长航海勤人员骨密度状况调查及影响因素分析*

目的:研究长航海勤人员骨密度情况及影响因素,为开展针对性干预提供理论依据。方法:采用双能X线法检测2018-05至2018-09来我院疗养的199名长航海勤人员,其中水面舰艇艇员77人、潜艇艇员122人(核潜艇69人)的骨密度(BMD)值,并分析年龄、体质指数、长期饮用(≥6个月)碳酸/含糖饮料对骨密度的影响。结果:长航海勤人员骨密度(BMD) 值平均为 0.5544±0.0599,骨质疏松3例(1.5%),骨量减少58例(29.2%);30 ～39岁年龄段的BMD明显高于<30岁年龄段(P＜0.05);潜艇官兵的BMD值显著高于水面舰艇组(P＜0.01);长期饮用碳酸/含糖饮料者的BMD值高于不饮用者(P＜0.05)。结论:长航作业环境及不良生活方式可导致长远航海勤人员骨密度降低;做好针对性干预,对维护海勤官兵骨骼健康具有重要意义。     

纳米珍珠粉/壳聚糖-透明质酸支架修复兔股骨远端骨缺损的实验研究

通过体内实验探讨纳米珍珠粉/壳聚糖-透明质酸(NPP/C-HA)复合支架的促成骨能力。采用双侧兔股骨远端骨缺损模型(直径7 mm,深度10 mm),通过大体标本、影像学检查、分子生物学检查及组织学检查来观察骨缺损的修复效果。发现各组均未出现明显不良组织反应;随观察时间增加实验组骨缺损区范围最小,在第8周和第12周数据的差异存在统计学意义(P<0.05);在第4周、6周、8周时实验组BALP含量与其他组比较P<0.05;实验组缺损区边缘出现更多的新生骨,但在骨质成熟度上未见明显差异。结果表明NPP/C-HA支架具有良好的生物相容性及促成骨作用,为进一步研究NPP/C-HA在骨组织工程中的作用提供了实验和理论基础。     

The first evidence of an infectious disease in early penguins

Traces of skeletal response to trauma are poorly documented for early (i.e. Paleogene, 66–23 Ma) penguins (Sphenisciformes) and infectious diseases that afflicted these seabirds have not been previously put on record. We report osteomyelitis (OM), typically a bacterial infection of bone, in a proximal pedal phalanx of a ‘giant’ penguin from the Eocene (56–34 Ma) of West Antarctica. Osteomyelitis had apparently complicated healing of a fracture. The injury left an oblique scar within the proximal aspect of the plantar surface, resulting in deformation of the articular surface. The recognised evidence of OM includes characteristic periosteal reaction as well as focal bone-loss and necrosis.     

Response of the tooth-periodontal ligament-bone complex to load: A microCT study of the minipig molar

One strategy evolved by teeth to avoid irreversible damage is to move and deform under the loads incurred during mastication. A key component in this regard is the periodontal ligament (PDL). The role of the bone underlying the PDL is less well defined. We study the interplay between the PDL and the underlying alveolar bone when loaded in the minipig. Using an Instron loading device we confirmed that the force-displacement curves of the molars and premolars of relatively fresh minipig intact mandibles are similar to those obtained for humans and other animals. We then used this information to obtain 3D images of the teeth before and after loading the tooth in a microCT such that the load applied is in the third linear part of the force displacement curve. We observed that at many locations there is a complimentary topography of the cementum and alveolar bone surface, strongly suggesting an active interplay between the tooth and the bone during mastication. We also observed that the loaded tooth does not come into direct contact with the underlying bone surface. A highly compressed layer of PDL is present between the tooth and the bone. The structure of the bone in the upper furcation region has a unique appearance with little obvious microstructure, abundant pores that have a large size range and at many locations the bone at the PDL interface has a needle-like shape. We conclude that there is a close interaction between the tooth, the PDL and the underlying alveolar bone during mastication. The highly compressed PDL layer that separates the tooth from the bone may fulfill a key shock absorbing function.     

A peptide from Testudo horsfieldii tortoise spleen as a potential helper for reducing acute radiation syndrome

The Middle Asian tortoise Testudo horsfieldii is one of the most radioresistant animals, with Lethal Dose (LD) 50/30 around 500 Gy. Extracts were prepared from different organs of the tortoise, and their biological activity was evaluated. Crude extract from the spleen was found to significantly increase survival of mice treated with lethal doses of radiation. In an iterative process, the active extract was purified by chromatography, and the fractions were screened for biological activity. Various vital parameters were monitored: peripheral blood leukocytes, spleen colonies, mitosis in the bone marrow, and survival after 30 days. The process concluded with the isolation, characterization, and synthesis of the tetrapeptide FTGN, which accelerated repopulation of the irradiated bone marrow at very low concentrations both in vivo and ex vivo. A fluorescently labeled derivative of the peptide was found to selectively associate to CD34⁺ stem cells, suggesting that the peptide mediates their proliferation and allows fast repopulation of hematopoietic lineages. Interestingly, the peptide protected animals from alopecia. The studies in experimental animals suggest that treatment with FTGN can potentially benefit patients who suffer bone marrow damage due to radiotherapy or chemotherapy and patients undergoing autologous or allogenic bone marrow transplantation.     

High-throughput staining for the evaluation of fetal skeletal development in rats and rabbits

Typical developmental toxicity studies require the assessment of fetal skeletal development. Regulatory guidelines require the assessment of bone ossification and indicate preferences for an assessment of both ossified bone as well as cartilaginous elements. Current manual methods to process fetuses for skeletal examination, whether single or double staining, are laborious and time consuming, and ultimately extend the time before study interpretations. There is a definite need for a quick and efficient, yet reliable, procedure to generate stained fetal skeletons for analysis. A non-automated high-throughput method for single and double staining rat and rabbit fetuses for skeletal evaluations is described, which results in excellent quality specimens ready for evaluations in approximately 3 days for rats and 7 days for rabbits.     

Identification of differentially expressed genes in the developing antler of red deer Cervus elaphus

Understanding the molecular mechanisms underlying bone development is a fundamental and fascinating problem in developmental biology, with significant medical implications. Here, we have identified the expression patterns for 36 genes that were characteristic or dominant in the consecutive cell differentiation zones (mesenchyme, precartilage, cartilage) of the tip section of the developing velvet antler of red deer Cervus elaphus. Two major functional groups of these genes clearly outlined: six genes linked to high metabolic demand and other five to tumor biology. Our study demonstrates the advantages of the antler as a source of mesenchymal markers, for distinguishing precartilage and cartilage by different gene expression patterns and for identifying genes involved in the robust bone development, a striking feature of the growing antler. Putative roles for “antler” genes that encode α-tropomyosine (tpm1), transgelin (tagln), annexin 2 (anxa2), phosphatidylethanolamine-binding protein (pebp) and apolipoprotein D (apoD) in intense but still controlled tissue proliferation are discussed.     

Neural crest cell deficiency of c-myc causes skull and hearing defects

The proto-oncogene c-myc has a central role in multiple processes important for embryonic development, including cell proliferation, growth, apoptosis, and differentiation. We have investigated the role of c-myc in neural crest by using Wnt1-Cre-mediated deletion of a conditional mutation of the c-myc gene. c-myc deficiency in neural crest resulted in viable adult mice that have defects in coat color, skull frontal bone, and middle ear ossicle development. Physiological hearing studies demonstrated a significant hearing deficit in the mutant mice. In this report, we focus on the craniofacial and hearing defects. To further examine neural crest cells affected by c-myc deficiency, we fate mapped Wnt1-Cre expressing neural crest cells using the ROSA26 Cre reporter transgene. The phenotype obtained demonstrates the critical role that c-myc has in neural crest during craniofacial development as well as in providing a model for examining human congenital skull defects and deafness.     

Deep-freeze preservation of cranial bones for future cranioplasty: nine years of experience in Soroka University Medical Center

Background Decompressive craniectomy is routinely performed in many neurosurgical centers to treat intracranial hypertension refractory to medical therapy as a result of head trauma, CVA or various brain tumors. When the patient survives his illness, cranioplasty with autologous bone graft or other reconstructive materials is considered to repair the skull defect. Objective This prospective study reviews the cases of decompressive craniectomies followed by later cranioplasty undertaken at our institute through the years 1996 and 2005 and describes the method used for preservation of removed bone flaps for future cranioplasty. Subjects and methods Sixty-eight patients underwent decompressive craniectomies since 1996. A protocol was designed to prepare the removed bone flaps for deep freeze preservation. After removal, the bone flaps were transferred to the skin bank at our institution within 6 h, gently rinsed using 1–3 liters of sterile saline (0.9% NaCl) supplemented with antibiotics (neomycin, 2 mM) with no dimethylsulfoxide (DMSO), then flaps were wrapped in two layers of sterile plastic coverage and preserved at −80°C. Results The patient’s population will be presented. Since 1996 we have performed 12 cranioplasties using deep-freeze preserved autologous bone graft. It took a rather long learning period, beginning with a single patient per year and continued with several others. Up to now, no case of infection, osteomyelitis or bone resorption following cranioplasty have occurred. Conclusion Deep-freeze preservation of autologous bone grafts to reconstruct skull defects after decompressive craniectomy is a useful procedure and has a low revision rate. N. Grossman: deceased 23 December 2006.