Higher Bone Density Research Articles

Predicting the bending properties of long bones: Insights from an experimental mouse model.

Analyses of bone cross-sectional geometry are frequently used by anthropologists and paleontologists to infer the loading histories of past populations. To address some underlying assumptions, we investigated the relative roles of genetics and exercise on bone cross-sectional geometry and bending mechanics in three mouse strains: high bone density (C3H/He), low bone density (C57BL/6), and a high-runner strain homozygous for the Myh4Minimsc allele (MM). Weanlings of each strain were divided into exercise (wheel) or control (sedentary) treatment groups for a 7-week experimental period. Morphometrics of the femoral mid-diaphysis and mechanical testing were used to assess both theoretical and ex vivo bending mechanics. Across all measured morphological and bending traits, we found relatively small effects of exercise treatment compared to larger and more frequent interstrain differences. In the exercised group, total distance run over the experimental period was not a predictor of any morphological or bending traits. Cross-sectional geometry did not accurately predict bone response to loading. Results from this experimental model do not support hypothesized associations among extreme exercise, cross-sectional geometry, and bending mechanics. Our results suggest that analysis of cross-sectional geometry alone is insufficient to predict loading response, and questions the common assumption that cross-sectional geometry differences are indicative of differential loading history.

The role of amylin in the development of diabetic osteopathy

Diabetes mellitus adversely affects the bone. Basically, it is related to weakening of the anabolic effect of insulin and other pancreatic hormones. Mechanisms underlying the decrease in bone density are not fully understood. However, many of the systemic changes related to metabolic abnormalities in diabetes have a damaging effect on the bone tissue. Inadequate compensation of glycemic profile in this disease, both directly (non-enzymatic glycosylation of proteins, activation of polyol pathway of glucose metabolism, oxidative stress) and indirectly (violation of gene expression), damages the bone structure. Another anabolic hormone produced by β-cells of the pancreas is amylin. It is a potent hypoglycemic and antiresorptive hormone affecting calcium homeostasis and influencing the preservation of bone density. The studies have shown that amylin, on the one hand, stimulates osteoblast proliferation, and on the other hand, inhibits osteoclast motility, thus acting similar to calcitonin. Inefficient redistribution of bone mass occurs. This may explain the increased incidence of fractures in patients with type 2 diabetes on the background of high bone density according to densitometry. In this regard, further studies are required to clarify the effect of amylin deficiency on the development of osteoporosis.

Bone Health of Young Male Gymnasts: A Systematic Review.

To synthesize existing literatures on the impact of gymnastics participation on the skeletal health of young male gymnasts. Following a systematic search, 12 studies were included in this review. Quality of included studies was assessed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE modified) criteria. Assessment of skeletal health varied between and within imaging modality protocols. Gymnasts had higher total bone content, greater total and trabecular bone density, larger bone size, a thicker cortex, and higher estimates of bone strength than controls. Recreational studies reported no difference in height or weight between gymnasts and controls; however, elite gymnasts were shorter and lighter than nongymnasts. STROBE scores ranged from 65% to 95%. Gymnastics participation may be beneficial to the bone health of young males as gymnasts had higher bone density and bone mineral content, larger bones, and greater estimates of bone strength than controls.

Biomechanical analysis of an interference screw and a novel twist lock screw design for bone graft fixation

BackgroundMalpositioning of an anterior cruciate ligament graft during reconstruction can occur during screw fixation. The purpose of this study is to compare the fixation biomechanics of a conventional interference screw with a novel Twist Lock Screw, a rectangular shaped locking screw that is designed to address limitations of graft positioning and tensioning. MethodsSynthetic bone (10, 15, 20lb per cubic foot) were used simulating soft, moderate, and dense cancellous bone. Screw push-out and graft push-out tests were performed using conventional and twist lock screws. Maximum load and torque of insertion were measured. FindingsMax load measured in screw push out with twist lock screw was 64%, 60%, 57% of that measured with conventional screw in soft, moderate and dense material, respectively. Twist lock max load was 78% and 82% of that with conventional screw in soft and moderate densities. In the highest bone density, max loads were comparable in the two systems. Torque of insertion with twist lock was significantly lower than with conventional interference screw. InterpretationBased on geometric consideration, the twist lock screw is expected to have 35% the holding power of a cylindrical screw. Yet, results indicate that holding power was greater than theoretical consideration, possibly due to lower friction and lower preloaded force. During graft push out in the densest material, comparable max loads were achieved with both systems, suggesting that fixation of higher density bone, which is observed in young athletes that require reconstruction, can be achieved with the twist lock screw.

Hypogonadal Men with Higher Body Mass Index have Higher Bone Density and Better Bone Quality but Reduced Muscle Density.

Although hypogonadism is a risk factor for bone loss and fractures, the different etiopathophysiology and hormonal profile of classical and obesity-induced hypogonadism may lead to differences in musculoskeletal profile. This is a cross-sectional study of hypogonadal men between 40 and 74years old. Our outcomes include: areal bone mineral density (aBMD) and body composition by dual-energy X-ray absorptiometry; volumetric BMD (vBMD) and soft tissue composition of the tibia by peripheral quantitative computed tomography. Fracture risk assessment tool (FRAX) scores were evaluated. Testosterone, estradiol, luteinizing hormone, follicle stimulating hormone, sex hormone-binding globulin, C-telopeptide, osteocalcin, and sclerostin were measured. We divided the population into subgroups of BMI: group 1: BMI<30; group 2: BMI≥30 to <35 and group 3: BMI≥35kg/m2. One-hundred five men were enrolled. Spine and hip aBMD, and total and trabecular vBMD at the 4% tibia significantly increased with increasing BMI. Cortical thickness (330.7±53.2, 343.3±35.4, and 358.7±38.2mm, p=0.04; groups 1, 2 and 3, respectively) and cortical area (5.3±0.7, 5.5±0.6, and 5.7±0.6mm, p=0.01; groups 1, 2 and 3, respectively) at 38% tibia increased with increasing BMI. While absolute lean mass increased with increasing BMI, % lean mass and muscle density (70.2±5.0, 71.3±6.4, and 67.1±5.1mg/cm3; groups 1, 2 and 3, respectively) were lowest in group 3. Although severely obese hypogondal men have better BMD and bone quality, they have reduced muscle density, the significance of which remains to be determined.

A descriptive study of bone density based on angle’s malocclusion classification on female patients aged 13–30 years old on panoramic radiograph

Objective: This study was performed to determine the bone density based on angle’s malocclusion classification on female patients aged 13–30 years old using panoramic radiograph.Material and Methods: Ninety digital panoramic radiographs of female patients aged 13–30 years old and with 30 radiographs representing each of the angle’s malocclusion classes (class I, class II, class III) were used. The bone density was measured by using ImageJ software with 20 x 20 pixels intensity by using a method based on the mental index (MI).Results: The mean bone density of female patients aged 13–30 years old with angle’s malocclusion of class I was 18.726% of cortical and 81.274% of marrow, class II was 16.804% of cortical and 83.196% of marrow, and class III was 15.911% of cortical and 84.089% of marrow.Conclusion: The bone density of female patients aged 13–30 years old with angle’s class I malocclusion was higher than class II and class II malocclusion had higher bone density than class III on panoramic radiograph.

Reverse total shoulder glenoid baseplate stability with superior glenoid bone loss

Superior wear of the glenoid bone is common in patients with rotator cuff arthropathy. This can become a treatment challenge for patients who require shoulder arthroplasty. In reverse shoulder arthroplasty (RSA), glenoid bone loss may affect the stability of baseplate fixation. The primary purpose of this biomechanical laboratory study was to assess the initial fixation stability of RSA glenosphere baseplates in the presence of variable amounts of superior glenoid bone loss. High-density solid rigid polyurethane foam (30 pounds/cubic foot) was machined to model the glenoid with variable superior defects that provided different levels of support (100%, 90%, 75%, and 50%) for the glenosphere baseplate. The samples were cyclically loaded (0-750 N at 1 Hz for 5000 cycles) at a 60° glenohumeral angle. The micromotion and migration of the baseplate were calculated from displacement data captured during the loading tests with an array of 3 linear variable differential transformers mounted around the baseplate. Micromotion was significantly greater in samples with 50% defects compared with those with smaller defects. Migration was significantly greater after testing for all defect sizes. Initial fixation of RSA glenosphere baseplates was significantly reduced in models with 50% bone loss on the superior edge compared with models with less bone loss in this high-density bone foam model.

Comparison of bone metabolism based on the different ages and competition levels of junior and high school female rhythmic gymnasts.

[Purpose]This study was to clarify the effect of age and competition level by measuring bone metabolism markers and bone mineral density measurements of junior high school and high school female rhythmic gymnasts, who restrict their diets to maintain a low body weight, while routinely undertaking long hours of high-intensity exercise, comparing the gymnasts based on their elite/non-elite. [Methods]The study investigated 7 junior high school and 12 high school female rhythmic gymnasts. For comparison by competition level, the 7 junior high school gymnasts were separated into 3 gymnasts who competed at national level (junior high school elite), and 4 gymnasts who did not compete at that level (junior high school non-elite), and the 12 high school gymnasts were separated into 7 gymnasts who competed at national level (high school elite) and 5 gymnasts who did not compete at that level (high school non-elite). The measurement items were bone mineral density, bone metabolism markers (undercarboxylated osteocalcin (ucOC), osteocalcin (OC), bone-specific alkaline phosphatase (BAP), calcium (Ca), inorganic phosphorus (P), alkaline phosphatase (ALP), parathyroid hormone (PTH), type 1 collagen cross-linked N-telopeptide (NTx)). We also surveyed the gymnasts’ height, weight and nutrition. [Results]In this study we found: 1) The high school gymnasts who competed at high-level rhythmic gymnastics had good results for bone metabolism markers and bone mineral density. 2) Elite high school gymnasts had restricted diets. 3) Nutritionally, their energy intake and carbohydrate intake was low, but their intake of protein, calcium, iron, vitamin D and vitamin K was good. [Conclusion]The results found that the elite gymnastics showed a higher bone density than the non-elite group that suggests the possibility of inhibiting bone formation in the bone metabolism.

Spatial mapping of humeral head bone density

BackgroundShort-stem humeral replacements achieve fixation by anchoring to the metaphyseal trabecular bone. Fixing the implant in high-density bone can provide strong fixation and reduce the risk of loosening. However, there is a lack of data mapping the bone density distribution in the proximal humerus. The aim of the study was to investigate the bone density in proximal humerus.MethodsEight computed tomography scans of healthy cadaveric humeri were used to map bone density distribution in the humeral head. The proximal humeral head was divided into 12 slices parallel to the humeral anatomic neck. Each slice was then divided into 4 concentric circles. The slices below the anatomic neck, where short-stem implants have their fixation features, were further divided into radial sectors. The average bone density for each of these regions was calculated, and regions of interest were compared using a repeated-measures analysis of variance with significance set at P < .05.ResultsAverage apparent bone density was found to decrease from proximal to distal regions, with the majority of higher bone density proximal to the anatomic neck of the humerus (P < .05). Below the anatomic neck, bone density increases from central to peripheral regions, where cortical bone eventually occupies the space (P < .05). In distal slices below the anatomic neck, a higher bone density distribution in the medial calcar region was also observed.ConclusionThis study indicates that it is advantageous with respect to implant fixation to preserve some bone above the anatomic neck and epiphyseal plate and to use the denser bone at the periphery.

51 - BonoFillTM – a novel treatment for maxillofacial bone tissue regeneration

Over recent years, we have developed a three-dimensional, high-density bone graft designed to overcome the limitations associated with current bone reconstruction treatments. The graft, named BonoFillTM, is generated from the patients' adipose tissue-derived cells, and consists of a heterogeneous cell population, providing superior osteinductive properties and promoting graft integration and de novo bone formation. Produced in Bonus Biogroup's GMP-certified clean room facility, BonoFillTM represents a potent therapeutic modality for bone repair.

Autogenous bone harvesting from iliac crest and symphysis for implant reconstruction

Horizontal and vertical bone resorption may be seen after tooth loss in the maxilla and mandible. The deficient edentulous ridge may interfere with the insertion of implants of adequate length placed in the correct position and with the ideal inclination. The severe alveolar bone resorption or pneumatisation of the maxillary sinus makes it difficult to perform the conventional dental implantation procedure. Functional implant-supported oral rehabilitation is increasingly being used as a restoration strategy for fully and partially edentulous patients, whenever sufficient bone volume is available. Implant-supported restoration is possible even in severely resorbed jaws using a reconstruction technique with bone augmentation that includes vascularised or nonvascularised bone grafting and tissue regeneration techniques. Standard donor sites for free autogenous bone-graft techniques are: the chin or ramus mandible, the iliac crest, the tibia and the calvaria. Advantages of intraoral mandibular sources include easy access, low morbidity, short healing periods, minimal graft resorption, and maintenance of high bone density; side effects include possible postoperative sensory disturbances and discomfort. Calvaria and iliac crest donor areas are most commonly used in cases of extensive alveolar ridge augmentation. The iliac crest generally supplies large quantities of corticocancellous bone. In this report, we present autogenous bone graft harvesting of 48 patients (40 iliac anterior crest, 8 symphysis) for facial reconstructive surgery.

Effect That Lifestyle during the Growth Period Has on Bone Density Acquisition—Using Simple Exercise and a Nutrition Survey

This survey was conducted with the aim of clarifying and providing guidance regarding correct lifestyle and exercise habits from adolescence in order to prevent the development of osteoporosis. The subjects included 195 Japanese adult females. We measured their calcaneal bone density by ultrasonography, the index of which was determined as SOS (Speed of Sound). We examined their physical characteristics, health conditions, amount of physical activity, exercise history, and eating habits, and then analyzed the relationship thereof with bone density. No significant correlation was found between height, weight, BMI (Body Mass Index), or body fat percentage and the SOS value. Moreover, the bone density among those with a history of exercise was high. Breaking it down, we obtained results such as the fact that exercise habits during the junior and senior high school years had a great impact on the acquisition of peak bone mass, although no relationship between exercise habits and bone density was found during the elementary school years. Furthermore, as the bone density of students who continued exercising in junior and senior high school indicated high values, continuity of exercise during the growth period (during puberty) is believed to have a great impact on peak bone mass. Upon investigating the content of meals including foods which have a positive impact on the bones, “bean and bean products” and “green and yellow vegetables” were found to be related to bone density. From the above, the effect that the lifestyle of young adult females had on bone density was partially clarified. In particular, one factor which had a strong relationship with current bone density was exercise history during the junior and senior high school periods. It was clarified that continuously engaging in exercise and placing strain on the bones during these periods lead to high bone density acquisition.

Relationship of Physical Activity Type, Nutrition, and Bone Mineral Density in Korean Adolescents

Background and Objective Bone density reaches its peak in the mid-20s and manifests as osteoporosis and osteopenia with aging. Bone density is affected by body mass index, muscle mass, nutritional calcium and vitamin D, as well as Lifestyle, type and duration of physical activity, and level of physical strength. The purpose of this study was to investigate the difference in diet and bone density according to physical activity level in growing male and female adolescents. Material and Methods This study involved 646 male and 581 female adolescents using data from the Korea National Health and Nutrition Examination in 2009-2011. The measurement of bone density consisted of dual-energy X-ray absorptiometry, and was classified into low-, middle-, and high-density groups at different ages based on total bone mineral density. The Korean version of the International Physical Activity Questionnaire by the World Health Organization was used to measure physical activity level, and a survey regarding strength, exercise, and stretching was conducted. In the nutritional survey, data from a 24-hour recall were analyzed. One-way analysis of variance and chi-square tests were conducted to examine the presence and significance of any differences. Results Even though there was no difference among groups in both males and females, there was a significant difference in weight (p 0.05). In males, the high-density group showed significantly higher intake of calories (p=0.032), protein (p=0.015), calcium (p=0.043), and phosphorus (p=0.013) compared with the low group. There was a significant difference in bone density related to physical activity level. In the low and high bone density groups, the proportion of strength exercises increased to more than 3 times a week was 18.1% and 27.2%, respectively in males (p=0.046), and was 1.0% and 6.1% respectively in females (p=0.014). The proportion of high-intensity exercise 6–7 times a week also showed a significant difference as the low, middle, and high bone density groups showed 5.1%, 5.5%, and 14.1%, respectively (p<0.001). Conclusion Among adolescents, bone density in females was affected by strength exercise, and bone density in males was affected by physical activity level and nutrition, showing a clearer tendency in the males. Particularly, regarding physical activity level, high intensity and strength exercise had more positive effects.

Valor pronóstico de la densidad ósea y de la movilidad en el éxito implantológico

PurposesTo prospectively analyze the prognosis value of the primary mobility (at the moment of implant insertion) and secondary (prosthetic phase), as well as bone density, in the implant success or failure after one year, five years and ten years. Materials and methodsBetween 2005 and 2006, 151 implants were placed in 71 non-smoking patients. Primary (at the moment of surgery) and secondary (once osseointegrated) stabilities were measured in each implant through a Periotest® value (PTV) and the bone density was scored at the moment of implantation. One hundred nine of 151 implants placed initially completed the study. ResultsThere were no statistically significant differences regarding implant mobility at the moment of its insertion or once osseointegrated and the implant success or failure after 10 years. However, statistically significant differences were found respect to the bone density where the implant was placed after 5 and 10 years (P<.05). ConclusionsPrimary or secondary mobility of the implant has no significant prognosis value on the implant success after 10 years. On the other hand, bone density has a clear influence on long time implant success. High density bones are more predictable to fail than low density bones after a long time.

Improving tribological and anti-bacterial properties of titanium external fixation pins through surface ceramic conversion

In this study, an advanced ceramic conversion surface engineering technology has been applied for the first time to self-drilling Ti6Al4V external fixation pins to improve their performance in terms of biomechanical, bio-tribological and antibacterial properties. Systematic characterisation of the ceramic conversion treated Ti pins was carried out using Scanning electron microscope, X-ray diffraction, Glow-discharge optical emission spectroscopy, nano- and micro-indentation and scratching; the biomechanical and bio-tribological properties of the surface engineered Ti pins were evaluated by insertion into high density bone simulation material; and the antibacterial behaviour was assessed with Staphylococcus aureus NCTC 6571. The experimental results have demonstrated that the surfaces of Ti6Al4V external fixation pins were successfully converted into a TiO2 rutile layer (~2 μm in thickness) supported by an oxygen hardened case (~15 μm in thickness) with very good bonding due to the in-situ conversion nature. The maximum insertion force and temperature were reduced from 192N and 31.2 °C when using the untreated pins to 182N and 26.1 °C when the ceramic conversion treated pins were tested. This is mainly due to the significantly increased hardness (more than three times) and the effectively enhanced wear resistance of the cutting edge of the self-drilling Ti pins following the ceramic conversion treatment. The antibacterial tests also revealed that there was a significantly reduced number of bacteria isolated from the ceramic conversion treated pins compared to the untreated pins of around 50 % after 20 h incubation, P < 0.01 (0.0024). The results reported are encouraging and could pave the way towards high-performance anti-bacterial titanium external fixation pins with reduced pin-track infection and pin loosing.

Conversations between insulin and bone: Potential mechanism of high bone density in patients with Berardinelli-Seip Congenital Lipodystrophy

Berardinelli-Seip Congenital Lipodystrophy (BSCL) is a rare autosomal recessive syndrome characterized by a difficulty storing lipid in adipocytes, low body fat, hypertriglyceridemia, and fat liver. The serum leptin is usually very low, and serum insulin, as well as HOMAIR (homeostasis model assessment), is very high and correlated positively with bone mineral density (BMD). Despite deficiency/insufficiency of vitamin D, low body mass index, low daily calcium intake, physical inactivity, and menarche at a later age, BSCL patients usually have normal or even high BMD. We hypothesize that low leptin and high insulin may play a role in this outcome. Understanding the potential pathophysiological mechanism of these bone abnormalities will help to clarify the effects of extreme insulin resistance in the bone.

Abstract 1692: Role of snail in cancer-bone microenvironment interactions

Abstract Prostate Cancer (PCa) is the second leading cause of cancer death in American men and African Americans are twice as likely to get PCa as their Caucasian counterparts. As with most forms of cancer, PCa patients’ mortality is mainly attributed to complications caused by metastasis of the disease to organs critical for survival such as bone. As such, it is important to understand cancer-bone microenvironment interactions in order to develop therapeutics that will slow or halt the process of cancer metastasis. It is also known that African Americans have a higher bone mineral density compared to any other race. Snail1 is a zinc-finger transcription factor that induces epithelial-mesenchymal transition (EMT) which is associated with cell migration and metastasis in cancer cells. In preliminary studies, cancer cells co-cultured with bovine bone discs led to increased calcium release that was higher in cancer cells overexpressing Snail, as well as in bone discs of higher density. We hypothesized that cancer cell-bone interactions would promote higher calcium release from bone by cancer cells overexpressing Snail, which would lead to increased paracrine cell migration. For this study, we utilized prostate (ARCaP) or breast (MCF-7) cancer cells stably overexpressing Snail as well as prostate (C4-2) cancer cells with stable Snail knockdown. Cancer cells were co-cultured with bovine bone disc or Hydroxyapatite (HA; inorganic component of bone) of different densities to represent the African American vs Caucasian bone ratio. The conditioned media was then used for to assay calcium levels, test paracrine cell viability and migration assays using C4-2 parental cells. We observed that calcium levels were elevated in conditioned media from cancer cell-bone co-cultures, compared to media alone or media plus bone, and this could be antagonized by EGTA, a calcium chelator. It was increased with higher bone density as well as with bone co-cultured with MCF-7-Snail, ARCaP-Snail and C4-2 cancer cells as compared to MCF-7 Neo, ARCaP-Neo or C4-2 with Snail knockdown. When we utilized the conditioned media for a paracrine cell viability assay, there was no significant differences. However, C4-2 cancer-bone co-culture conditioned media increased paracrine cell migration which was decreased by Snail knockdown as well as lower bone density. Hence Snail expressing PCa cells co-cultured with HA led to increased paracrine cell migration. We are currently studying the signaling mechanism(s) involved in this cancer-bone interactions. In conclusion, our study shows that Snail can mediate cancer-bone microenvironment interactions that can possibly promote increased cell migration towards bone of high mineral density such as is found in African Americans. GRANT SUPPORT: 1P20MD002285 Citation Format: Veronica M. Henderson, Liza J. Burton, Simone M. Howard, Valerie A. Odero-Marah. Role of snail in cancer-bone microenvironment interactions. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1692.

Bone-Albumin filling decreases donor site morbidity and enhances bone formation after anterior cruciate ligament reconstruction with bone-patellar tendon-bone autografts.

Donor site pain affects 32-43% of patients after anterior cruciate ligament surgery when the autograft is freshly harvested bone-patellar tendon-bone tissue. Our aim was to compare functional and morphological differences between donor sites with and without serum albumin-coated bone allograft filling. After harvesting and implanting the graft, the tibia site was filled with either fresh autologous cancellous bone enhanced with albumin-coated allograft or autologous bone alone. The patella site was filled either with albumin-coated allograft or with blood clot. Knee function was evaluated by the VISA, Lysholm and IKDC scores and a visual analog scale of pain during standing, kneeling and crouching after sixweeks and sixmonths. Computed tomography was performed at sixmonths for morphological evaluation. At sixweeks, both groups were still recovering from surgery and the overall knee function was still impaired but the functional scores were significantly higher in the Bone-Albumin group. The pain with crouching and kneeling was also lower as compared to controls. At sixmonths, the knee function scores were close to normal, with a slight decrease in the controls. Pain at kneeling was still prominent in the controls, but significantly lower in the Bone-Albumin group. Computed tomography showed significantly smaller bone defects and higher bone density in the Bone-Albumin group. Results from the present study indicate that donor site pain, a disturbing long-term side effect of bone-patellar tendon-bone surgery, is significantly reduced if bone buildup in the patella and the tibia is augmented by serum albumin-coated bone allografts.

Mgat5 modulates the effect of early life stress on adult behavior and physical health in mice

Psychosocial adversity in early life increases the likelihood of mental and physical illness, but the underlying mechanisms are poorly understood. Mgat5 is an N-acetylglucosaminyltransferase in the Golgi pathway that remodels the N-glycans of glycoproteins at the cell surface. Mice lacking Mgat5 display conditional phenotypes in behaviour, immunity, metabolism, aging and cancer susceptibility. Here we investigated potential gene-environment interactions between Mgat5 and early life adversity on behaviour and physiological measures of physical health. Mgat5−/− mutant and Mgat5+/+ wild-type C57Bl/6 littermates were subject to maternal separation or foster rearing as an early life stressor, in comparison to control mice reared normally. We found an interaction between Mgat5 genotype and maternal rearing condition in which Mgat5−/− mice subjected to early life stress had lower glucose levels and higher bone density. Mgat5−/− genotype was also associated with less immobility in the forced swim test and greater sucrose consumption, consistent with a less depression-like phenotype. Cortical neuron dendrite spine density and branching was altered by Mgat5 deletion as well. In general, Mgat5 genotype affects both behaviour and physical outcomes in response to early life stress, suggesting some shared pathways for both in this model. These results provide a starting point for studying the mechanisms by which protein N-glycosylation mediates the effects of early life adversity.

Alveolar bone density and its clinical implication in the placement of dental implants and orthodontic mini-implants.

Objectives:To assess the bone density in maxilla and mandible in dentate and edentulous patients in Saudi population.Methods:This study involved a retrospective analysis of cone beam CT images of 100 patients (50 male and 50 female) who have come to College of Dentistry, University of Dammam, Dammam, Kingdom of Saudi Arabia between January 2014 and 2015. Using the bone density option in the Simplant software, the Hounsfield unit (HU) was calculated at the edentulous sites. While for dentate sites, a region of interest was selected coronally at 3-5 mm to the root apex using I-CAT vision software. The densities of the buccal bone and cancellous bone were measured at interradicular areas of a specific teeth.Results:The highest bone density at the edentulous sites was at the mandibular anterior region (776.5 ± 65.7 HU), followed by the mandibular posterior region (502.2 ± 224.2 HU). Regarding the dentate sites, the highest bone density was at the buccal cortical plate of the lower incisor teeth (937.56 ± 176.92 HU) and the lowest bone density was at the cancellous bone around the posterior maxillary teeth (247.12 ± 46.75 HU).Conclusion:The alveolar bone density at dentate and edentulous sites in our population is generally lower than the norm reference density of other populations, which dictates the need for quantitative assessment of bone density before implants and mini-implants placement.