secondary osteon morphotypes(Skedros et al.: Bone 44 (2009) 392-403). This osteon morphotype score (MTS) strongly correlated with "tension" and "compression" cortices produced by habitual bending. In the present study, we hypothesized that the osteon MTS is superior to a relatively simpler method based on the percent prevalence (PP) of these osteon morphotypes. This was tested in proximal femoral diaphyses of adult chimpanzees and habitually bent bones: calcanei from sheep, deer, and horses, radii from sheep and horses, and third metacarpals (MC3s) from horses. Sheep tibiae were examined because their comparatively greater torsion/shear would not require regional variations in osteon morphotypes. Predominant collagen fiber orientation (CFO), a predictor of regionally prevalent/predominant strain mode, was quantified as image gray levels (birefringence). Ten PP calculations were conducted. Although PP calculations were similar to the osteon MTS in corroborating CFO differences between "tension" and "compression" cortices of the chimpanzee femora and most of the habitually bent bones, PP calculations failed to show a compression/tension difference in equine MC3s and sheep radii. With the exception of the prevalence of the "distributed" osteon morphotype, correlations of PP calculations with CFO were weak and/or negative. By contrast, the osteon MTS consistently showed positive correlations with predominant CFO. Compared with the osteon MTS and predominant CFO, regional variations in PP of osteon morpho types are not stronger predictors of nonuniform strain distributions produced by bending.

  18. Reduced cortical bone compositional heterogeneity with bisphosphonate treatment in postmenopausal women with intertrochanteric and subtrochanteric fractures.

    Science.gov (United States)

    Donnelly, Eve; Meredith, Dennis S; Nguyen, Joseph T; Gladnick, Brian P; Rebolledo, Brian J; Shaffer, Andre D; Lorich, Dean G; Lane, Joseph M; Boskey, Adele L

    2012-03-01

    Reduction of bone turnover with bisphosphonate treatment alters bone mineral and matrix properties. Our objective was to investigate the effect of bisphosphonate treatment on bone tissue properties near fragility fracture sites in the proximal femur in postmenopausal women with osteoporosis. The mineral and collagen properties of corticocancellous biopsies from the proximal femur were compared in bisphosphonate-naive (-BIS, n = 20) and bisphosphonate-treated (+BIS, n = 20, duration 7 ± 5 years) patients with intertrochanteric (IT) and subtrochanteric (ST) fractures using Fourier transform infrared imaging (FTIRI). The mean values of the FTIRI parameter distributions were similar across groups, but the widths of the parameter distributions tended to be reduced in the +BIS group relative to the -BIS group. Specifically, the widths of the cortical collagen maturity and crystallinity were reduced in the +BIS group relative to those of the -BIS group by 28% (+BIS 0.45 ± 0.18 versus -BIS 0.63 ± 0.28, p = 0.03) and 17% (+BIS 0.087 ± 0.012 versus -BIS 0.104 ± 0.036, p = 0.05), respectively. When the tissue properties were examined as a function of fracture morphology within the +BIS group, the FTIR parameters were generally similar regardless of fracture morphology. However, the cortical mineral:matrix ratio was 8% greater in tissue from patients with atypical ST fractures (n = 6) than that of patients with typical (IT or spiral ST) fractures (n = 14) (Atypical 5.6 ± 0.3 versus Typical 5.2 ± 0.5, p = 0.03). Thus, although the mean values of the FTIR properties were similar in both groups, the tissue in bisphosphonate-treated patients had a more uniform composition than that of bisphosphonate-naive patients. The observed reductions in mineral and matrix heterogeneity may diminish tissue-level toughening mechanisms.

  19. Non destructive characterization of cortical bone micro-damage by nonlinear resonant ultrasound spectroscopy.

    Directory of Open Access Journals (Sweden)

    Sylvain Haupert

    Full Text Available The objective of the study was to evaluate the ability of a nonlinear ultrasound technique, the so-called nonlinear resonant ultrasound spectroscopy (NRUS technique, for detecting early microdamage accumulation in cortical bone induced by four-point bending fatigue. Small parallelepiped beam-shaped human cortical bone specimens were subjected to cyclic four-point bending fatigue in several steps. The specimens were prepared to control damage localization during four-point bending fatigue cycling and to unambiguously identify resonant modes for NRUS measurements. NRUS measurements were achieved to follow the evolution of the nonlinear hysteretic elastic behavior during fatigue-induced damage. After each fatigue step, a small number of specimens was removed from the protocol and set apart to quantitatively assess the microcrack number density and length using synchrotron radiation micro-computed tomography (SR-µCT. The results showed a significant effect of damage steps on the nonlinear hysteretic elastic behavior. No significant change in the overall length of microcracks was observed in damaged regions compared to the load-free control regions. Only an increased number of shortest microcracks, those in the lowest quartile, was noticed. This was suggestive of newly formed microcracks during the early phases of damage accumulation. The variation of nonlinear hysteretic elastic behavior was significantly correlated to the variation of the density of short microcracks. Our results suggest that the nonlinear hysteretic elastic behavior is sensitive to early bone microdamage. Therefore NRUS technique can be used to monitor fatigue microdamage progression in in vitro experiments.

  20. Elastic moduli of untreated, demineralized and deproteinized cortical bone: validation of a theoretical model of bone as an interpenetrating composite material.

    Science.gov (United States)

    Hamed, E; Novitskaya, E; Li, J; Chen, P-Y; Jasiuk, I; McKittrick, J

    2012-03-01

    A theoretical experimentally based multi-scale model of the elastic response of cortical bone is presented. It portrays the hierarchical structure of bone as a composite with interpenetrating biopolymers (collagen and non-collagenous proteins) and minerals (hydroxyapatite), together with void spaces (porosity). The model involves a bottom-up approach and employs micromechanics and classical lamination theories of composite materials. Experiments on cortical bone samples from bovine femur include completely demineralized and deproteinized bones as well as untreated bone samples. Porosity and microstructure are characterized using optical and scanning electron microscopy, and micro-computed tomography. Compression testing is used to measure longitudinal and transverse elastic moduli of all three bone types. The characterization of structure and properties of these three bone states provides a deeper understanding of the contributions of the individual components of bone to its elastic response and allows fine tuning of modeling assumptions. Very good agreement is found between theoretical modeling and compression testing results, confirming the validity of the interpretation of bone as an interpenetrating composite material.

  1. Development of a Three-Dimensional (3D Printed Biodegradable Cage to Convert Morselized Corticocancellous Bone Chips into a Structured Cortical Bone Graft

    Directory of Open Access Journals (Sweden)

    Ying-Chao Chou

    2016-04-01

    Full Text Available This study aimed to develop a new biodegradable polymeric cage to convert corticocancellous bone chips into a structured strut graft for treating segmental bone defects. A total of 24 adult New Zealand white rabbits underwent a left femoral segmental bone defect creation. Twelve rabbits in group A underwent three-dimensional (3D printed cage insertion, corticocancellous chips implantation, and Kirschner-wire (K-wire fixation, while the other 12 rabbits in group B received bone chips implantation and K-wire fixation only. All rabbits received a one-week activity assessment and the initial image study at postoperative 1 week. The final image study was repeated at postoperative 12 or 24 weeks before the rabbit scarification procedure on schedule. After the animals were sacrificed, both femurs of all the rabbits were prepared for leg length ratios and 3-point bending tests. The rabbits in group A showed an increase of activities during the first week postoperatively and decreased anterior cortical disruptions in the postoperative image assessments. Additionally, higher leg length ratios and 3-point bending strengths demonstrated improved final bony ingrowths within the bone defects for rabbits in group A. In conclusion, through this bone graft converting technique, orthopedic surgeons can treat segmental bone defects by using bone chips but with imitate characters of structured cortical bone graft.

  2. Development of a Three-Dimensional (3D) Printed Biodegradable Cage to Convert Morselized Corticocancellous Bone Chips into a Structured Cortical Bone Graft.

    Science.gov (United States)

    Chou, Ying-Chao; Lee, Demei; Chang, Tzu-Min; Hsu, Yung-Heng; Yu, Yi-Hsun; Liu, Shih-Jung; Ueng, Steve Wen-Neng

    2016-04-20

    This study aimed to develop a new biodegradable polymeric cage to convert corticocancellous bone chips into a structured strut graft for treating segmental bone defects. A total of 24 adult New Zealand white rabbits underwent a left femoral segmental bone defect creation. Twelve rabbits in group A underwent three-dimensional (3D) printed cage insertion, corticocancellous chips implantation, and Kirschner-wire (K-wire) fixation, while the other 12 rabbits in group B received bone chips implantation and K-wire fixation only. All rabbits received a one-week activity assessment and the initial image study at postoperative 1 week. The final image study was repeated at postoperative 12 or 24 weeks before the rabbit scarification procedure on schedule. After the animals were sacrificed, both femurs of all the rabbits were prepared for leg length ratios and 3-point bending tests. The rabbits in group A showed an increase of activities during the first week postoperatively and decreased anterior cortical disruptions in the postoperative image assessments. Additionally, higher leg length ratios and 3-point bending strengths demonstrated improved final bony ingrowths within the bone defects for rabbits in group A. In conclusion, through this bone graft converting technique, orthopedic surgeons can treat segmental bone defects by using bone chips but with imitate characters of structured cortical bone graft.

  3. Tensile material properties of human rib cortical bone under quasi-static and dynamic failure loading and influence of the bone microstucture on failure characteristics

    CERN Document Server

    Subit, Damien; Valazquez-Ameijide, Juan; Arregui-Dalmases, Carlos; Crandall, Jeff

    2011-01-01

    Finite element models of the thorax are under development to assist vehicle safety researchers with the design of countermeasures such as advanced restrain systems. Computational models have become more refined with increasing geometrical complexity as element size decreases. These finite element models can now capture small geometrical features with an attempt to predict fracture. However, the bone material properties currently available, and in particular the rate sensitivity, have been mainly determined from compression tests or tests on long bones. There is a need for a new set of material properties for the human rib cortical bone. With this objective, a new clamping technique was developed to test small bone coupons under tensile loading. Ten coupons were harvested from the cortical shell of the sixth and seventh left ribs from three cadavers. The coupons were tested to fracture under quasi-static (target strain rate of 0.07 %/s) and dynamic loading (target strain rate of 170 %/s). Prior to testing, eac...

  4. Cortical thickness and semantic fluency in Alzheimer's disease and mild cognitive impairment

    OpenAIRE

    Eastman, Jennifer A.; Hwang, Kristy S.; Lazaris, Andreas; Chow, Nicole; Ramirez, Leslie; Babakchanian, Sona; Woo, Ellen; Thompson, Paul M; Apostolova, Liana G

    2013-01-01

    The hallmark of Alzheimer's disease (AD) is declarative memory loss, but deficits in semantic fluency are also observed. We assessed how semantic fluency relates to cortical atrophy to identify specific regions that play a role in the loss of access to semantic information. Whole-brain structural magnetic resonance imaging (MRI) data were analyzed from 9 Normal Control (NC)(M=76.7, SD=5.6), 40 Mild Cognitive Impairment (MCI) (M=74.4, SD=8.6), and 10 probable AD (M=72.4, SD=8.0) subjects from ...

  5. Alterations in cortical thickness and neuronal density in the frontal cortex of Albert Einstein.

    Science.gov (United States)

    Anderson, B; Harvey, T

    1996-06-07

    Neuronal density, neuron size, and the number of neurons under 1 mm2 of cerebral cortical surface area were measured in the right pre-frontal cortex of Albert Einstein and five elderly control subjects. Measurement of neuronal density used the optical dissector technique on celloidin-embedded cresyl violet-stained sections. The neurons counted provided a systematic random sample for the measurement of cell body cross-sectional area. Einstein's cortex did not differ from the control subjects in the number of neurons under 1 mm2 of cerebral cortex or in mean neuronal size. Because Einstein's cortex was thinner than the controls he had a greater neuronal density.

  6. A 3D Multiscale Modelling of Cortical Bone Structure, Using the Inverse Identification Method: Microfibril Scale Study

    CERN Document Server

    Barkaoui, Abdelwahed

    2011-01-01

    Complexity and heterogeneity of bone tissue require a multiscale modelling to understand their mechanical behaviour and their remodelling mechanism. Human cortical bone structure consists of six structural scale levels which are the (macroscopic) cortical bone, osteonal, lamellar, fibrous, fibril and microfibril. In this paper, a 3D model based on finite elements method was achieved to study the nanomechanical behaviour of collagen Microfibril. The mechanical properties and the geometry (gap, overlap and diameter) of both tropocollagen and mineral were taken into consideration as well as the effects of cross-links. An inverse identification method has been applied to determine equivalent averaged properties in order to link up these nanoscopic characteristics to the macroscopic mechanical behaviour of bone tissue. Results of nanostructure modelling of the nanomechanical properties of strain deformation under varying cross-links were investigated in this work.

  7. Biomedical titanium alloys with Young’s moduli close to that of cortical bone

    Science.gov (United States)

    Niinomi, Mitsuo; Liu, Yi; Nakai, Masaki; Liu, Huihong; Li, Hua

    2016-01-01

    Biomedical titanium alloys with Young’s moduli close to that of cortical bone, i.e., low Young’s modulus titanium alloys, are receiving extensive attentions because of their potential in preventing stress shielding, which usually leads to bone resorption and poor bone remodeling, when implants made of their alloys are used. They are generally β-type titanium alloys composed of non-toxic and allergy-free elements such as Ti–29Nb–13Ta–4.6Zr referred to as TNTZ, which is highly expected to be used as a biomaterial for implants replacing failed hard tissue. Furthermore, to satisfy the demands from both patients and surgeons, i.e., a low Young’s modulus of the whole implant and a high Young’s modulus of the deformed part of implant, titanium alloys with changeable Young’s modulus, which are also β-type titanium alloys, for instance Ti–12Cr, have been developed. In this review article, by focusing on TNTZ and Ti–12Cr, the biological and mechanical properties of the titanium alloys with low Young’s modulus and changeable Young’s modulus are described. In addition, the titanium alloys with shape memory and superelastic properties were briefly addressed. Surface modifications for tailoring the biological and anti-wear/corrosion performances of the alloys have also been briefly introduced. PMID:27252887

  8. Biomedical titanium alloys with Young's moduli close to that of cortical bone.

    Science.gov (United States)

    Niinomi, Mitsuo; Liu, Yi; Nakai, Masaki; Liu, Huihong; Li, Hua

    2016-09-01

    Biomedical titanium alloys with Young's moduli close to that of cortical bone, i.e., low Young's modulus titanium alloys, are receiving extensive attentions because of their potential in preventing stress shielding, which usually leads to bone resorption and poor bone remodeling, when implants made of their alloys are used. They are generally β-type titanium alloys composed of non-toxic and allergy-free elements such as Ti-29Nb-13Ta-4.6Zr referred to as TNTZ, which is highly expected to be used as a biomaterial for implants replacing failed hard tissue. Furthermore, to satisfy the demands from both patients and surgeons, i.e., a low Young's modulus of the whole implant and a high Young's modulus of the deformed part of implant, titanium alloys with changeable Young's modulus, which are also β-type titanium alloys, for instance Ti-12Cr, have been developed. In this review article, by focusing on TNTZ and Ti-12Cr, the biological and mechanical properties of the titanium alloys with low Young's modulus and changeable Young's modulus are described. In addition, the titanium alloys with shape memory and superelastic properties were briefly addressed. Surface modifications for tailoring the biological and anti-wear/corrosion performances of the alloys have also been briefly introduced.

  9. An Increase in Forearm Cortical Bone Size After Menopause May Influence the Estimated Bone Mineral Loss--A 28-Year Prospective Observational Study.

    Science.gov (United States)

    Karlsson, Magnus K; Ahlborg, Henrik G; Svejme, Ola; Nilsson, Jan-Åke; Rosengren, Björn E

    2016-01-01

    Areal bone mineral density (aBMD) is the most common estimate of bone mass, incorporated in the World Health Organization definition of osteoporosis. However, aBMD depends on not only the amount of mineral but also the bone size. The estimated postmenopausal decline in aBMD could because of this be influenced by changes in bone size.We measured bone mineral content (BMC; mg), aBMD (mg/cm2), and bone width (mm) by single-photon absorptiometry at the cortical site of the forearm in a population-based sample of 105 Caucasian women. We conducted 12 measurements during a 28-yr period from mean 5 yr (range: 2-9) before menopause to mean 24 yr (range: 18-28) after menopause. We calculated individual slopes for changes in the periods before menopause, 0-transient increase in forearm bone size that will influence the by aBMD estimated cortical loss in bone minerals. Published by Elsevier Inc.

  10. Microstructure and compressive mechanical properties of cortical bone in children with osteogenesis imperfecta treated with bisphosphonates compared with healthy children.

    Science.gov (United States)

    Imbert, Laurianne; Aurégan, Jean-Charles; Pernelle, Kélig; Hoc, Thierry

    2015-06-01

    Osteogenesis imperfecta (OI) is a genetic disorder characterized by a change in bone tissue quality, but little data are available to describe the factors involved at the macroscopic scale. To better understand the effect of microstructure alterations on the mechanical properties at the sample scale, we studied the structural and mechanical properties of six cortical bone samples from children with OI treated with bisphosphonates and compared them to the properties of three controls. Scanning electron microscopy, high resolution computed tomography and compression testing were used to assess these properties. More resorption cavities and a higher osteocyte lacunar density were observed in OI bone compared with controls. Moreover, a higher porosity was measured for OI bones along with lower macroscopic Young's modulus, yield stress and ultimate stress. The microstructure was impaired in OI bones; the higher porosity and osteocyte lacunar density negatively impacted the mechanical properties and made the bone more prone to fracture.

  11. Harvesting bone graft from the olecranon: a quantitative and biomechanical comparison of proximal and dorsal cortical windows.

    Science.gov (United States)

    Anderson, Matthew C; Chong, Alexander C M; Lucas, George L; Czuwala, Peter J; Wooley, Paul H

    2014-07-01

    We conducted a study to compare 2 techniques of harvesting ulna bone graft from the olecranon, one using a proximal cortical window (PCW), the other using a dorsal cortical window (DCW), in terms of cancellous bone graft quantity and ulna fracture strength after graft harvest. Cancellous bone was harvested from 8 pairs of embalmed cadaver proximal ulna. Each side of a matched pair was randomly assigned to graft harvest using either a PCW or a DCW approach. Packed bone volume (PBV) was determined by placing the harvested bone into a 3-mL syringe and compacting it with a quasi-static 25-N load. Biomechanical cantilever bending was performed on each elbow to determine load at failure (LF). Paired Student t tests were used to compare PBV and LF between the experimental and control groups. The graft PBV obtained from the matched-pair specimens was not statistically different between the PCW and DCW approaches. Ulnas subjected to proximal bone harvest exhibited higher LF than ulnas subjected to dorsal bone harvest, though the difference was not statistically significant. Compared with bone graft harvest using the traditional DCW approach, harvest using a PCW approach provides similar cancellous graft amounts and exhibits similar fracture resistance.

  12. Medial prefrontal and anterior cingulate cortical thickness predicts shared individual differences in self-generated thought and temporal discounting.

    Science.gov (United States)

    Bernhardt, Boris C; Smallwood, Jonathan; Tusche, Anita; Ruby, Florence J M; Engen, Haakon G; Steinbeis, Nikolaus; Singer, Tania

    2014-04-15

    When deprived of compelling perceptual input, the mind is often occupied with thoughts unrelated to the immediate environment. Previous behavioral research has shown that this self-generated task-unrelated thought (TUT), especially under non-demanding conditions, relates to cognitive capacities such as creativity, planning, and reduced temporal discounting. Despite the frequency and importance of this type of cognition, little is known about its structural brain basis. Using MRI-based cortical thickness measures in 37 participants, we were able to show that individuals with a higher tendency to engage in TUT under low-demanding conditions (but not under high-demanding conditions) show an increased thickness of medial prefrontal cortex (mPFC) and anterior/midcingulate cortex. Thickness of these regions also related to less temporal discounting (TD) of monetary rewards in an economic task, indicative of more patient decision-making. The findings of a shared structural substrate in mPFC and anterior/midcingulate cortex underlying both TUT and TD suggest an important role of these brain regions in supporting the self-generation of information that is unrelated to the immediate environment and which may be adaptive in nature. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Analysis of cortical bone porosity using synchrotron radiation microtomography to evaluate the effects of chemotherapy

    Science.gov (United States)

    Alessio, R.; Nogueira, L. P.; Salata, C.; Mantuano, A.; Almeida, A. P.; Braz, D.; de Almeida, C. E.; Tromba, G.; Barroso, R. C.

    2015-11-01

    Microporosities play important biologic and mechanical roles on health. One of the side effects caused by some chemotherapy drugs is the induction of amenorrhea, temporary or not, in premenopausal women, with a consequent decrease in estrogen production, which can lead to cortical bone changes. In the present work, the femur diaphysis of rats treated with chemotherapy drugs were evaluated by 3D morphometric parameters using synchrotron radiation microtomography. Control animals were also evaluated for comparison. The 3D tomographic images were obtained at the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline at the ELETTRA Synchrotron Laboratory in Trieste, Italy. Results showed significant differences in morphometric parameters measured from the 3D images of femur diaphysis of rats.

  14. Reference point indentation study of age-related changes in porcine femoral cortical bone.

    Science.gov (United States)

    Rasoulian, Ramin; Raeisi Najafi, Ahmad; Chittenden, Michael; Jasiuk, Iwona

    2013-06-21

    The reference point indentation (RPI) method is a microindentation technique involving successive indentation cycles. We employed RPI to measure average stiffness (Ave US), indentation distance increase (IDI), total indentation distance (TID), average energy dissipated (Ave ED), and creep indentation distance (CID) of swine femoral cortical bone (mid-diaphysis) as a function of age (1, 3.5, 6, 14.5, 24, and 48 months) and loading directions (longitudinal and transverse). The Ave US increases with animal age, while the IDI, TID, Ave ED, and CID decrease with age, for both longitudinal (transverse surface) and transverse (periosteal surface) loading directions. Longitudinal measurements generally give higher Ave US and lower IDI and TID values compared to transverse measurements. The RPI measurements show similar trends to those obtained using nanoindentation test, and ash and water content tests.

  15. The reliability of cone-beam computed tomography to analyze trabecular and cortical bone structures: an in-vitro study

    OpenAIRE

    Huang, Yan; Dessel, Jeroen Van; Nicolielo, Laura; Van de Casteele, Elke; Slagmolen, Pieter; Jacobs, Reinhilde

    2015-01-01

    Huang Y., Van Dessel J., Nicolielo L., Van de Casteele E., Slagmolen P., Jacobs R., ''The reliability of cone-beam computed tomography to analyze trabecular and cortical bone structures: an in-vitro study'', 24th annual congress of the European Association for Osseointegration - EAO 2015, September 24-26, 2015, Stockholm, Sweden.

  16. A cone-beam computed tomography evaluation of buccal bone thickness following maxillary expansion

    Energy Technology Data Exchange (ETDEWEB)

    Akyalcin, Sercan; Englih, Jeryl D.; Stephens, Claude R.; Winkelmann, Sam [Dept. of Orthodontics, School of Dentistry, University of Texas Health Science Center at Houston, Houston (United States); Schaefer, Jeffrey S. [Todd Hughes Orthodontics, Houston (United States)

    2013-06-15

    This study was performed to determine the buccal alveolar bone thickness following rapid maxillary expansion (RME) using cone-beam computed tomography (CBCT). Twenty-four individuals (15 females, 9 males; 13.9 years) that underwent RME therapy were included. Each patient had CBCT images available before (T1), after (T2), and 2 to 3 years after (T3) maxillary expansion therapy. Coronal multiplanar reconstruction images were used to measure the linear transverse dimensions, inclinations of teeth, and thickness of the buccal alveolar bone. One-way ANOVA analysis was used to compare the changes between the three times of imaging. Pairwise comparisons were made with the Bonferroni method. The level of significance was established at p<0.05. The mean changes between the points in time yielded significant differences for both molar and premolar transverse measurements between T1 and T2 (p<0.05) and between T1 and T3 (p<0.05). When evaluating the effect of maxillary expansion on the amount of buccal alveolar bone, a decrease between T1 and T2 and an increase between T2 and T3 were found in the buccal bone thickness of both the maxillary first premolars and maxillary first molars. However, these changes were not significant. Similar changes were observed for the angular measurements. RME resulted in non-significant reduction of buccal bone between T1 and T2. These changes were reversible in the long-term with no evident deleterious effects on the alveolar buccal bone.

  17. The alterations of cortical volume, thickness, surface and density in the intermediate sporadic Parkinson's disease from the Han population of Mainland China

    Directory of Open Access Journals (Sweden)

    Xia Deng

    2016-08-01

    Full Text Available Many symptoms of sporadic Parkinson's disease (sPD can’t be completely explained by the lesion of simple typical extrapyramidal circuit between striatum and substantia nigra. Therefore, we investigated the alteration of cortical volume, thickness, surface and density in the intermediate sPD from the Han population of Mainland China in order to find the new pathological brain regions associated with the complex clinical manifestations of sPD. The cortical volume, thickness, surface and density were examined using the voxel-based cortical morphometry and corticometry on magnetic resonance image (MRI in 67 intermediate sPD and 35 controls, the multiple adjusted comparisons analysis of all MRI data were employed to assess the relationships between the cortical morphometric alteration in the specific brain regions and sPD. Results showed that a significantly shrunk volume, thinned thickness and enlarged or reduced surface of cortex in some specific brain regions were closely associated with sPD, but all cortical densities were not different. The majority of morphometric alteration of hemisphere cortex was symmetric, but that in the left hemisphere was more significant. The cortical morphometric alterations in the frontal, temporal, parietal, occipital and limbic lobe, cerebellum, caudate and thalamus were closely related to the clinical neural dysfunction (Clinical manifestations of sPD. Our data indicated that the deficits of extensive brain regions involved in the development of sPD, resulted in a series of correspondent complex clinical manifestations in the disease.

  18. Scanning transmission electron microscopic tomography of cortical bone using Z-contrast imaging.

    Science.gov (United States)

    McNally, Elizabeth; Nan, Feihong; Botton, Gianluigi A; Schwarcz, Henry P

    2013-06-01

    Previously we presented (McNally et al., 2012) a model for the ultrastructure of bone showing that the mineral resides principally outside collagen fibrils in the form of 5 nm thick mineral structures hundreds of nanometers long oriented parallel to the fibrils. Here we use high-angle annular dark-field electron tomography in the scanning transmission electron microscope to confirm this model and further elucidate the composite structure. Views of a section cut parallel to the fibril axes show bundles of mineral structures extending parallel to the fibrils and encircling them. The mineral density inside the fibrils is too low to be visualized in these tomographic images. A section cut perpendicular to the fibril axes, shows quasi-circular walls composed of mineral structures, wrapping around apparently empty holes marking the sites of fibrils. These images confirm our original model that the majority of mineral in bone resides outside the collagen fibrils.

  19. Automated volumetry and regional thickness analysis of hippocampal subfields and medial temporal cortical structures in mild cognitive impairment.

    Science.gov (United States)

    Yushkevich, Paul A; Pluta, John B; Wang, Hongzhi; Xie, Long; Ding, Song-Lin; Gertje, Eske C; Mancuso, Lauren; Kliot, Daria; Das, Sandhitsu R; Wolk, David A

    2015-01-01

    We evaluate a fully automatic technique for labeling hippocampal subfields and cortical subregions in the medial temporal lobe in in vivo 3 Tesla MRI. The method performs segmentation on a T2-weighted MRI scan with 0.4 × 0.4 × 2.0 mm(3) resolution, partial brain coverage, and oblique orientation. Hippocampal subfields, entorhinal cortex, and perirhinal cortex are labeled using a pipeline that combines multi-atlas label fusion and learning-based error correction. In contrast to earlier work on automatic subfield segmentation in T2-weighted MRI [Yushkevich et al., 2010], our approach requires no manual initialization, labels hippocampal subfields over a greater anterior-posterior extent, and labels the perirhinal cortex, which is further subdivided into Brodmann areas 35 and 36. The accuracy of the automatic segmentation relative to manual segmentation is measured using cross-validation in 29 subjects from a study of amnestic mild cognitive impairment (aMCI) and is highest for the dentate gyrus (Dice coefficient is 0.823), CA1 (0.803), perirhinal cortex (0.797), and entorhinal cortex (0.786) labels. A larger cohort of 83 subjects is used to examine the effects of aMCI in the hippocampal region using both subfield volume and regional subfield thickness maps. Most significant differences between aMCI and healthy aging are observed bilaterally in the CA1 subfield and in the left Brodmann area 35. Thickness analysis results are consistent with volumetry, but provide additional regional specificity and suggest nonuniformity in the effects of aMCI on hippocampal subfields and MTL cortical subregions. © 2014 Wiley Periodicals, Inc.

  20. Multiscale approach including microfibril scale to assess elastic constants of cortical bone based on neural network computation and homogenization method

    CERN Document Server

    Barkaoui, Abdelwahed; Tarek, Merzouki; Hambli, Ridha; Ali, Mkaddem

    2014-01-01

    The complexity and heterogeneity of bone tissue require a multiscale modelling to understand its mechanical behaviour and its remodelling mechanisms. In this paper, a novel multiscale hierarchical approach including microfibril scale based on hybrid neural network computation and homogenisation equations was developed to link nanoscopic and macroscopic scales to estimate the elastic properties of human cortical bone. The multiscale model is divided into three main phases: (i) in step 0, the elastic constants of collagen-water and mineral-water composites are calculated by averaging the upper and lower Hill bounds; (ii) in step 1, the elastic properties of the collagen microfibril are computed using a trained neural network simulation. Finite element (FE) calculation is performed at nanoscopic levels to provide a database to train an in-house neural network program; (iii) in steps 2 to 10 from fibril to continuum cortical bone tissue, homogenisation equations are used to perform the computation at the higher s...

  1. Mid-thigh cortical bone structural parameters, muscle mass and strength, and association with lower limb fractures in older men and women (AGES-Reykjavik Study).

    Science.gov (United States)

    Johannesdottir, Fjola; Aspelund, Thor; Siggeirsdottir, Kristin; Jonsson, Brynjolfur Y; Mogensen, Brynjolfur; Sigurdsson, Sigurdur; Harris, Tamara B; Gudnason, Vilmundur G; Lang, Thomas F; Sigurdsson, Gunnar

    2012-05-01

    In a cross-sectional study we investigated the relationship between muscle and bone parameters in the mid-thigh in older people using data from a single axial computed tomographic section through the mid-thigh. Additionally, we studied the association of these variables with incident low-trauma lower limb fractures. A total of 3,762 older individuals (1,838 men and 1,924 women), aged 66-96 years, participants in the AGES-Reykjavik study, were studied. The total cross-sectional muscular area and knee extensor strength declined with age similarly in both sexes. Muscle parameters correlated most strongly with cortical area and total shaft area (adjusted for age, height, and weight) but explained lower limb fractures. Small muscular area, low knee extensor strength, large MA, low cortical thickness, and high BR were significantly associated with fractures in both sexes. Our results show that bone and muscle loss proceed at different rates and with different gender patterns.

  2. Vitamin D, carotid intima-media thickness and bone structure in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Winckler, Karoline; Tarnow, Lise; Lundby-Christensen, Louise

    2015-01-01

    Despite aggressive treatment of cardiovascular disease (CVD) risk factors individuals with type 2 diabetes (T2D) still have increased risk of cardiovascular morbidity and mortality. The primary aim of this study was to examine the cross-sectional association between total (25-hydroxy vitamin D (25...... of diabetes 12±6 years), including 294 patients (71%) treated with insulin. Carotid intima-media thickness (IMT) and arterial stiffness (carotid artery distensibility coefficient (DC) and Young's elastic modulus (YEM)) were measured by ultrasound scan as indicators of CVD. Bone health was assessed by bone...... mineral density and trabecular bone score measured by dual energy X-ray absorptiometry. In this cohort, 214 patients (52%) were vitamin D deficient (25(OH)D

  3. Functional adaptation to mechanical loading in both cortical and cancellous bone is controlled locally and is confined to the loaded bones.

    Science.gov (United States)

    Sugiyama, Toshihiro; Price, Joanna S; Lanyon, Lance E

    2010-02-01

    In order to validate whether bones' functional adaptation to mechanical loading is a local phenomenon, we randomly assigned 21 female C57BL/6 mice at 19 weeks of age to one of three equal numbered groups. All groups were treated with isoflurane anesthesia three times a week for 2 weeks (approximately 7 min/day). During each anaesthetic period, the right tibiae/fibulae in the DYNAMIC+STATIC group were subjected to a peak dynamic load of 11.5 N (40 cycles with 10-s intervals between cycles) superimposed upon a static "pre-load" of 2.0 N. This total load of 13.5 N engendered peak longitudinal strains of approximately 1400 microstrain on the medial surface of the tibia at a middle/proximal site. The right tibiae/fibulae in the STATIC group received the static "pre-load" alone while the NOLOAD group received no artificial loading. After 2 weeks, the animals were sacrificed and both tibiae, fibulae, femora, ulnae and radii analyzed by three-dimensional high-resolution (5 mum) micro-computed tomography (microCT). In the DYNAMIC+STATIC group, the proximal trabecular percent bone volume and cortical bone volume at the proximal and middle levels of the right tibiae as well as the cortical bone volume at the middle level of the right fibulae were markedly greater than the left. In contrast, the left bones in the DYNAMIC+STATIC group showed no differences compared to the left or right bones in the NOLOAD or STATIC group. These microCT data were confirmed by two-dimensional examination of fluorochrome labels in bone sections which showed the predominantly woven nature of the new bone formed in the loaded bones. We conclude that the adaptive response in both cortical and trabecular regions of bones subjected to short periods of dynamic loading, even when this response is sufficiently vigorous to stimulate woven bone formation, is confined to the loaded bones and does not involve changes in other bones that are adjacent, contra-lateral or remote to them.

  4. Genetic algorithms as a useful tool for trabecular and cortical bone segmentation.

    Science.gov (United States)

    Janc, K; Tarasiuk, J; Bonnet, A S; Lipinski, P

    2013-07-01

    The aim of this study was to find a semi-automatic method of bone segmentation on the basis of computed tomography (CT) scan series in order to recreate corresponding 3D objects. So, it was crucial for the segmentation to be smooth between adjacent scans. The concept of graphics pipeline computing was used, i.e. simple graphics filters such as threshold or gradient were processed in a manner that the output of one filter became the input of the second one resulting in so called pipeline. The input of the entire stream was the CT scan and the output corresponded to the binary mask showing where a given tissue is located in the input image. In this approach the main task consists in finding the suitable sequence, types and parameters of graphics filters building the pipeline. Because of the high number of desired parameters (in our case 96), it was decided to use a slightly modified genetic algorithm. To determine fitness value, the mask obtained from the parameters found through genetic algorithms (GA) was compared with those manually prepared. The numerical value corresponding to such a comparison has been defined by Dice's coefficient. Preparation of reference masks for a few scans among the several hundreds of them was the only action done manually by a human expert. Using this method, very good results both for trabecular and cortical bones were obtained. It has to be emphasized that as no real border exists between these two bone types, the manually prepared reference masks were quite conventional and therefore charged with errors. As GA is a non-deterministic method, the present work also contains a statistical analysis of the relations existing between various GA parameters and fitness function. Finally the best sets of the GA parameters are proposed.

  5. Liver-derived IGF-I regulates cortical bone mass but is dispensable for the osteogenic response to mechanical loading in female mice.

    Science.gov (United States)

    Svensson, Johan; Windahl, Sara H; Saxon, Leanne; Sjögren, Klara; Koskela, Antti; Tuukkanen, Juha; Ohlsson, Claes

    2016-07-01

    Low circulating IGF-I is associated with increased fracture risk. Conditional depletion of IGF-I produced in osteoblasts or osteocytes inhibits the bone anabolic effect of mechanical loading. Here, we determined the role of endocrine IGF-I for the osteogenic response to mechanical loading in young adult and old female mice with adult, liver-specific IGF-I inactivation (LI-IGF-I(-/-) mice, serum IGF-I reduced by ≈70%) and control mice. The right tibia was subjected to short periods of axial cyclic compressive loading three times/wk for 2 wk, and measurements were performed using microcomputed tomography and mechanical testing by three-point bending. In the nonloaded left tibia, the LI-IGF-I(-/-) mice had lower cortical bone area and increased cortical porosity, resulting in reduced bone mechanical strength compared with the controls. Mechanical loading induced a similar response in LI-IGF-I(-/-) and control mice in terms of cortical bone area and trabecular bone volume fraction. In fact, mechanical loading produced a more marked increase in cortical bone mechanical strength, which was associated with a less marked increase in cortical porosity, in the LI-IGF-I(-/-) mice compared with the control mice. In conclusion, liver-derived IGF-I regulates cortical bone mass, cortical porosity, and mechanical strength under normal (nonloaded) conditions. However, despite an ∼70% reduction in circulating IGF-I, the osteogenic response to mechanical loading was not attenuated in the LI-IGF-I(-/-) mice.

  6. Nasal bone length, prenasal thickness, prenasal thickness-to-nasal bone length ratio and prefrontal space ratio in second- and third-trimester fetuses with Down syndrome.

    Science.gov (United States)

    Vos, F I; De Jong-Pleij, E A P; Bakker, M; Tromp, E; Pajkrt, E; Kagan, K O; Bilardo, C M

    2015-02-01

    To evaluate nasal bone length (NBL), prenasal thickness (PT), prenasal thickness-to-nasal bone length (PT-NBL) ratio and prefrontal space ratio (PFSR) as markers for Down syndrome in the second and third trimesters. NBL, PT, PT-NBL ratio and PFSR were measured retrospectively in stored two-dimensional images or three-dimensional volumes (corrected to the mid-sagittal plane) of fetuses with Down syndrome, which were retrieved from the digital databases of participating units. Measurements were performed on the stored images and volumes by two experienced operators, and the values obtained were compared to our previously reported normal ranges for euploid fetuses in order to assess the detection rates for Down syndrome. A total of 159 fetuses with Down syndrome were included in the analysis, six of which were excluded because of inadequate available images. Median maternal age was 36.0 years and median gestational age was 23 + 1 weeks. NBL and PT were correlated with gestational age (P Down syndrome, the PT-NBL ratio yielded the highest detection rate (86.2%), followed by PFSR (79.7%), PT (63.4%) and NBL (61.9%). All markers were abnormal in 33.6% of cases, whilst all were normal in 4.7%. At least one of the four markers was abnormal in 95.3%, and either the PT-NBL ratio or PFSR was abnormal in 93.8%. Detection rates were not related to gestational age. The PT-NBL ratio and PFSR are robust second- and third-trimester markers for Down syndrome. Both provide high detection rates and are easy to use, as the cut-off for normality is constant throughout gestation. Ltd. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

  7. Task complexity and location specific changes of cortical thickness in executive and salience networks after working memory training

    Science.gov (United States)

    Metzler-Baddeley, Claudia; Caeyenberghs, Karen; Foley, Sonya; Jones, Derek K.

    2016-01-01

    Novel activities and experiences shape the brain's structure and organisation and, hence, our behaviour. However, evidence from structural plasticity studies remains mixed and the neural correlates of learning and practice are still poorly understood. We conducted a robustly designed study into grey matter plasticity following 2 months of working memory training. We generated a priori hypotheses regarding the location of plastic effects across three cognitive control networks (executive, anterior salience and basal ganglia networks), and compared the effects of adaptive training (n = 20) with a well-matched active control group (n = 20) which differed in training complexity and included extensive cognitive assessment before and after the training. Adaptive training relative to control activities resulted in a complex pattern of subtle and localised structural changes: Training was associated with increases in cortical thickness in right-lateralised executive regions, notably the right caudal middle frontal cortex, as well as increases in the volume of the left pallidum. In addition the training group showed reductions of thickness in the right insula, which were correlated with training-induced improvements in backward digit span performance. Unexpectedly, control activities were associated with reductions in thickness in the right pars triangularis. These results suggest that the direction of activity-induced plastic changes depend on the level of training complexity as well as brain location. These observations are consistent with the view that the brain responds dynamically to environmental demands by focusing resources on task relevant networks and eliminating irrelevant processing for the purpose of energy reduction. PMID:26806288

  8. Mechanical and material properties of cortical and trabecular bone from cannabinoid receptor-1-null (Cnr1(-/-)) mice.

    Science.gov (United States)

    Khalid, Aysha B; Goodyear, Simon R; Ross, Ruth A; Aspden, Richard M

    2016-10-01

    The endocannabinoid system is known for its regulatory effects on bone metabolism through the cannabinoid receptors, Cnr1 and Cnr2. In this study we analysed the mechanical and material properties of long bones from Cnr1(-/-) mice on a C57BL/6 background. Tibiae and femora from 5- and 12-week-old mice were subjected to three-point bending to measure bending stiffness and yield strength. Elastic modulus, density and mineral content were measured in the diaphysis. Second moment of area (MOA2), inner and outer perimeters of the cortical shaft and trabecular fractional bone volume (BV/TV) were measured using micro-CT. In Cnr1(-/-) males and females at both ages the bending stiffness was reduced due to a smaller MOA2. Bone from Cnr1(-/-) females had a greater modulus than wild-type controls, although no differences were observed in males. BV/TV of 12-week-old Cnr1(-/-) females was greater than controls, although no difference was seen at 5-weeks. On the contrary, Cnr1(-/-) males had the same BV/TV as controls at 12-weeks while they had significantly lower values at 5-weeks. This study shows that deleting Cnr1 decreases the amount of cortical bone in both males and females at 12-weeks, but increases the amount of trabecular bone only in females.

  9. Synchronous changes of cortical thickness and corresponding white matter microstructure during brain development accessed by diffusion MRI tractography from parcellated cortex

    Directory of Open Access Journals (Sweden)

    Tina eJeon

    2015-12-01

    Full Text Available Cortical thickness (CT changes during normal brain development is associated with complicated cellular and molecular processes including synaptic pruning and apoptosis. In parallel, the microstructural enhancement of developmental white matter (WM axons with their neuronal bodies in the cerebral cortex has been widely reported with measurements of metrics derived from diffusion tensor imaging (DTI, especially fractional anisotropy (FA. We hypothesized that the changes of CT and microstructural enhancement of corresponding axons are highly interacted during development. DTI and T1-weighted images of 50 healthy children and adolescents between the ages of 7 to 25 years were acquired. With the parcellated cortical gyri transformed from T1-weighted images to DTI space as the tractography seeds, probabilistic tracking was performed to delineate the WM fibers traced from specific parcellated cortical regions. CT was measured at certain cortical regions and FA was measured from the WM fibers traced from same cortical regions. The CT of all frontal cortical gyri, includeing Brodmann areas 4, 6, 8, 9, 10, 11, 44, 45, 46 and 47, decreased significantly and heterogeneously; concurrently, significant and heterogeneous increases of FA of WM traced from corresponding regions were found. We further revealed significant correlation between the slopes of the CT decrease and the slopes of corresponding WM FA increase in all frontal cortical gyri, suggesting coherent cortical pruning and corresponding WM microstructural enhancement. Such correlation was not found in cortical regions other than frontal cortex. The molecular and cellular mechanisms of these synchronous changes may be associated with overlapping signaling pathways of axonal guidance, synaptic pruning, neuronal apoptosis and more prevalent interstitial neurons in the prefrontal cortex. Revealing the coherence of cortical and WM structural changes during development may open a new window for

  10. Repair of sheep long bone cortical defects filled with COLLOSS, COLLOSS E, OSSAPLAST, and fresh iliac crest autograft.

    Science.gov (United States)

    Huffer, William E; Benedict, James J; Turner, A S; Briest, Arne; Rettenmaier, Robert; Springer, Marco; Walboomers, X F

    2007-08-01

    COLLOSS and COLLOSS E are osteoinductive bone void fillers consisting of bone collagen and noncollagenous proteins from bovine and equine bone, respectively. The aim of this study was to compare COLLOSS, COLLOSS E, iliac bone autograft, sintered beta tricalcium phosphate (beta-TCP; OSSAPLAST), and COLLOSS E plus OSSAPLAST. Materials were placed for 4, 8, or 24 weeks in 5-mm cortical bone defects in sheep long bones. Histological sections in a plane perpendicular to the long axis of the bone were used to measure the total repair area (original defect plus callus) and the area of bone within the total repair area. The incidence of defect union was also evaluated. At 4 and 8 weeks, defects treated with COLLOSS and COLLOSS E with or without OSSAPLAST had total repair and bone areas equivalent to autograft, and larger than OSSAPLAST-treated defects. At 8 weeks, the incidence of defect union was higher in defects treated with autograft or COLLOSS E plus OSSAPLAST than in untreated defects. At 24 weeks, the incidence of union was 100% in all treatment groups and 0% in untreated defects. The incidence of union was related to the degree of remodeling between 8 and 24 weeks. This was greater in all treated than nontreated defects. In conclusion, COLLOSS and COLLOSS E were equivalent to each other and to autograft, and superior to beta-TCP, in this study model.

  11. Structural asymmetry of the human cerebral cortex: Regional and between-subject variability of surface area, cortical thickness, and local gyrification.

    Science.gov (United States)

    Chiarello, Christine; Vazquez, David; Felton, Adam; McDowell, Alessandra

    2016-12-01

    Structural asymmetry varies across individuals, brain regions, and metrics of cortical organization. The current study investigated regional differences in asymmetry of cortical surface area, thickness, and local gyrification, and the extent of between-subject variability in these metrics, in a sample of healthy young adults (N=200). Between-subject variability in cortical structure may provide a means to assess the extent of biological flexibility or constraint of brain regions, and we explored the potential influence of this variability on the phenotypic expression of structural asymmetry. The findings demonstrate that structural asymmetries are nearly ubiquitous across the cortex, with differing regional organization for the three cortical metrics. This implies that there are multiple, only partially overlapping, maps of structural asymmetry. The results further indicate that the degree of asymmetry of a brain region can be predicted by the extent of the region's between-subject variability. These findings provide evidence that reduced biological constraint promotes the expression of strong structural asymmetry.

  12. Benefits of mineralized bone cortical allograft for immediate implant placement in extraction sites: an in vivo study in dogs

    Science.gov (United States)

    2016-01-01

    Purpose The aim of the present study was to evaluate the effectiveness of using a mineralized bone cortical allograft (MBCA), with or without a resorbable collagenous membrane derived from bovine pericardium, on alveolar bone remodeling after immediate implant placement in a dog model. Methods Six mongrel dogs were included. The test and control sites were randomly selected. Four biradicular premolars were extracted from the mandible. In control sites, implants without an allograft or membrane were placed immediately in the fresh extraction sockets. In the test sites, an MBCA was placed to fill the gap between the bone socket wall and implant, with or without a resorbable collagenous membrane. Specimens were collected after 1 and 3 months. The amount of residual particles and new bone quality were evaluated by histomorphometry. Results Few residual graft particles were observed to be closely embedded in the new bone without any contact with the implant surface. The allograft combined with a resorbable collagen membrane limited the resorption of the buccal wall in height and width. The histological quality of the new bone was equivalent to that of the original bone. The MBCA improved the quality of new bone formation, with few residual particles observed at 3 months. Conclusions The preliminary results of this animal study indicate a real benefit in obtaining new bone as well as in enhancing osseointegration due to the high resorbability of cortical allograft particles, in comparison to the results of xenografts or other biomaterials (mineralized or demineralized cancellous allografts) that have been presented in the literature. Furthermore, the use of an MBCA combined with a collagen membrane in extraction and immediate implant placement limited the extent of post-extraction resorption. PMID:27800212

  13. Development of a strain rate dependent material model of human cortical bone for computer-aided reconstruction of injury mechanisms.

    Science.gov (United States)

    Asgharpour, Zahra; Zioupos, Peter; Graw, Matthias; Peldschus, Steffen

    2014-03-01

    Computer-aided methods such as finite-element simulation offer a great potential in the forensic reconstruction of injury mechanisms. Numerous studies have been performed on understanding and analysing the mechanical properties of bone and the mechanism of its fracture. Determination of the mechanical properties of bones is made on the same basis used for other structural materials. The mechanical behaviour of bones is affected by the mechanical properties of the bone material, the geometry, the loading direction and mode and of course the loading rate. Strain rate dependency of mechanical properties of cortical bone has been well demonstrated in literature studies, but as many of these were performed on animal bones and at non-physiological strain rates it is questionable how these will apply in the human situations. High strain-rates dominate in a lot of forensic applications in automotive crashes and assault scenarios. There is an overwhelming need to a model which can describe the complex behaviour of bone at lower strain rates as well as higher ones. Some attempts have been made to model the viscoelastic and viscoplastic properties of the bone at high strain rates using constitutive mathematical models with little demonstrated success. The main objective of the present study is to model the rate dependent behaviour of the bones based on experimental data. An isotropic material model of human cortical bone with strain rate dependency effects is implemented using the LS-DYNA material library. We employed a human finite element model called THUMS (Total Human Model for Safety), developed by Toyota R&D Labs and the Wayne State University, USA. The finite element model of the human femur is extracted from the THUMS model. Different methods have been employed to develop a strain rate dependent material model for the femur bone. Results of one the recent experimental studies on human femur have been employed to obtain the numerical model for cortical femur. A

  14. Trabecular and Cortical Bone of Growing C3H Mice Is Highly Responsive to the Removal of Weightbearing.

    Directory of Open Access Journals (Sweden)

    Bing Li

    Full Text Available Genetic make-up strongly influences the skeleton's susceptibility to the loss of weight bearing with some inbred mouse strains experiencing great amounts of bone loss while others lose bone at much smaller rates. At young adulthood, female inbred C3H/HeJ (C3H mice are largely resistant to catabolic pressure induced by unloading. Here, we tested whether the depressed responsivity to unloading is inherent to the C3H genetic make-up or whether a younger age facilitates a robust skeletal response to unloading. Nine-week-old, skeletally immature, female C3H mice were subjected to 3wk of hindlimb unloading (HLU, n = 12 or served as normal baseline controls (BC, n = 10 or age-matched controls (AC, n = 12. In all mice, cortical and trabecular architecture of the femur, as well as levels of bone formation and resorption, were assessed with μCT, histomorphometry, and histology. Changes in bone marrow progenitor cell populations were determined with flow cytometry. Following 21d of unloading, HLU mice had 52% less trabecular bone in the distal femur than normal age-matched controls. Reflecting a loss of trabecular tissue compared to baseline controls, trabecular bone formation rates (BFR/BS in HLU mice were 40% lower than in age-matched controls. Surfaces undergoing osteoclastic resorption were not significantly different between groups. In the mid-diaphysis, HLU inhibited cortical bone growth leading to 14% less bone area compared to age-matched controls. Compared to AC, BFR/BS of HLU mice were 53% lower at the endo-cortical surface and 49% lower at the periosteal surface of the mid-diaphysis. The enriched osteoprogenitor cell population (OPC comprised 2% of the bone marrow stem cells in HLU mice, significantly different from 3% OPC in the AC group. These data show that bone tissue in actively growing C3H mice is lost rapidly, or fails to grow, during the removal of functional weight bearing-in contrast to the insignificant response previously

  15. Nano-structural, compositional and micro-architectural signs of cortical bone fragility at the superolateral femoral neck in elderly hip fracture patients vs. healthy aged controls.

    Science.gov (United States)

    Milovanovic, Petar; Rakocevic, Zlatko; Djonic, Danijela; Zivkovic, Vladimir; Hahn, Michael; Nikolic, Slobodan; Amling, Michael; Busse, Bjoern; Djuric, Marija

    2014-07-01

    To unravel the origins of decreased bone strength in the superolateral femoral neck, we assessed bone structural features across multiple length scales at this cortical fracture initiating region in postmenopausal women with hip fracture and in aged-matched controls. Our combined methodological approach encompassed atomic force microscopy (AFM) characterization of cortical bone nano-structure, assessment of mineral content/distribution via quantitative backscattered electron imaging (qBEI), measurement of bone material properties by reference point indentation, as well as evaluation of cortical micro-architecture and osteocyte lacunar density. Our findings revealed a wide range of differences between the fracture group and the controls, suggesting a number of detrimental changes at various levels of cortical bone hierarchical organization that may render bone fragile. Namely, mineral crystals at external cortical bone surfaces of the fracture group were larger (65.22nm±41.21nm vs. 36.75nm±18.49nm, pfracture group. Fracture cases showed nearly 35% higher cortical porosity and showed significantly reduced osteocyte lacunar density compared to controls (226±27 vs. 247±32#/mm(2), p=0.05). Along with increased crystal size, a shift towards higher mineralization and a tendency to increased cortical porosity and reduced osteocyte lacunar number delineate that cortical bone of the superolateral femoral neck bears distinct signs of fragility at various levels of its structural organization. These results contribute to the understanding of hierarchical bone structure changes in age-related fragility. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Cortical bone resorption rate in elderly persons: Estimates from long-term in vivo measurements of 90Sr in the skeleton

    Energy Technology Data Exchange (ETDEWEB)

    Shagina, N. B.; Tolstykh, E. I.; Degteva, M. O.; Anspaugh, L. R.; Napier, Bruce A.

    2012-06-01

    The rate of cortical bone resorption was assessed from long-term in vivo measurements of 90Sr content in the skeleton for men aged 50-80 years and for women 0-30 years after menopause. Measurements of 90Sr were conducted with a whole body counter for residents of the Techa Riverside communities (Southern Urals, Russia), who ingested large amounts of 90Sr as a result of releases of liquid radioactive wastes into the river from the Mayak plutonium facility in early 1950s. The results of this study showed an increase in the rate of cortical bone resorption in both men and women, as based on the use of accidentally ingested 90Sr as a tracer for bone metabolism. In men there was a continuous gradual increase in the rate of cortical bone resorption after 55 years from 2.8 to 4.5%/year by the age of 75 years. In women, there was a doubled increase in the rate of cortical bone resorption after menopause of up to 6%/year; then the rate remained unchanged for 10-12 years with a subsequent gradual decline down to 5-5.5%/year. Comparison of the rate of cortical bone resorption in men and women older than 55 years showed that women expressed significantly higher levels of cortical bone resorption.

  17. Experimental investigations and finite element simulation of cutting heat in vibrational and conventional drilling of cortical bone.

    Science.gov (United States)

    Wang, Yu; Cao, Meng; Zhao, Xiangrui; Zhu, Gang; McClean, Colin; Zhao, Yuanyuan; Fan, Yubo

    2014-11-01

    Heat generated during bone drilling could cause irreversible thermal damage, which can lead to bone necrosis or even osteomyelitis. In this study, vibrational drilling was applied to fresh bovine bones to investigate the cutting heat in comparison with conventional drilling through experimental investigation and finite element analysis (FEA). The influence of vibrational frequency and amplitude on cutting heat generation and conduction were studied. The experimental results showed that, compared with the conventional drilling, vibrational drilling could significantly reduce the cutting temperature in drilling of cortical bone (P<0.05): the cutting temperature tended to decrease with increasing vibrational frequency and amplitude. The FEA results also showed that the vibrational amplitude holds a significant effect on the cutting heat conduction.

  18. Combined treatment with GH and IGF-I: additive effect on cortical bone mass but not on linear bone growth in female rats.

    Science.gov (United States)

    Sundström, Katja; Cedervall, Therese; Ohlsson, Claes; Camacho-Hübner, Cecilia; Sävendahl, Lars

    2014-12-01

    The growth-promoting effect of combined therapy with GH and IGF-I in normal rats is not known. We therefore investigated the efficacy of treatment with recombinant human (rh)GH and/or rhIGF-I on longitudinal bone growth and bone mass in intact, prepubertal, female Sprague-Dawley rats. rhGH was injected twice daily sc (5 mg/kg·d) and rhIGF-I continuously infused sc (2.2 or 4.4 mg/kg·d) for 28 days. Longitudinal bone growth was monitored by weekly x-rays of tibiae and nose-anus length measurements, and tibial growth plate histomorphology was analyzed. Bone mass was evaluated by peripheral quantitative computed tomography. In addition, serum levels of IGF-I, rat GH, acid labile subunit, IGF binding protein-3, 150-kDa ternary complex formation, and markers of bone formation and degradation were measured. Monotherapy with rhGH was more effective than rhIGF-I (4.4 mg/kg·d) to increase tibia and nose-anus length, whereas combined therapy did not further increase tibia, or nose-anus, lengths or growth plate height. In contrast, combined rhGH and rhIGF-I (4.4 mg/kg·d) therapy had an additive stimulatory effect on cortical bone mass vs rhGH alone. Combined treatment with rhGH and rhIGF-I resulted in markedly higher serum IGF-I concentrations vs rhGH alone but did not compromise the endogenous secretion of GH. We conclude that rhIGF-I treatment augments cortical bone mass but does not further improve bone growth in rhGH-treated young, intact, female rats.

  19. The significance of crack-resistance curves to the mixed-mode fracture toughness of human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Elizabeth A.; Launey, Maximilien E.; Ritchie, Robert O.

    2010-03-25

    The majority of fracture mechanics studies on the toughness of bone have been performed under tensile loading. However, it has recently been shown that the toughness of human cortical bone in the transverse (breaking) orientation is actually much lower in shear (mode II) than in tension (mode I); a fact that is physiologically relevant as in vivo bone is invariably loaded multiaxially. Since bone is a material that derives its fracture resistance primarily during crack growth through extrinsic toughening mechanisms, such as crack deflection and bridging, evaluation of its toughness is best achieved through measurements of the crack-resistance or R-curve, which describes the fracture toughness as a function of crack extension. Accordingly, in this study, we attempt to measure for the first time the R-curve fracture toughness of human cortical bone under physiologically relevant mixed-mode loading conditions. We show that the resulting mixed-mode (mode I + II) toughness depends strongly on the crack trajectory and is the result of the competition between the paths of maximum mechanical driving force and 'weakest' microstructural resistance.

  20. Variation of the mineral density in cortical bone may serve to keep strain amplitudes within a physiological range.

    Science.gov (United States)

    de Jong, W C; van Ruijven, L J; Brugman, P; Langenbach, G E J

    2013-08-01

    Within-bone variation in mineral density could be functional. A heterogeneous mineral-density distribution might serve to maintain habitual amplitudes of bone strain within a non-harmful, i.e., physiological range. Regions of a bone that would be strained the most on the basis of architecture alone might have a higher mineral density to make them more stiff and resistant to strain. We hypothesised that the cortical bone of the rabbit mandible contains such a functional distribution of mineral density. We thereby expected similar mineral-density patterns in the mandibles of different individuals due to the shared masticatory function. Secondly, we hypothesised that the highest mineral densities occur in mandibular regions predicted to be exposed to the largest amplitudes of strain-when taking into account bone architecture only. Mineral-density maps of the cortical bone of rabbit mandibles were obtained using micro-computed tomography (μCT). The μCT scans of two rabbits were converted into finite-element models (FEMs). To predict mandibular deformation during biting, these models were loaded by muscle forces and reaction forces. The forces acted on the condyles and on either the incisal or molar bite point. The FEMs were assigned a homogeneous material stiffness to calculate the strain amplitudes that would occur when only the architecture of the mandibular bone would be of influence. We found the cortical bone-mineral density patterns to be similar in all six mandibles. The mineral density of the corpus was higher than that of the ramus. A second consistent feature of the mandibular mineral-density distribution was that the medial ridge of the temporal-muscle insertion groove contained more mineral than its surrounding regions. The strain amplitudes calculated with the FEMs were variable and did not feature clear corpo-ramal differences. However, specific mandibular bone sites calculated to be exposed to the largest amplitudes of strain, including the medial

  1. The impact of thickness of resorbable membrane of human origin on the ossification of bone defects: A pathohistologic study

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    Bubalo Marija

    2012-01-01

    Full Text Available Background/Aim. A wide range of resorbable and nonresorbable membranes have been investigated over the last two decades. The barrier membrane protects the defect from ingrowth of soft tissue cells and allows bone progenitor cells to develop bone within a blood clot that is formed beneath the barrier membrane. The membranes are applied to reconstruct small bony defect prior to implantation, to cover dehiscences and fenestrations around dental implants. The aim of this study was to evaluate the influence of human resorbable demineralized membrane (RHDM thickness on bone regeneration. Methods. The experiment, approved by Ethical Committee, was performed on 6 dogs and conducted into three phases. Bone defects were created in all the 6 dogs on the left side of the mandible, 8 weeks after extraction of second, third and fourth premolars. One defect was covered with RHDM 100 μ thick, one with RHDM 200 μ thick, and the third defect left empty (control defect. The histopathological analysis was done 2, 4 and 6 months after the surgery. In the third phase samples of bone tissue were taken and subjected to histopathological analysis. Results. In all the 6 dogs the defects treated with RHDM 200 μ thick showed higher level of bone regeneration in comparison with the defect treated with RHDM 100 μ thick and especially with empty defect. Conclusion. Our results demonstrated that the thicker membrane showed the least soft tissue ingrowths and promoted better bone formation at 6 months compared with a thinner one.

  2. PTH (1–34), but not strontium ranelate counteract loss of trabecular thickness and bone strength in disuse osteopenic rats

    DEFF Research Database (Denmark)

    Brüel, Annemarie; Vegger, Jens Bay; Raffalt, Anders Christer;

    2013-01-01

    +PTH+SrR (n=12 in each group). PTH was given as injections (SC) at a dosage of 60 μg/kg/d, and SrR as 900 mg/kg/d in the diet. The experiment lasted for 4weeks.BTX resulted in lower trabecular bone formation rate (−68%) and periosteal bone formation rate (−91%), and a higher fraction of osteoclast......) and periosteal (5-fold increase vs. BTX) bone formation rate, trabecular thickness (+25% vs. BTX) and femoral neck strength (+24% vs. BTX). In contrast, SrR did not influence BTX-induced loss of bone formation rate, trabecular bone volume fraction, trabecular thickness, or bone strength. Finally, no additive...

  3. Differential diagnosis of mild cognitive impairment and Alzheimer's disease using structural MRI cortical thickness, hippocampal shape, hippocampal texture, and volumetry

    Directory of Open Access Journals (Sweden)

    Lauge Sørensen

    2017-01-01

    Full Text Available This paper presents a brain T1-weighted structural magnetic resonance imaging (MRI biomarker that combines several individual MRI biomarkers (cortical thickness measurements, volumetric measurements, hippocampal shape, and hippocampal texture. The method was developed, trained, and evaluated using two publicly available reference datasets: a standardized dataset from the Alzheimer's Disease Neuroimaging Initiative (ADNI and the imaging arm of the Australian Imaging Biomarkers and Lifestyle flagship study of ageing (AIBL. In addition, the method was evaluated by participation in the Computer-Aided Diagnosis of Dementia (CADDementia challenge. Cross-validation using ADNI and AIBL data resulted in a multi-class classification accuracy of 62.7% for the discrimination of healthy normal controls (NC, subjects with mild cognitive impairment (MCI, and patients with Alzheimer's disease (AD. This performance generalized to the CADDementia challenge where the method, trained using the ADNI and AIBL data, achieved a classification accuracy 63.0%. The obtained classification accuracy resulted in a first place in the challenge, and the method was significantly better (McNemar's test than the bottom 24 methods out of the total of 29 methods contributed by 15 different teams in the challenge. The method was further investigated with learning curve and feature selection experiments using ADNI and AIBL data. The learning curve experiments suggested that neither more training data nor a more complex classifier would have improved the obtained results. The feature selection experiment showed that both common and uncommon individual MRI biomarkers contributed to the performance; hippocampal volume, ventricular volume, hippocampal texture, and parietal lobe thickness were the most important. This study highlights the need for both subtle, localized measurements and global measurements in order to discriminate NC, MCI, and AD simultaneously based on a single

  4. Comparison of lyophilization, and freezing in honey as techniques to preserve cortical bone allografts used to repair experimental femoral defects in domestic adult cats

    Directory of Open Access Journals (Sweden)

    M.P. Ferreira

    2012-04-01

    Full Text Available Cats with orthopedic conditions are a prominent part of the clinical work of veterinary. Conditions such as comminuted fractures, bone tumors and non-unions are often difficult to repair and may require the use of bone grafts for treatment. This study evaluated cortical bone allografts preserved in honey, frozen or lyophilized for correcting long bone defects created in the diaphysis of the right femur of domestic cats (n=24. In the control group (n=6, the defect was repaired using autogenous cortical bone graft. In the remaining animals (n=6/group, the defect was repaired with cortical bone allografts preserved in honey, frozen or lyophilized. Success of graft incorporation and length of time for consolidation were assessed through clinical, radiographic and histological evaluations performed up to 180 days. In the control, frozen, honey and lyophylized groups, respectively, success of graft incorporation was 91.6%, 83.3%, 75%, and 25%, with corresponding mean length of time for consolidation of 83.1, 78, 105 and 120 days. Incorporation percentage in the lyophilized group was significantly lower than in the frozen and control groups. In conclusion, bone grafts preserved in honey or frozen were effective for repairing cortical defects in the femurs of cats as compared to autogenous cortical bone grafts.

  5. Preliminary determination of calcium, phosphorus, and the calcium/phosphorus ratio in cortical bone of Chinstrap penguin using synchrotron X-ray fluorescence analysis

    Institute of Scientific and Technical Information of China (English)

    Xie Zhouqing; Cheng Bangbo; Sun Liguang; Huang Yuying; He Wei; Zhao Sanping

    2006-01-01

    Synchrotron radiation X-ray fluorescence (SR-XRF) approach was applied to analyzing of Chinstrap penguin (Pygoscelis Antarctica) cortical bone. The method enabled the in situ determination of Ca and P concentrations and the Ca/P ratio in cortical bone. The preliminary results show that: (1) there is the bone site-related difference for Ca and P concentrations. The mean values for the investigated parameters ( on a dry-weight basis) are: 30.7% (Ca) and 14.9% (P) for the femoral cortical bone, 21.4% (Ca) and 11.5% (P) for wing cortical bone. (2) The variation for the Ca/P ratio in cortical bone is lower than those for Ca and P separately.This is in agreement with the previous report that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and is more reliable for the diagnosis of bone disorders. The authors suggest that further studies be conducted to establish normal values of Ca, P and Ca/P ratio for polar animals and provide a basis for the diagnosis of bone disorders.

  6. Long-term results of the use of autogenous cortical bone columellas to replace the stapes at stapedectomy.

    Science.gov (United States)

    Bauer, Miklós; Pytel, József; Vóna, Ida; Gerlinger, Imre

    2011-05-01

    The first author has been using an autogenous cortical bone columella to replace the stapes removed during stapedectomy since 1965. The audiograms of 21 of the 271 patients operated on with this method between 1965 and 1989 (i.e. 7.7% of the possible candidates) were available 20-35 (average 26.8) years postoperatively. The operation could be regarded as successful in 20 and unsuccessful in 1 patient in the long run. The audiological data are presented individually as averages of the values obtained at 0.5, 1, 2 and 3 kHz. The averaged data (n = 21): preoperative air conduction, 58.27; bone conduction, 24.46; and air-bone gap, 33.81 dB. Postoperative best air conduction, 19.07; bone conduction, 14.10; and air-bone gap, 4.97 dB. Postoperative recent air conduction, 45.77; bone conduction, 38.45; and air-bone gap, 7.32 dB. The best values were measured 1-8 (average 1.57) years postoperatively. In relation to the postoperative best value, the recent value of the air-bone gap had deteriorated by 2.35 dB, and that of the bone conduction by 24.35 dB. The small air-bone gap indicates that the deterioration of the hearing is mainly caused by the deterioration of the function of the inner ear and not by that of the conductive apparatus. The progression of the deterioration differs individually (0.3-1.6, average 0.93 dB/year) and accelerates with age. This finding seems to be a problem that does not depend on the operative technique. The data show that the autogenous bone columella ensures the same good and lasting results as the alloplastic solutions; moreover, there is no problem with the incus-prosthesis connection.

  7. A living thick nanofibrous implant bifunctionalized with active growth factor and stem cells for bone regeneration

    Directory of Open Access Journals (Sweden)

    Eap S

    2015-02-01

    Full Text Available Sandy Eap,1,2,* Laetitia Keller,1–3,* Jessica Schiavi,1,2 Olivier Huck,1,2 Leandro Jacomine,4 Florence Fioretti,1,2 Christian Gauthier,4 Victor Sebastian,1,3,5 Pascale Schwinté,1,2 Nadia Benkirane-Jessel1,21INSERM, UMR 1109, Osteoarticular and Dental Regenerative Nanomedicine Laboratory, FMTS, Faculté de Médecine, Strasbourg, France; 2Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France; 3Department of Chemical Engineering, Aragon Nanoscience Institute, University of Zaragoza, Zaragoza, Spain; 4CNRS (National Center for Scientific Research, ICS (Charles Sadron Institute, Strasbourg, France; 5Networking Research Center of Bioengineering, Biomaterials and Nanomedicine, Zaragoza, Spain*These authors contributed equally to this workAbstract: New-generation implants focus on robust, durable, and rapid tissue regeneration to shorten recovery times and decrease risks of postoperative complications for patients. Herein, we describe a new-generation thick nanofibrous implant functionalized with active containers of growth factors and stem cells for regenerative nanomedicine. A thick electrospun poly(ε-caprolactone nanofibrous implant (from 700 µm to 1 cm thick was functionalized with chitosan and bone morphogenetic protein BMP-7 as growth factor using layer-by-layer technology, producing fish scale-like chitosan/BMP-7 nanoreservoirs. This extracellular matrix-mimicking scaffold enabled in vitro colonization and bone regeneration by human primary osteoblasts, as shown by expression of osteocalcin, osteopontin, and bone sialoprotein (BSPII, 21 days after seeding. In vivo implantation in mouse calvaria defects showed significantly more newly mineralized extracellular matrix in the functionalized implant compared to a bare scaffold after 30 days’ implantation, as shown by histological scanning electron microscopy/energy dispersive X-ray microscopy study and calcein injection. We have as well bifunctionalized our BMP-7

  8. The estrogen receptor-alpha in osteoclasts mediates the protective effects of estrogens on cancellous but not cortical bone.

    Science.gov (United States)

    Martin-Millan, Marta; Almeida, Maria; Ambrogini, Elena; Han, Li; Zhao, Haibo; Weinstein, Robert S; Jilka, Robert L; O'Brien, Charles A; Manolagas, Stavros C

    2010-02-01

    Estrogens attenuate osteoclastogenesis and stimulate osteoclast apoptosis, but the molecular mechanism and contribution of these effects to the overall antiosteoporotic efficacy of estrogens remain controversial. We selectively deleted the estrogen receptor (ER)alpha from the monocyte/macrophage cell lineage in mice (ERalpha(LysM)(-/-)) and found a 2-fold increase in osteoclast progenitors in the marrow and the number of osteoclasts in cancellous bone, along with a decrease in cancellous bone mass. After loss of estrogens these mice failed to exhibit the expected increase in osteoclast progenitors, the number of osteoclasts in bone, and further loss of cancellous bone. However, they lost cortical bone indistinguishably from their littermate controls. Mature osteoclasts from ERalpha(LysM)(-/-) were resistant to the proapoptotic effect of 17beta-estradiol. Nonetheless, the effects of estrogens on osteoclasts were unhindered in mice bearing an ERalpha knock-in mutation that prevented binding to DNA. Moreover, a polymeric form of estrogen that is not capable of stimulating the nuclear-initiated actions of ERalpha was as effective as 17beta-estradiol in inducing osteoclast apoptosis in cells with the wild-type ERalpha. We conclude that estrogens attenuate osteoclast generation and life span via cell autonomous effects mediated by DNA-binding-independent actions of ERalpha. Elimination of these effects is sufficient for loss of bone in the cancellous compartment in which complete perforation of trabeculae by osteoclastic resorption precludes subsequent refilling of the cavities by the bone-forming osteoblasts. However, additional effects of estrogens on osteoblasts, osteocytes, and perhaps other cell types are required for their protective effects on the cortical compartment, which constitutes 80% of the skeleton.

  9. Eldecalcitol improves mechanical strength of cortical bones by stimulating the periosteal bone formation in the senescence-accelerated SAM/P6 mice - a comparison with alfacalcidol.

    Science.gov (United States)

    Shiraishi, Ayako; Sakai, Sadaoki; Saito, Hitoshi; Takahashi, Fumiaki

    2014-10-01

    Eldecalcitol (ELD), a 2β-hydroxypropyloxy derivative of 1α,25(OH)2D3, is a potent inhibitor of bone resorption that has demonstrated a greater effect at reducing the risk of fracture in osteoporotic patients than alfacalcidol (ALF). In the present study, we used the senescence-accelerated mouse strain P6 (SAM/P6), which has low bone mass caused by osteoblast dysfunction, to evaluate the effect of ELD on cortical bone in comparison with ALF. Four-month-old SAM/P6 mice were given either ELD (0.025 or 0.05μg/kg) or ALF (0.2 or 0.4μg/kg) by oral gavage 5 times/week for 6 weeks. Both ELD and ALF increased serum calcium (Ca) in a dose-dependent manner. Serum Ca levels in the ELD 0.05μg/kg group were comparable to those of the ALF 0.2μg/kg group. ELD 0.05μg/kg significantly improved the bone biomechanical properties of the femur compared with the vehicle control group (pBone histomorphometry revealed that in the femoral endocortical surface, the suppression of bone resorption parameters (N.Oc/BS) and bone formation parameters (MS/BS) by ELD (0.05μg/kg) was greater than that by ALF (0.2μg/kg). In contrast, in the femoral periosteal surface, ELD 0.05μg/kg significantly increased bone formation parameters (BFR/BS, MS/BS) compared with the vehicle control group (pbone not only by inhibiting endocortical bone resorption but also by stimulating the periosteal bone formation in SAM/P6 mice. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.

  10. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects.

    Science.gov (United States)

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-19

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100-150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1-10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

  11. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

    Science.gov (United States)

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100–150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1–10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

  12. Ultrasonic imaging of foreign inclusions and blood vessels through thick skull bones.

    Science.gov (United States)

    Shapoori, Kiyanoosh; Sadler, Jeffrey; Ahmed, Zaki; Wydra, Adrian; Maeva, Elena; Malyarenko, Eugene; Maev, Roman

    2015-03-01

    We report a new progress in the development of a portable ultrasonic transcranial imaging system, which is expected to significantly improve the clinical utility of transcranial diagnostic ultrasound. When conventional ultrasonic phased array and Doppler techniques are applied through thick skull bones, the ultrasound field is attenuated, deflected, and defocused, leading to image distortion. To address these deficiencies, the ultrasonic transcranial imaging system implements two alternative ultrasonic methods. The first method improves detection of small foreign objects, such as bone fragments, pieces of shrapnel, or bullets, lodged in the brain tissue. Using adaptive beamforming, the method compensates for phase aberration induced by the skull and refocuses the distorted ultrasonic field at the desired location. The second method visualizes the blood flow through intact human skull using ultrasonic speckle reflections from the blood cells, platelets, or contrast agents. By analyzing these random temporal changes, it is possible to obtain 2D or 3D blood flow images, despite the adverse influence of the skull. Both methods were implemented on an advanced open platform phased array controller driving linear and matrix array probes. They were tested on realistic skull bone and head phantoms with foreign inclusions and blood vessel models.

  13. Effect of rhythmic gymnastics on volumetric bone mineral density and bone geometry in premenarcheal female athletes and controls.

    Science.gov (United States)

    Tournis, S; Michopoulou, E; Fatouros, I G; Paspati, I; Michalopoulou, M; Raptou, P; Leontsini, D; Avloniti, A; Krekoukia, M; Zouvelou, V; Galanos, A; Aggelousis, N; Kambas, A; Douroudos, I; Lyritis, G P; Taxildaris, K; Pappaioannou, N

    2010-06-01

    Weight-bearing exercise during growth exerts positive effects on the skeleton. Our objective was to test the hypothesis that long-term elite rhythmic gymnastics exerts positive effects on volumetric bone mineral density and geometry and to determine whether exercise-induced bone adaptation is associated with increased periosteal bone formation or medullary contraction using tibial peripheral quantitative computed tomography and bone turnover markers. We conducted a cross-sectional study at a tertiary center. We studied 26 elite premenarcheal female rhythmic gymnasts (RG) and 23 female controls, aged 9-13 yr. We measured bone age, volumetric bone mineral density, bone mineral content (BMC), cortical thickness, cortical and trabecular area, and polar stress strength index (SSIp) by peripheral quantitative computed tomography of the left tibia proximal to the distal metaphysis (trabecular) at 14, 38 (cortical), and 66% (muscle mass) from the distal end and bone turnover markers. The two groups were comparable according to height and chronological and bone age. After weight adjustment, cortical BMC, area, and thickness at 38% were significantly higher in RG (P < 0.005-0.001). Periosteal circumference, SSIp, and muscle area were higher in RG (P < 0.01-0.001). Muscle area was significantly associated with cortical BMC, area, and SSIp, whereas years of training showed positive association with cortical BMC, area, and thickness independent of chronological age. RG in premenarcheal girls may induce positive adaptations on the skeleton, especially in cortical bone. Increased duration of exercise is associated with a positive response of bone geometry.

  14. Altered Cortical Thickness and Tract Integrity of the Mirror Neuron System and Associated Social Communication in Autism Spectrum Disorder.

    Science.gov (United States)

    Chien, Hsiang-Yun; Gau, Susan Shur-Fen; Hsu, Yung-Chin; Chen, Yu-Jen; Lo, Yu-Chun; Shih, Yao-Chia; Tseng, Wen-Yih Isaac

    2015-12-01

    Previous studies using neural activity recording and neuroimaging techniques have reported functional deficits in the mirror neuron system (MNS) for individuals with autism spectrum disorder (ASD). However, a few studies focusing on gray and white matter structures of the MNS have yielded inconsistent results. The current study recruited adolescents and young adults with ASD (aged 15-26 years) and age-matched typically developing (TD) controls (aged 14-25 years). The cortical thickness (CT) and microstructural integrity of the tracts connecting the regions forming the classical MNS were investigated. High-resolution T1-weighted imaging and diffusion spectrum imaging were performed to quantify the CT and tract integrity, respectively. The structural covariance of the CT of the MNS regions revealed a weaker coordination of the MNS network in ASD. A strong correlation was found between the integrity of the right frontoparietal tracts and the social communication subscores measured by the Chinese version of the Social Communication Questionnaire. The results showed that there were no significant mean differences in the CTs and tract integrity between the ASD and TD groups, but revealed a moderate or even reverse age effect on the frontal MNS structures in ASD. In conclusion, aberrant structural coordination may be an underlying factor affecting the function of the MNS in ASD patients. The association between the right frontoparietal tracts and social communication performance implies a neural correlate of communication processing in the autistic brain. This study provides evidence of abnormal MNS structures and their influence on social communication in individuals with ASD.

  15. Relation between intima-media thickness and bone mineral density in postmenopausal women: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Daniela Fodor

    Full Text Available CONTEXT AND OBJECTIVES: Controversy exists regarding the relationship between atherosclerosis and osteoporosis. The aim of this study was to determine the relationship between intima-media thickness (IMT of the common carotid artery (CCA, presence of calcified atherosclerotic plaques and bone mineral density (BMD evaluated by dual energy X-ray absorptiometry (DXA, in postmenopausal women. DESIGN AND SETTING: Cross-sectional study at Second Internal Medicine Clinic, Cluj-Napoca, Romania. METHODS: We studied the IMT (left and right CCA and mean IMT and T-score (lumbar spine L2-L4, femoral neck and total hip in 100 postmenopausal women (mean age 64.5 years. The presence of calcified atherosclerotic plaque and osteoporotic vertebral fractures was also noted. RESULTS: IMT in the left and right CCA and mean IMT were significantly associated with T-score measured for the lumbar spin