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At least 721 records · Page 40Linked to original sources
PubMed2000

Experience with Bailey-Dubow rodding in children with osteogenesis imperfecta.

AIM: The current report presents our experience with the use of Bailey-Dubow elongation rods in children with osteogenesis imperfecta. MATERIAL AND METHODS: 63 patients with osteogenesis imperfecta underwent a total of 186 primary intramedullary fixations with Bailey-Dubow rods during period 1984-1996. Most of them were inserted into the femur (54.3 %), followed by the tibia (38.2%) and the humerus (7.9%). Patients' age at operation ranged from 1-12 years and treatment-period varied from 1-10 years. RESULTS: Insertion into the femur showed the lowest complication rate (21.0%). Patients either suffered from knee-joint migration of the distal nail (3.9%), proximal nail migration (7.9%), detached T-pieces from the sleeve (7.9%) or chronical nail infection (1.0%). Complication rate after tibia rodding was markedly higher (52.1%). Knee joint migration appeared in 8.5% and the distal piece of the rod migrated proximally in 38.0%, in 31.0% accompanied by recurrent antecurve deformity. Growth arrest and no elongation occurred in 5.6%. Results after humerus operation were by far least satisfying. None of the nails elongated adequately. 8 of the 14 Bailey-Dubow rods (57.1 %) required reoperation caused by migration and chronic nail infection, whereas reoperation rates amounted to 17.8% after femur and 29.6% after tibia insertion. However, just one refracture happened after adequate trauma (road accident), so that an extraordinary success of fracture prevention has to be scored. CONCLUSIONS: We concluded that the use of Bailey-Dubow rods in early childhood can be recommended for the femur, whereas insertion into the tibia or humerus is associated with a considerable complication rate.

Child↗
PubMed2001

Facial symmetry after distraction osteogenesis and orthodontic therapy.

The purpose of this study was to document changes in the facial symmetry of patients with severe hypoplastic mandibles treated with distraction osteogenesis and orthodontic therapy. Ten patients (5 males and 5 females), ages 7 to 22 years, underwent unilateral mandibular distraction osteogenesis with extraoral distracting devices. Orthodontic therapy was initiated after the completion of mandibular lengthening. The mean follow-up period was 25.5 months. Posteroanterior cephalograms were traced before distraction, 6 months after distraction, and at a later follow-up appointment. Displacement of the chin point (in millimeters) and the midpoint of the mandibular incisors, the piriform angle, the intergonial angle, the occlusal cant to the horizontal line (in degrees), the ratio of linear measurements (in millimeters) Co-Gn, Co-Go, and Go-Gn of the affected to the nonaffected side, CoA'-Mid to CoA-Mid, and GoA'-Mid to GoA-Mid were compared. At the latest follow-up appointment, patients defined as having a successful result had a mean occlusal cant of 1.25 degrees, an intergonial angle of 2.13 degrees, and a piriform angle of 2.63 degrees. The mean displacement of the chin point to the midline was 1.5 mm and that of the mandibular central incisors to the midvertical line was 1.38 mm. The results indicated improvement in all patients.

Adolescent↗
PubMed2000

Growth factor and cytokine gene expression in mechanically strained human osteoblast-like cells: implications for distraction osteogenesis.

OBJECTIVE: An understanding of bone cellular biology is a basic necessity to understanding events such as distraction osteogenesis. The goal of this study was to determine the effect of continuous cyclic mechanical stretch as a fundamental event in distraction osteogenesis on the expression of 3 bone growth factors, transforming growth factor-beta 1 (TGF-beta1), insulin-like growth factor 1 (IGF-1), basic fibroblast growth factor (bFGF) and 2 cytokines, interleukin (IL)-1 (IL-1) and 6 (IL-6) in human osteoblast-like cells. MATERIAL AND METHODS: A human osteoblast-like cell line, SaOS-2, capable of forming a ground substance and mineralizing it, was maintained. Cells were transferred to 6-well plates with flexible silicon bottoms grown to confluence and either subjected to tensile stretch for different time intervals or used as the control group. RNA was isolated to conduct Northern blot analysis for the expression of 3 bone growth factors, transforming TGF-beta1, IGF-1, bFGF, and 2 cytokines, IL-1 and IL-6. RESULTS: After 8 hours, mRNA for TGF-beta1 and IGF-1 increased in the experimental group, whereas bFGF decreased but cytokines IL-1 and IL-6 were not affected. At 16 hours, TGF-beta1, IGF-1, and bFGF showed increased levels of mRNA; IL-6 showed a slight increase. After 24 hours, TGF-beta1, IGF-1, bFGF, and IL-6 had increased mRNA levels. IL-1beta did never show significant alterations in mRNA production as compared with the control. CONCLUSION: Tensile stretch on osteoblast-like cells alter local regulation of bone formation, increasing the expression of bone growth factors, whereas catabolic cytokines are unaffected. These findings suggest a direct effect of mechanical strain on osteoblasts and may be the driving factors of bone growth during distraction.

Blotting, Northern↗
PubMed2003

The use of distraction osteogenesis to treat hemifacial microsomia: a clinical report.

Distraction osteogenesis is a method of forming bone through osteotomy and sequential stretching of the healing callus. This process is accomplished with the aid of a distraction device, which is secured with screws placed directly into bone for a predetermined length of time. This clinical report describes the use of distraction osteogenesis to treat mandibular asymmetry in a patient with Goldenhar's syndrome, a form of hemifacial microsomia. After treatment, the patient had a more rounded facial contour and corrected occlusal plane.

Bone Screws↗
PubMed2002

Isolated allogeneic bone marrow-derived mesenchymal cells engraft and stimulate growth in children with osteogenesis imperfecta: Implications for cell therapy of bone.

Treatment with isolated allogeneic mesenchymal cells has the potential to enhance the therapeutic effects of conventional bone marrow transplantation in patients with genetic disorders affecting mesenchymal tissues, including bone, cartilage, and muscle. To demonstrate the feasibility of mesenchymal cell therapy and to gain insight into the transplant biology of these cells, we used gene-marked, donor marrow-derived mesenchymal cells to treat six children who had undergone standard bone marrow transplantation for severe osteogenesis imperfecta. Each child received two infusions of the allogeneic cells. Five of six patients showed engraftment in one or more sites, including bone, skin, and marrow stroma, and had an acceleration of growth velocity during the first 6 mo postinfusion. This improvement ranged from 60% to 94% (median, 70%) of the predicted median values for age- and sex-matched unaffected children, compared with 0% to 40% (median, 20%) over the 6 mo immediately preceding the infusions. There was no clinically significant toxicity except for an urticarial rash in one patient just after the second infusion. Failure to detect engraftment of cells expressing the neomycin phosphotransferase marker gene suggested the potential for immune attack against therapeutic cells expressing a foreign protein. Thus, allogeneic mesenchymal cells offer feasible posttransplantation therapy for osteogenesis imperfecta and likely other disorders originating in mesenchymal precursors.

Absorptiometry, Photon↗
PubMed1980

A defect in the structure of type I procollagen in a patient who had osteogenesis imperfecta: excess mannose in the COOH-terminal propeptide.

Fibroblasts from normal human subjects and from a patient who had osteogenesis imperfecta were incubated with [3H]mannose, and types I and III procollagens were isolated from the culture medium. The type I procollagen from the patient's fibroblasts contained 2-3 time more [3H]mannose than the type I procollagen from the normal fibroblasts. In contrast, there was no difference in the [3H]mannose content of the type III procollagen simultaneously synthesized and secreted by the same cells. Isolation of a collagenase-resistant peptide fragment from the type I procollagen showed that the excess mannose was located in the COOH-terminal propeptide of the protein. Radioimmunoassays of the medium and the cell layer showed that the type I procollagen synthesized by the patient's fibroblasts was secreted into the medium more slowly than the type I procollagen synthesized by normal fibroblasts. These results appear to provide evidence for an alteration in the structure of procollagen in osteogenesis imperfecta.

Cells, Cultured↗
PubMed1984

Nuclease S1 mapping of a homozygous mutation in the carboxyl-propeptide-coding region of the pro alpha 2(I) collagen gene in a patient with osteogenesis imperfecta.

The molecular defect in a patient with a moderately severe form of osteogenesis imperfecta was characterized by nuclease S1 mapping. Single-stranded 5' and 3' end-labeled DNA probes coding for 80% of the carboxyl-propeptide of the pro alpha 2(I) collagen gene were hybridized to mRNA isolated from cultured fibroblasts of the patient and his parents. Nuclease S1 digestion revealed a homozygous mutation in the patient and a heterozygous pattern in the consanguineous parents. As a result of the defect in the gene, none of the pro alpha 2(I) chains synthesized by the patient's fibroblasts were incorporated into a type I procollagen heterotrimer consisting of two pro alpha 1(I) chains and one pro alpha 2(I) chain. Cultured skin fibroblasts from the patient have previously been shown to secrete only pro alpha 1(I) trimers. As shown here, fibroblasts from both parents, who do not have osteogenesis imperfecta, secrete both pro alpha 1(I) trimers and normal type I procollagen. A further observation was that synthesis of pro alpha 2(I) chains was decreased in fibroblasts from the patient and his parents. The decrease in the synthesis of pro alpha 2(I) chains is not caused by decreased transcription of the pro alpha 2(I) collagen alleles, since the pro alpha 1(I)/pro alpha 2(I) mRNA ratios were normal in the patient and his parents.

Alleles↗
PubMed1985

Intron-mediated recombination may cause a deletion in an alpha 1 type I collagen chain in a lethal form of osteogenesis imperfecta.

To understand the nature of the mutation in type I collagen genes in cells from an infant with the perinatal lethal form of osteogenesis imperfecta (type II), we cloned and sequenced almost 2 kilobases of a normal alpha 1(I) collagen gene and the corresponding region of a mutant alpha 1(I) gene from cell strain CRL 1262. The mutant gene had undergone recombination between two non-homologous introns, which resulted in the loss of three exons coding for 84 amino acids in the triple-helical domain. The deletion predicted the loss of amino acid residues surrounding and including the methionine at the junction between the CNBr peptides alpha 1(I) CB8 and alpha 1(I) CB3, a result confirmed by analysis of the cleavage peptides from the product of the mutant gene. Although large deletions from collagen genes are uncommon causes of the osteogenesis imperfecta type II phenotype, analysis of the de novo change in gene structure in this cell strain suggests that similar rearrangements may have occurred during the evolution of the large collagen genes.

Amino Acid Sequence↗
PubMed1990

Transgenic mouse model of the mild dominant form of osteogenesis imperfecta.

Osteogenesis imperfecta type I is a mild, dominantly inherited, connective tissue disorder characterized by bone fragility. Mutations in type I collagen account for all known cases. In Mov-13 mice, integration of a murine retrovirus within the first intron of the alpha 1(I) collagen gene results in a null allele blocked at the level of transcription. This study demonstrates that mutant mice heterozygous for the null allele are a model of osteogenesis imperfecta type I. A defect in type I collagen production is associated with dominant-acting morphological and functional defects in mineralized and nonmineralized connective tissue and with progressive hearing loss. The model provides an opportunity to investigate the effect of a reduced amount of type I collagen on the structure and integrity of extracellular matrix. It also may represent a system in which therapeutic strategies to strengthen connective tissue can be developed.

Animals↗
PubMed1991

Mutation in a gene for type I procollagen (COL1A2) in a woman with postmenopausal osteoporosis: evidence for phenotypic and genotypic overlap with mild osteogenesis imperfecta.

Mutations in the two genes for type I collagen (COL1A1 or COL1A2) cause osteogenesis imperfecta (OI), a heritable disease characterized by moderate to extreme brittleness of bone early in life. Here we show that a 52-year-old postmenopausal woman with severe osteopenia and a compression fracture of a thoracic vertebra had a mutation in the gene for the alpha 2(I) chain of type I collagen (COL1A2) similar to mutations that cause OI. cDNA was prepared from the woman's skin fibroblast RNA and assayed for the presence of a mutation by treating DNA heteroduplexes with carbodiimide. The results indicated a sequence variation in the region encoding amino acid residues 660-667 of the alpha 2(I) chain. Further analysis demonstrated a single-base mutation that caused a serine-for-glycine substitution at position 661 of the alpha 2(I) triple-helical domain. The substitution produced posttranslational overmodification of the collagen triple helix, as is seen with most glycine substitutions that cause OI. The patient had a history of five previous fractures, slightly blue sclerae, and slight hearing loss. Therefore, the results suggest that there may be phenotypic and genotypic overlap between mild osteogenesis imperfecta and postmenopausal osteoporosis, and that a subset of women with postmenopausal osteoporosis may have mutations in the genes for type I procollagen.

Adult↗
PubMed1998

Marrow stromal cells as a source of progenitor cells for nonhematopoietic tissues in transgenic mice with a phenotype of osteogenesis imperfecta.

Marrow stromal cells from wild-type mice were infused into transgenic mice that had a phenotype of fragile bones resembling osteogenesis imperfecta because they expressed a human minigene for type I collagen. In mice that were irradiated with potentially lethal levels (700 cGy) or sublethal levels (350 cGy), DNA from the donor marrow stromal cells was detected consistently in marrow, bone, cartilage, and lung either 1 or 2.5 mo after the infusions. The DNA also was detected but less frequently in the spleen, brain, and skin. There was a small but statistically significant increase in both collagen content and mineral content of bone 1 mo after the infusion. Similar results were obtained with infusion of relatively large amounts of wild-type whole marrow cells into the transgenic mice. In experiments in which male marrow stromal cells were infused into a female osteogenesis imperfecta-transgenic mouse, fluorescense in situ hybridization assays for the Y chromosome indicated that, after 2.5 mo, donor male cells accounted for 4-19% of the fibroblasts or fibroblast-like cells obtained in primary cultures of the lung, calvaria, cartilage, long bone, tail, and skin. In a parallel experiment in which whole marrow cells from a male mouse were infused into a female immunodeficient rag-2 mouse, donor male cells accounted for 4-6% of the fibroblasts or fibroblast-like cells in primary cultures. The results support previous suggestions that marrow stromal cells or related cells in marrow serve as a source for continual renewal of cells in a number of nonhematopoietic tissues.

Animals↗
PubMed2004

Unexpected events during mandibular distraction osteogenesis.

Various unexpected events during mandibular distraction osteogenesis are described in 16 syndromic children with severely retrognathic or asymmetric lower jaws who were treated with unilateral or bilateral extraoral distraction. The mean total time with the distraction devices attached was 14 weeks (range 10-19). Although improvement in facial aesthetics and the desired occlusion was achieved in all but one case, there were unexpected events associated with mandibular distraction. These included pain not related to the operation, functional disturbance in movement of the jaw, dietary problems, weight loss, unfulfilled expectations of decannulation, temporary unilateral facial nerve palsy, and transient unilateral hypoaesthesia of the inferior alveolar nerve. Reoperation was required in 5 of the 16. In addition to these events, psychosocial problems within one family complicated the procedure. Patients and their families should be informed of the lesser-known aspects of distraction osteogenesis before the procedure is used.

Adolescent↗
PubMed2002

Geometry of artificial ECM: sizes of pores controlling phenotype expression in BMP-induced osteogenesis and chondrogenesis.

This study aims to elucidate the feasible geometry of the scaffolds in bone and periodontal tissue engineering. Several biomaterials with different geometries are compared in terms of their patterns of ectopic BMP-induced chondrogenesis and osteogenesis. The materials include a honeycomb-shaped hydroxyapatite (HCHAP) with different tunnel sizes, a laser-perforated collagen membrane (LPM), and CPSA bioglass fibers. Implanted pellets were removed at 1-4 weeks and analyzed for bone and cartilage formation histologically and biochemically. Porous particles of hydroxyapatite (PPHAP), porous blocks of hydroxyapatite (PBHAP), and LPM did not induce detectable cartilage formation. In straight tunnel structures with various diameters in honeycomb-shaped hydroxyapatite (HCHAP), tunnels with smaller diameters (approximately 0.1 mm) induced cartilage followed by bone formation, while one with a larger diameter (0.35 mm) directly induced bone formation within the tunnels. It is concluded that the "vasculature-inducing geometry" of the carrier as an ECM is crucially important for osteogenesis.

Animals↗
PubMed1983

Calcitonin and calcium therapy in an infant with osteogenesis imperfecta congenita.

Calcitonin has been helpful in the treatment of osteogenesis imperfecta tarda inhibiting bone mineral resorption. The experience with salmon calcitonin in the early treatment of osteogenesis imperfecta congenita is very limited. Here we report an infant with this disorder treated with calcitonin from 3 to 15 months of age with clinical and radiographic improvement.

Bone Resorption↗
PubMed2003

Mandibular lengthening by distraction osteogenesis for treatment of obstructive sleep apnea syndrome: a case report.

A 31-year-old man who had been diagnosed with obstructive sleep apnea syndrome (OSAS) due to retrognathia was referred to our hospital. Before treatment, the angle of the sella-nasion-point B (SNB) was 67 degrees. The lowest oxygen saturation (SpO2) during sleep was 77%, the longest-running episode of sleep apnea was 128 seconds, and his apnea index (AI) was 29.9. He underwent bilateral horizontal mandibular distraction osteogenesis using intraoral distraction devices. After mandibular distraction, SNB increased to 72 degrees. The lowest SpO2 during sleep increased to 85%, the longest-running episode of sleep apnea decreased to 40 seconds, and his AI decreased to 4.1 (within normal range). No marked recurrence of OSAS was observed even at one year after mandibular distraction. This report suggests that mandibular lengthening by distraction osteogenesis is an effectual method for the treatment of OSAS due to retrognathia.

Adult↗
PubMed2006

FGF-2 inhibits osteogenesis in mouse adipose tissue-derived stromal cells and sustains their proliferative and osteogenic potential state.

In addition to adult bone marrow-derived mesenchymal stem cells, more recently, a second large stromal compartment found in adipose tissue has received attention and is believed to contain multipotent cells. In vitro, adipose tissue-derived stromal cells (ADS) can differentiate down osteogenic, chondrogenic, myogenic, adipose, and even neuronal pathways. In this article, we explore the effect of fibroblast growth factors 2 (FGF-2) on ADS cells. Our results demonstrated that FGF-2 inhibits osteogenesis in ADS cells. The osteogenic inhibitory effects is dose-dependent and reversible, thus suggesting that the lack of osteogenesis observed in ADS cells exposed to FGF-2 is not due to a negative selection triggered by this factor on a subpopulation of osteoblast progenitors. Furthermore, either overexpression of FGF-2, or continuous FGF-2 treatment sustain the proliferative and osteogenic potential state of ADS cells. Therefore, FGF-2 appears to be a positive regulator of osteoprogenitor cells and a negative regulator of osteoblast differentiation in ADS cells. These FGF-2 functional characteristics may assist with cell selection and enrichment for the purpose of bone tissue engineering.

Adipose Tissue↗
PubMed2006

Suppression of genes related to hypertrophy and osteogenesis in committed human mesenchymal stem cells cultured on novel nitrogen-rich plasma polymer coatings.

Mesenchymal stem cells (MSCs) are pluripotent progenitor cells with the ability to generate cartilage, bone, muscle, tendon, ligament, and fat. However, recent evidence indicates that a major drawback of current cartilage- and intervertebral disc-tissue engineering is that human MSCs isolated from some arthritic patients (a clinically relevant source of stem cells) express type X collagen (a marker of chondrocyte hypertrophy associated with endochondral ossification) and osteogenic markers. Some studies have attempted to use growth factors to inhibit type X collagen expression, but none has addressed the possible effect of the chemical composition of the substratum on chondrocyte hypertrophy and osteogenesis. Here, we examine the growth and differentiation potential of human MSCs cultured on nitrogen (N)-rich plasma polymer layers (N-doped plasma-polymerized ethylene, containing up to 36% nitrogen; PPE:N). We show that PPE:N almost completely suppresses the expression not only of type X collagen, but also of osteogenic marker genes such as alkaline phosphatase, bone sialoprotein, and osteocalcin. In contrast, neither aggrecan nor type I collagen expression were significantly affected. These results indicate that PPE:N coatings may be suitable surfaces for inducing MSCs to a chondrocyte or disc-like phenotype for tissue engineering of cartilage or intervertebral discs, in which hypertrophy and osteogenesis are suppressed.

Aged↗
PubMed1984

Occurrence of malignant hyperpyrexia in a patient with osteogenesis imperfecta.

Probable malignant hyperpyrexia (MH) developed and was successfully treated in a 20-yr-old man during anaesthesia for reduction of a fractured mandible. The sister of this patient had died after an anaesthetic at the age of 14 yr, but malignant hyperpyrexia was not suspected. Subsequent enquiries revealed that the patient and his sister both had osteogenesis imperfecta. This case illustrates the infrequently reported association of malignant hyperpyrexia with osteogenesis imperfecta, and the difficulties in obtaining an adequate personal and family history of previous anaesthetics.

Adolescent↗