OBJECTIVEThis research aimed to investigate the expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) in mandibular distraction osteogenesis (DO) regulated by parathyroid hormone (PTH) and to explore the mechanism by which PTH promotes DO.

METHODSA rabbit mandibular DO model was established. The rabbits were randomly divided into experimental group and control group. The former were subcutaneously injected with different doses of PTH on alternate days, the latter was injected with normal saline every other day. Serum OPG levels were detected through enzyme-linked immunosorbent assay. The OPG and RANKL expression levels in the DO-induced formation of a new bone tissue were examined through immunohistochemistry staining.

RESULTSThe serum OPG levels gradually increased during distraction. At the end of the stretch, the OPG expression in the experimental group was significantly stronger than that in the control group. As the fixed period was extended, the OPG expression in the new bone gradually decreased, but the RANKL expression increased.

CONCLUSIONIntermittent subcutaneous PTH injection can upregulate the OPG expression and accelerate bone metabolism. Thus, this procedure promotes the early generation of a new bone in the mandible through DO.

Animals ; Enzyme-Linked Immunosorbent Assay ; Mandible ; NF-kappa B ; metabolism ; Osteogenesis, Distraction ; methods ; Osteoprotegerin ; metabolism ; Parathyroid Hormone ; metabolism ; RANK Ligand ; metabolism ; RNA, Messenger ; Rabbits ; Random Allocation

OBJECTIVEThe purpose of this study was to study the changes in the inferior alveolar vessels and angiogenesis following mandibular lengthening with different rates of distraction.

METHODSBilateral mandibular corticotomies were performed in 6 goats. The mandibles in 6 goats were lengthened 10.0 mm using a custom-made distractor with different rates of distraction (1.0 mm/d[n = 3] and 2.0 mm/d [n = 3]); the other 2 nondistracted mandibles served as control. The goats with distracted mandibles were killed at 2 weeks after completion of distraction. The inferior alveolar vessels with distracted calluses were harvested and processed for histologic and morphometric evaluation.

RESULTSNo pathological changes in the inferior alveolar vessels were found following mandibular osteodistraction. However, the number of microvessels within distraction gap in the animals distracted at a rate of 1.0 mm/day was greater than that in the goats distracted using a rate of 2.0 mm/day, and more mature newly formed bone trabeculae was observed.

CONCLUSIONThere were no significant changes in the inferior alveolar vessels after mandibular lengthening with distraction osteogenesis, but rapid distraction may have adverse effects on the aniogenesis in the distraction gap.

Alveolar Process ; blood supply ; Animals ; Blood Vessels ; physiology ; Capillaries ; physiology ; Goats ; Male ; Mandible ; blood supply ; surgery ; Neovascularization, Physiologic ; Osteogenesis, Distraction ; Osteotomy

Objective To analyze the clinical features, diagnosis, treatment and prognosis of neurosyphilis. Methods Clinical data on and laboratory findings in 18 cases with neurosyphilis collected in the Affiliated Provincial Hospital, Anhui Medical University from 2006 to 2008 were retrospectively studied.Results Among the 18 patients, 3 sufferred from asymptomatic neurosyphilis, 1 from meningeal syphilis, 7 from meningovascular syphilis, 5 from paralytic dementia, and 2 from intracranial space-occupation. Toluidine red unheated serum reagin test (TRUST) and Treponema pallidum particle agglutination test (TPPA) of sera were positive in all the patients; cerebrospinal fluid (CSF) TRUST was positive in 16 patients, and CSF TPPA in all patients. An increase was observed in CSF leukocyte count in 7 patients and in CSF protein in 13 patients.The findings on cerebral magnetic resonance imaging (MRI) mainly included demyelination, brain atrophy,cerebral infarction, etc. All the patients, except 2 with a TRUST titer of 1:4, experienced a 4-fold decrease in TRUST titer within a 3-month follow up. Clinical symptoms of neurosyphilis improved in all patients except 1 with paralytic dementia. Conclusions The diversity of clinical manifestations usually leads to the misdiagnosis of neurosyphilis, which should be diagnosed based on comprehensive analysis of clinical characteristics as well as laboratory and imaging findings. Early diagnosis and treatment are beneficial to its prognosis.

Parathyroid hormone(PTH) is synthesized and secreted by chief cell of Gley's glands which possesses dual functions of catabolism and anabolism.It regulates the proliferation and differentiation of multiple cell lines including osteoblast,osteoclast and skeletal lining cells.Furthermore,PTH activates various signaling pathways which control calcium,phosphorous' metabolism and bone conversion,accelerating the bone regeneration and reconstruction.However,the study of PTH in craniomaxillofacial bone regeneration is relatively less and whether the role of parathyroid glands and the mechanism of ossification are consistent with the long bone or not needs further investigation.This review focuses on the progress of PTH in craniomaxillofacial bone regeneration in recent years.

OBJECTIVETo study the biomechanical properties of the new bone generated by mandibular distraction osteogenesis (DO).

METHODSA total of 11 healthy adult goats were randomly divided into 2 groups, the experimental group (n=9) and the control group (n=2). For the goats in the experimental group, the bilateral mandibles were gradually lengthened for 10 mm with distraction appliances. Three goats were sacrificed respectively at 2, 4 and 8 weeks after completion of distraction. Compressive, three-point bending and shearing tests were conducted on the standard regenerated bone samples and the whole unilateral mandibular specimens. For the goats in the cont rol group, no operation was made and the whole unilateral mandible was taken as the test specimen.

RESULTSThe compressive strength and bending stiffness of the new bone reached the normal level at 4 and 8 weeks after completion of distraction, respectively. But the shearing strength remained significantly weaker than that of the controls at 8 weeks after distraction.

CONCLUSIONSThe distraction appliance can be removed and the lengthened mandible should be exposed to adaptive functional exercise at 8 weeks after completion of distraction.

Animals ; Biomechanical Phenomena ; Bone Regeneration ; physiology ; Goats ; Male ; Mandibular Advancement ; Models, Animal ; Osteogenesis, Distraction ; Probability ; Random Allocation ; Reference Values ; Tensile Strength

Objective To understand the current status of receiving no methadone maintenance treatment (MMT) and influencing factors in HIV infected injecting drug users (IDUs) in Dehong Dai and Jingpo autonomous prefectures,Yunnan province.Methods Data of survival of IDUs with AIDS in Dehong were collected from "Chinese National Comprehensive HIV/AIDS and Care Information System" in December,2014.Results There were 987 IDUs who should receive MMT,the majority of them were males (94.6％,934/987),aged 35-44 years (53.0％,523/987) and farmers (77.2％,762/987).Among the 987 IDUs,60.2％ (592/987) received no MMT.Multivariate logistic regression analysis showed that being female (OR=2.66,95％CI:1.21-5.87),in Jingpo ethnic group (OR=3.05,95％CI:1.97-4.71) were the major risk factors for receiving no MMT;not being farmers (OR=0.46,95％CI:0.31-0.70),in Dai ethnic group (OR=0.53,95％CI:0.36-0.79),diagnosed HIV infection history ≥ 10 years (OR=0.60,95％CI:0.45-0.81) were the major protective factors for receiving no MMT.The reasons for receiving no MMT included long distance journey (289,48.8％),fear of exposure (124,20.9％),poor daily medication compliance (59,10.0％),fear of side effects (47,7.9％),others (73,12.3％).Conclusions The proportion of receiving no MMT in IDUs with AIDS in Dehong was high.Being female and farmer,in Jingpo ethnic group,low educational level,short diagnosed HIV infection history were influencing factors for receiving no MMT.The effective intervention measures should be taken to further improve MMT coverage according to the different characteristics of the patients.

BACKGROUND:Bone defects are caused by many factors,such as inflammation,tumor,trauma or bone diseases.Erythropoietin can promote the differentiation of mesenchymal stem cells into osteoblasts and osteoclasts and act on vascular endothelial cells to induce angiogenesis and accelerate the repair of bone and cartilage defects.Erythropoietin is a growth factor with potential application in bone tissue engineering construction. OBJECTIVE:To expound the application and potential mechanism of erythropoietin in bone tissue engineering. METHODS:The first author searched the related articles published in CNKI,WanFang,VIP,and PubMed databases from 2004 to 2022 by computer.Search terms were"erythropoietin,bone defect,bone regeneration,angiogenesis,osteogenesis,osteoblast,osteoclast,bone tissue engineering"in Chinese and English.Finally,64 articles were included for review. RESULTS AND CONCLUSION:(1)Erythropoietin can directly act on osteoblasts and osteoclasts in the bone marrow microenvironment by promoting the differentiation of mesenchymal stem cells into osteoblasts,osteoclasts,adipocytes,nerve cells and stromal cells.The activation of Wnt/β-catenin,hypoxia-inducible factor 1α/vascular endothelial growth factor,p38 MAPK and EphrinB2/EphB4 signaling pathways mediates the osteogenic differentiation of mesenchymal stem cells.(2)Erythropoietin can not only regulate the production of erythrocytes to alter the oxygen-carrying capacity of blood but also stimulate vascular endothelial cells to promote angiogenesis.The new blood vessels can carry oxygen,nutrients,growth factors,and bone progenitor cells necessary for osteogenesis to the osteogenic site,thereby promoting bone formation and fracture healing.(3)Currently,erythropoietin is being used as a growth factor with osteogenic and angiogenic effects in various types of scaffold materials such as chitosan,polycaprolactone,bioceramics,and nanofibers through various drug delivery methods.Erythropoietin,along with other growth factors such as bone morphogenetic protein-2 and bone morphogenetic protein-9,has been applied to the surface of scaffold materials to participate in the repair of bone defects.Erythropoietin has demonstrated excellent practicality in the construction of new tissue-engineered bone and has potential clinical application value.

Objective: To investigate the effect of parathyroid hormone (PTH) on the bone healing of mandibular ramus osteotomy. Methods: The mandibular ramus osteotomy model was established in sixty rabbits and these rabbits were randomly divided into experimental group A, experimental group B and control group. In the experimental group A and experimental group B, the rabbits were given PTH (20 and 40 μg/kg respectively) every other day after operation. In the control group, 1 ml saline was given. The animals were sacrificed at 1 week, 2 weeks, 3 weeks and 4 weeks postoperatively. The new bone formation was observed by histology and cone bone CT. The expression of osteoprotegerin and receptor activator of nuclear factor kappa-B (RANKL) in the new bone was detected by real-time quantitative PCR. Results: The experimental groups has better osteogenesis and the bone mineral density than the control group in osteotomy area. The experimental group B showed the best osteogenesis.Osteoprotegerin mRNA expression in experimental group A (1.127±0.035, 1.742±0.049, 1.049±0.062, 1.063±0.036) was significantly higher than that in the control group in each period (0.965±0.082, 1.254±0.071, 0.793±0.061, 0.684±0.055) (P=0.010, P=0.000, P=0.001, P=0.020), while group B (1.416±0.205, 2.648±0.168, 1.652±0.091, 1.712±0.070) was significantly higher than group A (P=0.000, P=0.010, P=0.023, P=0.003). RANKL mRNA expression in control group (1.666±0.086, 1.058±0.105, 0.885±0.124, 0.972±0.136) was significantly higher than that of the group A (0.788±0.036, 0.585±0.017, 0.692±0.017, 0.527±0.051) (P=0.001, P=0.006, P=0.003, P=0.028) in each period, while group A was significantly higher than group B(0.247±0.022, 0.240±0.034, 0.134±0.011, 0.103±0.050) (P=0.000, P=0.001, P=0.002, P=0.012). Conclusions PTH can upregulate the expression of osteoprotegerin and reduce expression of RANKL, thus promoting new bone formation. Intermittent administration of high dose of parathyroid hormone can further promote the healing process after mandibular ramus osteotomy.