Comparison of two silica-based extraction methods for DNA isolation from bones

One of the most demanding DNA extractions is from bones and teeth due to the robustness of the material and the relatively low DNA content. The greatest challenge is due to the manifold nature of the material, which is defined by various factors, including age, storage, environmental conditions, and contamination with inhibitors. However, most published protocols do not distinguish between different types or qualities of bone material, but are described as being generally applicable. Our laboratory works with two different extraction methods based on silica membranes or the use of silica beads. We compared the amplification success of the two methods from bone samples with different qualities and in the presence of inhibitors. We found that the DNA extraction using the silica membrane method results an in higher DNA yield but also in a higher risk of co-extracting impurities, which can act as inhibitors. In contrast the silica beads method shows decreased co-extraction of inhibitors but also less DNA yield. Related to our own experiences it has to be considered that each bone material should be reviewed independently regarding the analysis and extraction method. Therefore, the most ambitious task is determining the quality of the bone material, which requires substantial experience.     

Clinical picture of diabetic osteoarthropathy

Summary On the basis of data from the pertinent literature and of a thorough examination of 23 cases observed by himself the author illustrates findings concerning the occurrence, clinical picture and interrelations of clinical and radiological symptoms in diabetic osteoarthropathy. These alterations occur most frequently in middleaged or elderly diabetic patients with unstable metabolism or poor control, usually after a long duration of diabetes. Clinical symptoms are divided into 4 groups. Neurological symptoms (group I) are detectable at every stage of the process. Sometimes bone destruction is concomitant but neurological changes are the sole symptoms. Loose joints and articular swelling (group II) are frequently premonitory signs of bone alterations. Plantar ulcers (group III) are often associated with bone changes. Detectable foot deformities (group IV) are mostly an indication of the end stage of the process.     

石膏固定和空心螺钉内固定修复腕部舟状骨新鲜骨折:功能恢复比较

背景：由于舟状骨在腕部的特殊位置骨折难以获得稳妥的固定,加之其特殊的解剖及血液供应特点容易导致骨折不愈合甚至骨缺血性坏死。在腕部舟状骨新鲜骨折石膏固定和内固定治疗方法上依然存在不同的争议。目的：比较分析石膏固定和空心螺钉内固定修复腕部舟状骨新鲜骨折的功能恢复情况。
　　方法：纳入新疆医科大学第一附属医院2012年3月至2014年3月收治的腕部舟状骨新鲜骨折22例,患者均为新鲜舟状骨腰部骨折,受伤时间2 h-12 d。患者术前X射线拍片示：未见腕部舟状骨塌陷、月骨周围脱位、缺血性骨坏死及骨性改变等表现。所有病例均为有移位、不稳定性骨折。根据患者意愿及手术方法选择等分为石膏组和空心螺钉组进行疗效对比分析,每组11例。随访时对两组患者进行Cooney腕关节功能评分。两组患者年龄分布、性别差异无显著性意义(P >0.05)。
　　结果与结论：随访3-6个月对比分析石膏组和空心螺钉组患者腕关节功能Cooney评分,空心螺钉组优9例,良1例,可1例,差0例;石膏组优1例,良5例,可3例,差2例,空心螺钉组患者治疗后优良率为91%,石膏组患者治疗后优良率为55%,空心螺钉组显著高于石膏组(t=4.817,P <0.05)。提示虽然石膏固定在腕部舟状骨新鲜骨折上具有一定的疗效,但在修复后腕关节功能恢复方面,切开复位空心螺钉内固定疗效显著并且患者腕关节功能恢复较快。因此与石膏固定相比,切开复位空心螺钉内固定修复腕部新鲜舟状骨骨折更具优势。     

骨血管源性恶性肿瘤的临床分析

目的 回顾性分析临床上少见的血管源性恶性骨肿瘤的诊断、治疗和临床疗效.方法 从1998年10月至2008年11月我科诊治7例骨血管源性恶性肿瘤患者,包括5例血管内皮瘤和2例血管肉瘤.男4例,女3例;年龄19～76岁,平均42.6岁.1例为多中心病变,6例为单中心.1例病变位于椎体,其余6例位于四肢骨.所有患者均以局部疼痛就诊,病变影像学表现均为溶骨性破坏.其中2例血管肉瘤伴有软组织包块.1例脊柱病变接受边缘切除和术后放疗,5例接受广泛切除重建或截肢术,未行放化疗,另外1例放弃治疗.所有患者均经病理学诊断确诊,平均随访40个月(1～89个月).结果 股骨上段血管肉瘤患者半盆截肢后于术后17个月死于肺和内脏多发转移.脊柱血管内皮瘤患者术后3年死于其他原因.胫骨上端血管内皮瘤患者术后6年出现局部软组织复发,予以再次完整切除.保守治疗的患者带瘤生存,其他3例患者均无瘤生存.结论 骨的血管源性恶性肿瘤临床少见,主要根据病理学检查确诊,同一解剖部位的多中心病灶对诊断有一定特异性.手术广泛切除为治疗四肢病变的主要手段,椎体病变瘤内刮除后可辅以术后放疗.血管肉瘤恶性程度高、预后差.     

Comments on the Hypotheses Underlying Fracture Risk Assessment in Osteoporosis as Proposed by the World Health Organization

It was shown in a recent multivariate analysis of lumbar vertebral (L1–L3) CT scans of 171 women without fractures and 57 fractures somewhere in their skeletons, that regional assessment of the spinal mineral distribution can result in the discrimination of the above patient groups with an accuracy of about 90%. This level of discrimination was possible even in those cases with bone densities below the fracture threshold, where the overlap of patients with and without fractures is the greatest and clinically the most significant. In this region this new analytical technique could also identify a subgroup of patients who not yet had a fracture, but for whom all three lumbar vertebrae were classified as osteoporotic. From these results it follows that the osteoporosis model proposed by the World Health Organization (WHO), which assumes that fragility depends only on a single mean value of bone mineral density (BMD) for a patient, is overly simplistic and requires upgrading to include indices representing the distribution of bone mineral. Received: 25 November 1997 / Accepted: 24 June 1998     

Accuracy of microCT in the quantitative determination of the degree and distribution of mineralization in developing bone

Purpose: To evaluate the accuracy and applicability of a commercially available microCT system for comparative measurements of the degree and distribution of mineralization of developing bone. Material and Methods: Homogeneous K₂HPO₄ solutions with different concentrations (range 0-800 mg/cm³) were used to assess the accuracy of a microCT system equipped with a polychromatic X-ray source. Both high (45 kV) and low (70 kV) tube peak voltages were explored. The resulting attenuation was compared with calculated theoretical attenuation values to estimate the accuracy. As an example of its applicability, the method was used to assess changes in the degree of mineralization of various regions of the mandible from two pigs of different developmental age. Results: On average, the estimated error of the measured linear attenuation was 10% or less. Accuracy was dependent on the average mineral concentration, the size of the sample, and the energy of the X-ray beam. The accuracy of the microCT system appeared sufficient to distinguish regional differences in the degree of mineralization within and between specimens of developing mandibular bone. Furthermore, the resolution of the system allowed identification of different degrees of mineralization within trabeculae. Conclusion: Accuracy of microCT with polychromatic radiation can be considered adequate for assessment of the degree of mineralization of developing bone. Therefore, this method provides a three-dimensional means by which to simultaneously investigate the bone structure as well as the degree of mineralization during development in a non-destructive manner and with high resolution.     

Bone structure of the calcaneus: analysis with magnetic resonance imaging and correlation with histomorphometric study

The purpose of this study was to compare structural measurements obtained from MR images of the calcaneus with those obtained from conventional histomorphometry. Sagittal magnetic resonance (MR) images of the calcaneus of 24 fresh human cadaveric feet were obtained at a spatial resolution achievable in vivo. A three-dimensional gradient echo-sequence was used with a slice thickness of 700 m and in plane resolution of 172×172 m. Structural analysis (four histomorphometric parameters; seven connectivity parameters) was performed in the superior region of the calcaneus. Bone biopsy specimens were obtained in the same area and were sectioned for histomorphometric study. Most of the MR histomorphometric parameters were overestimated (by a factor ranging from 0.8 to 3), as compared with histomorphometry. However, significant (P<0.05) correlations were found between MR imaging and histomorphometric measurements for bone volume/tissue volume, trabecular separation, trabecular number, star volume of the marrow space, node count and terminus count. MR histomorphometric parameters correlated much better with histomorphometry than connectivity parameters. This study suggests that structural parameters characterizing cancellous bone in the calcaneus can be derived from MR images in the limited spatial resolution regime applicable in vivo.     

Radiographic evaluation and unusual bone formations in different genetic patterns in synpolydactyly

Objective To compare the radiological findings of heterozygous and homozygous subjects with synpolydactyly (SPD) and to discuss their unusual bone formations.Design and patients Families with hand and foot SPD were examined. Genetic analysis was performed with blood samples and the pedigree was constructed. The affected individuals, especially those with distinctive phenotypic features, were invited to our orthopaedics clinic for further diagnostic studies. All participants underwent detailed clinical and X-ray examinations.Results Of the invited patients, 16 (five female and 11 male; age range 4–37 years, mean age 10.75 years) were included in our study, and hand and foot radiographs were obtained. All subjects had bilateral hand radiographs (32 hands), and 14 had bilateral foot radiographs (28 feet). Genetic analysis revealed 12 heterozygote (75%) and four (25%) homozygote phenotypes. Among patients enrolled into the study nine (three homozygotes, six heterozygotes) had SPD of both hands and feet bilaterally (tetrasynpolydactyly). Six unusual bone formations were observed in the hands and feet: delta phalanx, delta metacarpal/metatarsal, kissing delta phalanx, true double epiphysis, pseudoepiphysis and cone-shaped epiphysis. There were major differences in radiological and clinical manifestations of homozygote and heterozygote phenotypes. The homozygous SPD presented with very distinctive unusual bone formations.Conclusion The existence and variety of unusual bones may indicate the severity of penetrance and expressivity of SPD.This paper was presented as an EPOS at the 11th Annual Meeting of the ESSR 2004 in Augsburg, Germany     

MR imaging of avascular scaphoid nonunion before and after vascularized bone grafting

Objective To investigate the magnetic resonance (MR) imaging appearances of chronic nonunion of the scaphoid with proximal pole avascular necrosis before and after insertion of a vascularized bone graft, using computed tomography (CT) as the imaging gold standard.Design and patients A retrospective study was performed involving MR imaging (n=26), CT scans (n=37) and radiographs (n=52) of 13 men (mean age 29 years, age range 20–38 years) with avascular scaphoid nonunion. Avascular necrosis of the scaphoid proximal pole was confirmed intraoperatively (n=13). MR images were acquired preoperatively and following placement of a vascularized bone graft. Scaphoid MR signal characteristics were assessed for evidence of vascular bone graft incorporation and revascularization of the bone marrow of the proximal pole of the scaphoid and compared with the gold standard of CT. Surgical and clinical notes were reviewed with a minimum 3 year imaging and clinical follow-up in all patients.Results Graft incorporation with revascularization of the proximal pole of the scaphoid was documented in 9 patients (69%). Graft failure with persistent pseudoarthrosis and avascular necrosis of the scaphoid was seen in 4 patients (31%).Conclusions MR imaging is useful to determine whether vascularized bone graft incorporation and revascularization of the proximal pole of the scaphoid has occurred in the setting of avascular scaphoid nonunion.Paper presented at ESSR, European Society of Skeletal Radiology, Aarhus, Denmark, 14 June 2003. Awarded first prize for the ESSR award for Scientific PresentationsPaper presented at ISS, Closed Scientific Session, Malta, 3 October 2004 as part of the above prize     

A clinical and therapeutic approach to thyrotoxicosis with thyroid-stimulating hormone suppression only

Subclinical hyperthyroidism is defined as normal serum free thyroxine (T4) and triiodothyronine (T3) concentrations and persistently suppressed thyroid stimulating hormone (TSH) concentrations. The most common cause of subclinical hyperthyroidism is the use of suppressive doses of L-thyroxine for treatment of hypothyroidism or, less commonly, diffuse nontoxic goiter or thyroid carcinoma (exogenous subclinical hyperthyroidism). Endogenous subclinical hyperthyroidism may be caused by a variety of thyroid disorders that result in overproduction and release of thyroid hormones from the gland with normal/high 24-hour thyroid radioiodine uptake or by inflammation in the thyroid resulting in release of excess thyroid hormones and low 24-hour thyroid radioiodine uptake. Several groups have investigated whether persistent endogenous or exogenous subclinical hyperthyroidism, like overt hyperthyroidism, causes symptoms, adverse effects on the cardiovascular and the skeletal systems, and increased mortality, whether endogenous subclinical hyperthyroidism evolves to overt thyrotoxicosis, and whether or not it should be treated. The present report reviews the most important and recent studies of subclinical hyperthyroidism and attempts to draw conclusions based upon the literature and the authors' experience.