Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Osteogenesis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed1993

An experimental study of chondrogenesis and osteogenesis in rat submandibular gland induced by implantation of demineralized dentin.

Demineralized dentin pieces were implanted in 18 rat submandibular glands to examine the chondrogenesis and osteogenesis in pleomorphic adenoma of the salivary gland. After 7 days of implantation, a large amount of cartilage tissue was found next to the inner portions of the implanted pieces, and small amounts of the osteoid and cartilage tissues were detected next to the outer portions. A small amount of bone tissue was found in contact with the cartilage 10 days after the implantation. In the inner portions, invasions of capillaries and a small amount of osteoid tissue were noted. These histological findings resembled those of endochondral ossification. Large amounts of bone tissue and resorption of the implant were observed after 14 days. It has been suggested that cartilage and bone are produced by bone morphogenetic proteins (BMP) in demineralized dentin resulting in chondrogenesis followed by osteogenesis in submandibular gland. Apparently, undifferentiated mesenchymal cells are produced by implantation, undergo dedifferentiation, and are redifferentiated into chondroblasts and osteoblasts in the presence of BMP. These results suggest that chondrogenesis and osteogenesis in the submandibular gland are induced by BMP. It is possible that the chondroid tissues in pleomorphic adenoma of the salivary glands are induced by proteins such as BMP.

Adenoma, Pleomorphic↗
PubMed1996

Prenatal diagnosis of osteogenesis imperfecta congenita by ultrasonography.

As well as being a rare connective tissue disorder, osteogenesis imperfecta congenita (OIC) is also the most severe form of osteogenesis imperfecta (OI). We report a case that was diagnosed by sonography in a fetus at 22 weeks of gestation. The diagnosis was confirmed by postnatal radiography and autopsy. The prenatal sonographic findings were: short bowed femurs with fractures and thin skull with unusual clarity of intracranial structures. The postnatal radiography showed crumbled long bones and beaded ribs compatible with multiple fractures, similar to the prenatal sonographic findings. The major findings on autopsy were deformed skull and ribs and asymmetric deformity of the four extremities. The microscopic findings of the skeleton, including skull, vertebrae, ribs and long bones, revealed normal cartilagenous development but abnormal bone formation. The pathologic features of the skeleton were compatible with osteogenesis imperfecta type II, ie, OIC. Fractures and bone deformities are the cardinal symptoms of OIC which make intrauterine diagnosis possible. It should be differentiated from other types of OI (I, III and IV), as their prognoses are different. As OIC is lethal, the option of pregnancy termination should be offered at the time it is diagnosed. In the present report, termination by extraovular induction was performed immediately after OIC was noted on sonography.

Abortion, Induced↗
PubMed1996

[Left ventricular rupture following aortic and mitral valve replacement in a patient with osteogenesis imperfecta: a case report].

Intraoperative left ventricular rupture (type I) occurred following aortic and mitral valve replacement in 62-year-old man with osteogenesis imperfecta. Re-replacement of the mitral valve and the repair of left ventricular rupture were successfully performed. However, the patient died suddenly 3 days after the operation. Retroperitoneal bleeding due to the insertion of a continuous hemofiltration catheter via the femoral vein was detected at autopsy. Seven patients who underwent double valve replacements for aortic and mitral disease with osteogenesis imperfecta were reported with poor surgical results. We report our patient and discuss the relationship between osteogenesis imperfecta and left ventricular rupture.

Aortic Valve↗
PubMedDate not supplied

Osteogenesis by pulsing electromagnetic fields (PEMFs): optimum stimulation setting.

The optimum setting for electromagnetic stimulation was examined by histologically assessing the degree of osteogenesis at different settings of electromagnetic stimulation, and comparing alkaline phosphatase (ALP) activity in the bone marrow. For this experiment, an electromagnetic field generator manufactured by the Institute of Physical and Chemical Research was used. The intensity of the magnetic field was set at eight levels; 0.1, 0.2, 0.4, 1, 2, 4, 6 and 8 gauss (G). The frequencies used were 5, 10, 20, 50, 100 and 200 Hz. Pulse durations were 6, 12, 25, 50 and 100 micro sec. Significant ALP elevation and osteogenesis were observed at magnetic field intensities of 0.4, 1, and 2G. ALP activity did not differ between different frequencies. ALP activity at pulse durations of 25 and 50 micro sec were significantly higher than at the other pulse durations. The effect of electromagnetic stimulation on osteogenesis greatly depends on the intensity and pulse duration of the stimulation.

Alkaline Phosphatase↗
PubMed1997

Clinical signs and diagnosis of osteogenesis imperfecta in three dogs.

When a young dog is evaluated for multiple fractures with minimal to no accompanying trauma, the primary differential diagnoses are metabolic disease, physical abuse, and osteogenesis imperfecta (OI). Of these, secondary hyperparathyroidism is most common, but if serum concentrations of ionized calcium, phosphorus, vitamin D, and parathormone are within reference ranges, OI must be considered. Osteogenesis imperfecta is a heritable disease characterized by brittle bones. Results of studies using cultured skin fibroblasts indicate that most cases of OI in human beings are caused by a mutation in a type-I collagen gene. Osteogenesis imperfecta was recently identified in 3 dogs. Radiographic findings included multiple fractures in various stages of healing and generalized osteopenia. Cultured fibroblasts from skin biopsy specimens were used to diagnose OI. Structural abnormalities were found in type-I collagen from each dog. This cell culture assay can be used to evaluate dogs with brittle bones.

Animals↗
PubMed1997

The Nicholas Andry Award-1996. The molecular pathology of osteogenesis imperfecta.

A systematic analysis of the molecular pathology of osteogenesis imperfecta was undertaken in 200 cases. The findings indicate that molecular defects of Type I collagen are the major cause of this disease. The mild form of osteogenesis imperfecta is caused by quantitative anomalies of Type I collagen. The other forms of the disease, which are more severe, are caused by quantitative and qualitative anomalies of Type I collagen. The mutant Type I collagen molecules are secreted poorly and are susceptible to intracellular and extracellular degradation with loss of normal and mutant collagen chains. The mutant molecules severely impair the formation of the extracellular matrix causing an abnormal architecture of dermis and bone. The molecular pathology was correlated with the clinical, radiologic, and pathologic features. As a result, the clinical classification was expanded and a new biochemical classification of osteogenesis imperfecta was developed.

3T3 Cells↗
PubMed1998

Blood flow measurement during distraction osteogenesis.

The regional blood flow of 30 distraction segments in 27 patients was measured during distraction osteogenesis. There were three groups of patients. Group A consisted of seven patients with high grade malignant tumors who received chemotherapy preoperatively and postoperatively. Group B consisted of eight patients with low grade malignant and aggressive benign tumors, who all were treated without chemotherapy. Group C (the control group) consisted of 12 patients with nontumoral conditions. Using quantitative technetium scintigraphy, the regional blood flow within the distracted segment and surrounding soft tissues was measured. The measured radioisotope count was expressed as the ratio of the distracted site to the control site (blood flow ratio). The blood flow ratio for all the cases averaged 1.70 +/- 0.70. Group A had a lower blood flow ratio, which was statistically significant in comparison with the other two groups. The external fixation index showed no significant difference in callus formation among these three groups. No correlation was found between the blood flow ratio and external fixation index. Chemotherapy decreases regional blood flow, but with distraction osteogenesis the regional blood flow can be kept within the normal range or higher. Distraction osteogenesis may overcome the effects of chemotherapy by increasing blood flow.

Adolescent↗
PubMedDate not supplied

Bone response to functioning implants in dog mandibular alveolar ridges augmented with distraction osteogenesis.

The specific aim of this study was to determine the response of alveolar bone after it was augmented vertically using distraction osteogenesis and subsequently loaded with implant restorations. Four dogs each had four implants placed horizontally into an edentulous mandibular quadrant and, after integration, a distraction osteogenesis device was fabricated in the laboratory. An osteotomy was made to allow the crest of the alveolar ridge to be distracted vertically. After 10 mm of vertical distraction, the device was stabilized with light cured resin. Following bone fill confirmation of the distraction gap at 10 weeks, two implants were placed into the ridges, one in distracted bone and one in nondistracted bone. After 4 months for implant integration, freestanding prostheses were fabricated. Crestal bone levels were evaluated throughout the period of function. Animals were sacrificed after 1 year of loading, for histologic evaluation of the bone. The vertical ridge augmentation averaged 8.85 +/- 1.05 mm after 10 weeks of healing following distraction, without change over 1 year of implant loading. Histologic examination showed that bone had formed between the distracted segments, creating an augmented ridge. The average thickness of the labial cortex in the distraction gap was significantly thinner than the lingual cortex in distracted bone and the lingual and labial nondistracted cortical bone. The presence of the dental implant did not significantly affect cortical bone thickness. Serial sections showed that implants remained integrated and functional without soft tissue inflammation. Dental implants placed into alveolar ridges augmented with the technique of distraction osteogenesis maintained bone and were functional for the length of this study.

Alveolar Ridge Augmentation↗
PubMed1998

Association of COL1A1 and otosclerosis: evidence for a shared genetic etiology with mild osteogenesis imperfecta.

HYPOTHESIS: Otosclerosis is related to mild osteogenesis imperfecta with genetic defects in type I collagen. BACKGROUND: Otosclerosis is a common bone disease of the human otic capsule that has an underlying hereditary predisposition. The histopathology and clinical manifestations are strikingly similar to the milder forms of osteogenesis imperfecta in which mutations of type I collagen genes have been established as the underlying cause. METHODS: The authors investigated the genetic basis of otosclerosis by conducting an association study using polymorphic DNA markers from patients with clinical otosclerosis and random control subjects. RESULTS: This study showed a significant association between clinical otosclerosis and the type I collagen COL1A1 gene using three different polymorphic markers within the gene. CONCLUSIONS: Some cases of clinical otosclerosis may be related to mutations within the COL1A1 gene that are similar to those found in mild forms of osteogenesis imperfecta and result in null expression of the mutant allele.

Alleles↗
PubMed1997

Distraction osteogenesis for correction of transverse mandibular deficiency: a preliminary report.

PURPOSE: This article reviews the early results with distraction osteogenesis to correct transverse width deficiencies in the mandible. PATIENTS AND METHODS: Nine patients with congenital/developmental maxillofacial skeletal deformities had distraction osteogenesis performed. All patients had study casts and cephalometric and dental radiographs obtained before and after surgery. Eight of the nine patients also had simultaneous surgical assisted-rapid palatal expansion (SA-RPE). The other patient had nonsurgical RPE. RESULTS: Successful completion of the planned mandibular symphyseal distraction was achieved in eight of nine patients. Four of the nine experienced failure of the distraction appliance because of stripping of the distraction tram. Three of them underwent reoperation. The mean expansion achieved in the anterior mandible measured at the canines was 3.9 mm. CONCLUSIONS: These preliminary results suggest that distraction osteogenesis is a viable option to correct transverse discrepancies of the mandible.

Activator Appliances↗
PubMed1994

Distraction osteogenesis in the irradiated canine mandible.

The potential use of distraction osteogenesis in mandibular reconstruction has been limited by its questionable efficacy in previously radiated bone. We studied five mongrel dogs that had a hemimandible rendered edentulous and underwent a full course of external beam radiation therapy (50 Gy/20 fractions). Six months after completion of radiotherapy, a 2-cm critical-size segmental mandibular defect was created and stabilized with a stainless steel plate. A proximal mandibular transport segment was then formed and an external lengthening apparatus (Orthofix) applied. By means of bifocal distraction osteogenesis, the defects were filled with new bone in a period of 30 days in four of five dogs. Histologic analysis and fluorochrome microscopy confirmed the formation of new cortical bone. Our results suggest that distraction osteogenesis is successful in previously radiated bone and that it may be a simple method of mandibular reconstruction following ablative head and neck surgery.

Animals↗
PubMed2003

The use of rapid prototyping in the preoperative planning of distraction osteogenesis of the cranio-maxillofacial skeleton.

OBJECTIVE: In cranio-maxillofacial surgery, the principle of distraction osteogenesis (DO) can be used for the reconstruction of the deformed skull, midface complex, mandible and alveolar ridge. Optimal results can only be obtained with accurate planning of the osteotomies and accurate positioning of the distraction device. In addition, the surgical planning must be transferred very precisely to the patient in the operating theater. The clinical accuracy and utility of stereolithographic models in cranio-maxillofacial distraction osteogenesis of the midface, mandible and alveolar ridge will be demonstrated. MATERIALS AND METHODS: Thirteen patients were treated by DO in the cranio-maxillofacial skeleton. Five patients suffered from midface retrusion and were treated by a LeFort III advancement. One patient suffered from an aseptic necrosis of the condylar process of the mandible and had a reconstruction of the condylar process by DO. Seven patients underwent an osteotomy of the alveolar ridge of the mandible with subsequent placement of distraction screws and implants because of advanced atrophy of the mandible. Following preoperative acquisition and conversion of the CT-scan data, a model was fabricated by stereolithography (SLA). Simulation of the osteotomies and placement of distraction devices was performed on these models, then surgical guides were used to transfer the surgical planning to the patient in the operating theater. Pre- and postoperative facial photographs and X-rays were compared to evaluate the accuracy of the transfer procedure. RESULTS: In all cases, matching of pre- and postoperative facial photographs and X-rays showed reconstruction of the bony structures to be as accurate as planned on the SLA models. Transfer of the surgical plan by means of custom-made surgical guides was optimal in all cases. CONCLUSION: Preoperative planning of distraction osteogenesis of the cranio-maxillofacial skeleton and transfer to the operating theater by custom-made surgical guides remains the standard procedure for the planning of complex distraction cases. However, improvements in surgical simulation software and accurate virtual-reality surgery will probably make the use of these models redundant in the future.

Adolescent↗
PubMed1990

[Ilizarov's distraction osteogenesis using the mono-fixator system and initial clinical experiences with the injured lower leg].

Distraction osteogenesis, as developed by Ilizarov, allows the limbs to be lengthened and intercalary defects to be filled by bone transport without the use of bone grafts. In five patients with traumatic sequelae (fractures of the lower leg), unilateral dynamic mono_fixation and a special distraction apparatus were used for application of the Ilizarov technique. With the distraction device, gradual distraction of the osteotomy surfaces (1/3 mm in three steps per day) is easy for the patients to perform. In three cases distraction osteogenesis was used to correct shortening of the lower leg and in two cases for bridging a tibial defect due to an infection in the plate osteosynthesis. In all cases, the course of treatment and bone healing were uneventful. Based on our first clinical experiences, we believe that mono_fixation provides appropriate stability and the distraction apparatus permits appropriate bone transportation for successful distraction osteogenesis in the tibia.

Adolescent↗
PubMed2007

Callus formation enhanced by BMP-7 ex vivo gene therapy during distraction osteogenesis in rats.

This study was designed to observe the effects of bone morphogenetic protein-7 (BMP-7) ex vivo gene therapy on callus formation during rat mandibular distraction osteogenesis (DO). Fifty-four Sprague-Dawley rats underwent osteodistraction of the right mandible and were then randomly divided into three groups. Immediately after distraction, autologous bone marrow mesenchymal stem cells (MSCs) transfected with BMP-7, MSCs untransfected with BMP-7, and physiological saline were injected into the distraction gaps of the mandibles in groups A, B, and C, respectively. Nine animals from each group were euthanized at 2 and 6 weeks after completion of distraction. The distracted mandibles were removed and processed for radiographic, histological, immunohistochemical, and scanning electron microscopic examinations as well as Ca/P ratio analysis. Group A animals showed greater bone formation and earlier mineralization in the distracted callus when compared with group B. Similarly increased callus formation was found in group B than group C. Positive immunostaining of BMP-7 was observed in the distracted callus in all groups. However, BMP-7 expression was much stronger in group A compared with groups B and C. The results of this study suggest that BMP-7-mediated ex vivo gene transfer based on MSCs may accelerate callus formation in distraction osteogenesis and facilitate consolidation. Local gene therapy may ultimately be an alternative or supplemental approach to DO enhancement, especially for patients whose osteogenic potentials are compromised by diseases such as osteoporosis, severe trauma, and postoncologic irradiation.

Animals↗
PubMed2001

Effect of chemotherapeutic agents on distraction osteogenesis. An experimental investigation in rabbits.

Limb-salvage operations such as vascularised or non-vascularised osseous grafts and allograft and callus distraction methods have replaced amputations because of the increase in the life expectancy of patients with malignant tumours. In this study we aimed to evaluate the effects of chemotherapeutic agents on distraction osteogenesis. For this purpose, 23 rabbits randomly divided into two groups were included in the study. The experimental group and the control group consisted of 12 rabbits and 11 rabbits, respectively. The experimental group were administered chemotherapeutic agents with the protocol identified in the osteogenic sarcoma regimen. All the subjects were corticotomised in the metaphyseal-diaphyseal region, and both groups underwent distraction with a circular ring fixator. X-ray films, bone scintigraphy and histopathological examination were performed three times during the study. No difference between the two groups was observed in radiological, scintigraphical and histopathological studies carried out before the distraction period and following the end of the distraction period. In this study, it was shown that the use of antineoplastic drugs has no significant negative effect on distraction osteogenesis applied for reconstruction in rabbits. We think that it can be an alternative treatment method in humans as well.

Animals↗
PubMed2002

Monitoring of bone formation during distraction osteogenesis via osteocalcin: a time sequence study in dogs.

The aim of the current study was to analyze the osteocalcin level and radiographic density during distraction osteogenesis in order to investigate the role of osteocalcin in monitoring bone formation during callus distraction. Lengthening of the right tibia by 25% was performed in 12 beagle dogs by callus distraction after osteotomy and application of a ring fixator. Distraction was started on the 5th postoperative day, with a distraction rate of 0.5 mm twice a day, and was ended after 25 days. Blood samples and x-rays of the callus distraction segment were obtained preoperatively and once a week until day 55 after operation. A digital radiograph analysis system was used to determine the bone density of the callus distraction segments. The serum parameters of osteocalcin were evaluated by radioimmunoassay. The radiographic bone densities during the distraction phase increased during the distraction period and markedly increased during the consolidation period. A similar trend was observed for osteocalcin, whereby the coefficient of correlation between these two parameters was, on average, 0.68 +/- 0.11. However, the radiographic bone density measurements, as well as the osteocalcin levels, showed large variation between different animals. Therefore, our results suggest that valuable information about bone formation during distraction osteogenesis can be obtained via serum osteocalcin levels, even though it seems that time sequence monitoring is more favorable than the determination of absolute values.

Animals↗
PubMed2005

Evaluation of recombinant human bone morphogenetic protein-2 in mandibular distraction osteogenesis in rabbits: Effect of dosage and number of doses on formation of bone.

We evaluated the dose- and time-dependent response of recombinant human bone morphogenetic protein-2 (rhBMP-2) to the formation of bone in mandibular distraction osteogenesis. Twenty-one adult white New Zealand rabbits (3.0-3.8 kg) were used to establish the mandibular distraction model, 18 of which completed the experiment. Eight rabbits were given rhBMP-2 360 microg and eight 1080 microg; two were given no rhBMP-2. The fluids were injected into the regenerating bone at three different time sequences (days 5, 8, and 11 of active distraction; days 5 and 11 of active distraction; and day 11 of active distraction alone). After four weeks of consolidation, the specimens were harvested and examined radiographically by micro-computed tomography (micro-CT), and histologically. The formation and remodelling of bone in distraction osteogenesis was significantly increased by the addition of rhBMP-2, and the increase was dose-dependent. There was no significant difference between different dosage regimens. A single injection of rhBMP-2 at the end of the distraction phase was as effective as multiple injections.

Animals↗
PubMed2006

Distraction osteogenesis in the irradiated rabbit mandible.

PURPOSE: The potential use of distraction osteogenesis in mandibular reconstruction has been limited by its questionable efficacy in previously radiated bone. The purpose of this study was to evaluate the effects of irradiation on mandibular distraction osteogenesis (DO). MATERIALS AND METHODS: Six rabbits received a unilateral irradiation (group R) in the mandible with a total dose of 27.0 Gy in five 5.4 Gy fractions (equivalent to 50 Gy/25 fractions). The contralateral side served as control (group C). Bilateral osteotomy was made 3 months after completion of irradiation. After a 1-week latency period bone distraction was activated at a rate of 0.5 mm twice daily for 8 days, followed by a consolidation phase of 6 weeks. New bone underwent radiographic, densitometric, histological and histomorphometric analysis. RESULTS: Two rabbits were excluded from the study, one due to infection on both sides and death in another animal. After 6 weeks of consolidation, the irradiation group had no significantly lower BMD than control group. No difference was found between the percent area of new bone in both groups. New bone was more mature and organised of group C than in groups R. Larger chondroid islands were found evident in distracted bone of group R than group C. CONCLUSIONS: It seems that DO can be feasible in previously irradiated rabbit mandible.

Absorptiometry, Photon↗