Quantitative trait loci analysis of structural and material skeletal phenotypes in C57BL/6J and DBA/2 second-generation and recombinant inbred mice.

QTL analyses identified several chromosomal regions influencing skeletal phenotypes of the femur and tibia in BXD F2 and BXD RI populations of mice. QTLs for skeletal traits co-located with each other and with correlated traits such as body weight and length, adipose mass, and serum alkaline phosphatase. INTRODUCTION: Past research has shown substantial genetic influence on bone quality, and the impact of reduced bone mass on our aging population has heightened the interest in skeletal genetic research. MATERIALS AND METHODS: Quantitative trait loci (QTL) analyses were performed on morphologic measures and structural and material properties of the femur and tibia in 200-day-old C57BL/6J x DBA/2 (BXD) F2 (second filial generation; n = 400) and BXD recombinant inbred (RI; n = 23 strains) populations of mice. Body weight, body length, adipose mass, and serum alkaline phosphatase were correlated phenotypes included in the analyses. RESULTS: Skeletal QTLs for morphologic bone measures such as length, width, cortical thickness, and cross-sectional area mapped to nearly every chromosome. QTLs for both structural properties (ultimate load, yield load, or stiffness) and material properties (stress and straincharacteristics and elastic modulus) mapped to chromosomes 4, 6, 9, 12, 13, 15, and 18. QTLs that were specific to structural properties were identified on chromosomes 1, 2, 3, 7, 8, and 17, and QTLs that were specific to skeletal material properties were identified on chromosomes 5, 11, 16, and 19. QTLs for body size (body weight, body length, and adipose mass) often mapped to the same chromosomal regions as those identified for skeletal traits, suggesting that several QTLs identified as influencing bone could be mediated through body size. CONCLUSION: New QTLs, not previously reported in the literature, were identified for structural and material properties and morphological measures of the mouse femur and tibia. Body weight and length, adipose mass, and serum alkaline phosphatase were correlated phenotypes that mapped in close proximity of skeletal chromosomal loci. The more specific measures of bone quality included in this investigation enhance our understanding of the functional significance of previously identified QTLs.     

The Role of Donor Bone Marrow Infusions in Withdrawal of Immunosuppression in Adult Liver Allotransplantation

We investigated the role of donor bone marrow cell (DBMC) infusions in immunosuppression withdrawal in adult liver transplantation. Patients enrolled were at least 3 years post-transplantation, with stable graft function. Forty-five (study group: G1) received DBMC, and 59 (control group: G2) did not. Immunosuppression was reduced by one third upon enrollment, by another third the second year of the study and was completely withdrawn the third year. Patient and graft survival were similar between the two groups. Although rejection episodes were significantly less in G1 the first 2 years of the study (35% vs. 57%, p = 0.016), there was no significant difference overall (74% vs. 81%, p = 0.14). Until February 2004, 20 patients, 10 in each group, were immunosuppression free for 1-3 years. Approximately 20% of long-term survivors of liver transplantation can successfully discontinue their immunosuppression. DBMC infusions, do not increase this likelihood.     

Changes in bone structure after augmentation cystoplasty in chronic uraemic rats

OBJECTIVE: To investigate the effect of urinary diversion using several types of intestinal segments on cortical and cancellous bone structure of growing rats with renal insufficiency. MATERIAL AND METHODS: In all, 110 female Sprague-Dawley rats (8 weeks old) had either a two-stage subtotal nephrectomy by removing five-sixths of the renal mass, or a sham operation. Except for a uraemic control group, all uraemic rats then had an enterocystoplasty using stomach, ileum or colon (20 animals per group). An additional group with colic augmentation received the bisphosphonate ibandronate. After 12 weeks, the left tibia was assessed using peripheral quantitative computed tomography and bone histomorphometry. RESULTS: After subtotal nephrectomy all groups had approximately 30% less endogenous creatinine clearance. Renal failure alone or in association with gastric or colic augmentation induced only negligible changes in the mass and structure of cortical and cancellous tibial bone. In contrast, rats after ileal augmentation and renal failure had a significant reduction in cancellous bone mineral density (P < 0.05) whereas the reduction in trabecular bone area and volume was not statistically significant. Furthermore, ileocystoplasty caused a decrease in trabecular number and perimeter, increased trabecular separation and enlarged bone marrow space, whereas ileocystoplasty had no effect on cortical bone. The changes were not associated with alterations in serum pH. Ibandronate treatment in the colonic cystoplasty group increased trabecular bone mass and structural variables over the untreated colonic cystoplasty group. CONCLUSIONS: These results suggest that cystoplasty using an ileal segment causes a decrease in bone mass and architecture in growing rats with mild uraemia. It remains open to question whether the results obtained from experimental animals can be directly extrapolated to the clinical situation.     

Scaffolds for bone restoration from cuttlefish

Scaffolds of pure hydroxyapatite suitable for either direct clinical use or tissue-engineering applications were successfully produced via hydrothermal transformation of aragonite, obtained from fresh cuttlefish bones, at 200°C followed by sintering. Beyond low production cost, worldwide availability and natural–biological origin of raw materials, the produced scaffolds have ideal pore size and interconnectivity features suitable for supporting biological activities, such as bone tissue growth and vascularization. Bioactivity in vitro tests were excellent: (a) rapid and pronounced formation of hydroxyapatite occurred when the scaffolds were immersed in simulated body fluid (SBF), and (b) outstanding proliferation of osteoblasts was registered. The produced scaffolds can be machined and shaped very easily at any stage of processing. Therefore, these ceramic scaffolds can satisfy both bioactivity demands and the requirements for shaping of tailor-made individualized implants, especially for randomly damaged bones.     

Postmenopausal Women With Colles'' Fracture Have Lower Values of Bone Mineral Density Than Controls as Measured by Quantitative Ultrasound and Densitometry

Measurement of ultrasonographic parameters provides information concerning not only bone density but also bone architecture. We investigated the usefulness of ultrasonographic parameters and bone mineral density (BMD) to evaluate the probability of Colles' fracture. Two-hundred eighty-nine postmenopausal women (62.3 +/- 8.7 yr) with (n = 76) and without (n = 213) Colles' fracture were studied. BMD of lumbar spine and proximal femur was evaluated in all women by dual-energy X-ray absorptiometry (DXA) and speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness in the calcaneus were measured by a Sahara ultrasonometer (Hologic). Patients suffering from Colles' fracture had lower values of BMD adjusted by height at the lumbar spine, L2-L4 (0.797 g/cm2 vs 0.860 g/cm2), femoral neck (0.685 g/cm2 vs 0.712 g/cm2 ), SOS (1518 m/sg vs 1525 m/sg), and stiffness (74.6 vs 77.7) (p < 0.05). Nevertheless, BUA values were similar in both groups. After stepwise logistic regression analysis, the area found under receiver operating characteristic (ROC) curves was 0.60 for L2L4 and 0.63 for a formula combining L2L4 and height. Our data suggest that patients suffering from Colles' fracture have lower values of BMD by DXA, SOS, and stiffness. However, the ability of these techniques to discriminate is low because the values for the area under ROC curve are 0.60 for L2-L4 and 0.63 for a formula derived of the combination of L2-L4 and height.     

Improved Performance of Hip DXA Using a Novel Region of Interest in the Upper Part of the Femoral Neck: In Vitro Study Using Bone Strength as a Standard of Reference

We tested the hypothesis that bone mineral density (BMD) and bone mineral content (BMC) in proximal human femur specimens in the upper neck region of interest (ROI) and femoral neck axis length (FNAL) provide a significantly better prediction of femoral bone strength than standard ROIs in vitro. BMD and BMC were measured in 110 proximal femur specimens using a standard dual-energy X-ray absorptiometry (DXA) scanner. The analysis included a new ROI in the upper neck as well as the standard ROIs. FNAL was obtained from the scan images. The specimens' failure-load was measured in a mechanical loading device, simulating a fall on the greater trochanter. For the standard ROIs, correlations between failure-load and BMD ranged from R2 = 0.64 (shaft ROI) to R2 = 0.70, p < 0.001 (femoral neck). Prediction of strength by BMD did not significantly differ from those of BMC (R2 ranging from 0.65 to 0.75, p < 0.001). In the upper neck ROI, for both BMD and BMC correlations with failure-load were higher (R2 = 0.76 and 0.81, respectively; p < 0.001). A lower, yet still significant, correlation was found between FNAL and bone strength (R2 = 0.23, p < 0.001). Normalization of failure-load with respect to FNAL did not significantly increase the correlations with densitometric measures. This study provides in vitro evidence indicating that among the ROIs of the proximal femur the newly defined upper neck ROI provides the best prediction of bone strength. Only a weak association was observed between failure load and FNAL.     

Growth of bone marrow stromal cells on small intestinal submucosa: an alternative cell source for tissue engineered bladder

OBJECTIVE: To assess the potential use of bone marrow stromal cell (BMSC)-seeded biodegradable scaffold for bladder regeneration in a canine model, by characterizing BMSCs and comparing them to bladder smooth muscle cells (SMCs) by immunohistochemistry, growth capability, and contractility. MATERIALS AND METHODS: Bone marrow was taken by direct needle aspiration from the femurs of five beagle dogs for the in vitro study. Mononuclear cells were isolated by Ficoll-Paque density gradient centrifugation and cultivated in medium 199 with 10% fetal bovine serum. BMSCs were characterized by cell proliferation, in vitro contractility, immunohistochemical analysis, and the growth pattern on small intestinal submucosa (SIS) scaffolds compared to bladder SMC cultures from the same dogs. Another six dogs had a hemicystectomy and bladder augmentation with BMSC-seeded (two), bladder cells including urothelial cells plus SMC-seeded SIS (two) and unseeded SIS scaffolds (two). The six dogs were followed for 10 weeks after augmentation. RESULTS: In vitro BMSCs had a significant contractile response to calcium-ionophore, with a mean (sem) 36 (2)%, relative contraction (P < 0.01), which was similar to bladder SMCs but markedly different from fibroblasts. BMSCs also expressed alpha-smooth muscle actin by immunohistochemical staining and Western blotting, but did not express desmin or myosin. In vivo, both BMSC-seeded and bladder cell-seeded SIS grafts had solid smooth-muscle bundle formation throughout the graft. CONCLUSIONS: BMSCs had a similar cell proliferation, histological appearance and contractile phenotype as primary cultured bladder SMCs. SIS supported three-dimensional growth of BMSCs in vitro, and BMSC-seeded SIS scaffold promoted bladder regeneration in a canine model. BMSCs may serve as an alternative cell source in urological tissue engineering.     

Predictors of subsequent prostate cancer in men with a prostate specific antigen of 2.6 to 4.0 ng/ml and an initially negative biopsy

PURPOSE: Almost 75% of men with a prostate specific antigen (PSA) of 2.6 to 4.0 ng/ml have no evidence of prostate cancer on biopsy. Deciding whether and when to repeat the biopsy is challenging. We determined if patient specific variables might identify men at increased risk for the subsequent detection of prostate cancer. MATERIALS AND METHODS: We analyzed the records of 24,893 men from a community based prostate cancer screening study. Our study group consisted of 1,202 men with PSA 2.6 to 4.0 ng/ml and a previously negative prostate biopsy. Patient specific variables were analyzed for their value in predicting a future diagnosis of prostate cancer. RESULTS: Of 1,011 men with adequate followup 136 (13.5%) were subsequently diagnosed with prostate cancer. Mean followup +/- SD in men without prostate cancer was 72 +/- 36 months. Prostate cancer was subsequently diagnosed in 35% of men with high grade prostatic intraepithelial neoplasia (HGPIN) on initial biopsy (p <0.0001), in 18% with abnormal or suspicious digital rectal examination (DRE) (p = 0.02) and 16% with an annual PSA velocity of 0 ng/ml (p = 0.002). Multivariate analysis identified HGPIN, initial PSA 3.6 to 4.0 ng/ml, abnormal DRE, family history of prostate cancer and annual PSA velocity 0 ng/ml as predictors of prostate cancer. CONCLUSIONS: Men with a PSA of 2.6 to 4.0 ng/ml and negative biopsy should be advised to undergo repeat biopsy if they have HGPIN, initial PSA 3.6 to 4.0 ng/ml, abnormal DRE, a family history of prostate cancer or a PSA velocity of 0 ng/ml or greater.     

Free radical scavenging alleviates the biomechanical impairment of gamma radiation sterilized bone tissue.

Terminal sterilization of bone allografts by gamma radiation is often essential prior to their clinical use to minimize the risk of infection and disease transmission. While gamma radiation has efficacy superior to other sterilization methods it also impairs the material properties of bone allografts, which may result in premature clinical failure of the allograft. The mechanisms by which gamma radiation sterilization damages bone tissue are not well known although there is evidence that the damage is induced via free radical attack on the collagen. In the light of the existing literature, it was hypothesized that gamma radiation induced biochemical damage to bone's collagen that can be reduced by scavenging for the free radicals generated during the ionizing radiation. It was also hypothesized that this lessening of the extent of biochemical degradation of collagen will be accompanied by alleviation in the extent of biomechanical impairment secondary to gamma radiation sterilization. Standardized tensile test specimens machined from human femoral cortical bone and specimens were assigned to four treatment groups: control, scavenger treated-control, irradiated and scavenger treated-irradiated. Thiourea was selected as the free radical scavenger and it was applied in aqueous form at the concentration of 1.5 M. Monotonic and cyclic mechanical tests were conducted to evaluate the mechanical performance of the treatment groups and the biochemical integrity of collagen molecules were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The native mechanical properties of bone tissue did not change by thiourea treatment only. The effect of thiourea treatment on mechanical properties of irradiated specimens were such that the post-yield energy, the fracture energy and the fatigue life of thiourea treated-irradiated treatment group were 1.9-fold, 3.3-fold and 4.7-fold greater than those of the irradiated treatment group, respectively. However, the mechanical function of thiourea treated and irradiated specimens was not to the level of unirradiated controls. The damage occurred through the cleavage of the collagen backbone as revealed by SDS PAGE analysis. Irradiated specimens did not exhibit a noteworthy amount of intact alpha-chains whereas those irradiated in the presence of thiourea demonstrated intact alpha-chains. Results demonstrated that free radical damage is an important pathway of damage, caused by cleaving the collagen backbone. Blocking the activity of free radicals using the scavenger thiourea reduces the extent of damage to collagen, helping to maintain the mechanical strength of sterilized tissue. Therefore, free radical scavenger thiourea has the potential to improve the functional life-time of the allograft component following transplantation.     

Roux-en-Y胃旁路术治疗不同体质指数2型糖尿病的疗效及其对患者糖脂代谢的影响

目的：探讨Roux-en-Y胃旁路术(RYGB)治疗不同体质指数2型糖尿病的疗效及其对患者糖脂代谢的影响。方法选取2014年1月至2015年12月在涿州市医院外科接受Roux-en-Y胃旁路术治疗的2型糖尿病患者96例,根据体质量指数(BMI)不同分为高BMI组44例(BMI≥30.0 kg/m2)和低BMI组52例(BMI<30.0 kg/m2)。分别在术前及术后1个月、3个月、6个月、12个月检测两组患者的空腹血糖(FPG)、餐后2 h血糖(2 hPG)、糖化血红蛋白(HbA1c)、空腹C肽(FC-P)、总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)水平、体质量、腰围、BMI和用药情况,比较手术前后的各项指标。随访患者术后12个月的疗效及相关影响因素。结果高BMI组和低BMI组患者手术前,术后1个月、3个月、6个月及12个月的体质量、BMI、腰围的变化趋势比较,差异均无统计学意义(P>0.05);脂代谢分析显示,高BMI组和低BMI组患者手术前,术后1个月、3个月、6个月及12个月TC、TG、LDL-C、HDL-C的变化趋势比较,差异均无统计学意义(P>0.05);糖代谢分析显示,高BMI组和低BMI组患者手术前,术后1个月、3个月、6个月及12个月HbA1c、FC-P的变化趋势比较,差异均无统计学意义(P>0.05);高BMI组患者FPG水平术后3个月[(5.7±1.4) vs (7.0±1.8)]、6个月[(5.5±1.6) vs (6.7±2.1)]及12个月[(5.4±1.2) vs (6.7±1.6)]明显低于低BMI组,两组比较差异均有统计学意义(P<0.05);高BMI组患者2 hPG水平术后1个月[(9.3±1.5) vs (10.8±1.7)]、3个月[(9.0±1.8) vs (10.2±1.4)]及6个月[(7.9±1.3) vs (8.7±1.1)]明显低于低BMI组,两组比较差异均有统计学意义(P<0.05);高BMI组患者术后疗效为93.2%,与低BMI组的88.5%比较差异无统计学意义(P>0.05)。单因素分析结果显示,术后1年缓解的相关影响因素为FPG、糖尿病病程及术前用药情况(P<0.05)。结论 Roux-en-Y胃旁路术对BMI≥30.0 kg/m2或BMI<30.0 kg/m2的2型糖尿病患者均具有良好的疗效和安全性。术前空腹血糖水平低、病程短的2型糖尿病患者术后1年手术缓解率较好。