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1.
Nature ; 444(7119): 566, 2006 Nov 30.
Article in English | MEDLINE | ID: mdl-17136085

ABSTRACT

Regular, moderate consumption of red wine is linked to a reduced risk of coronary heart disease and to lower overall mortality, but the relative contribution of wine's alcohol and polyphenol components to these effects is unclear. Here we identify procyanidins as the principal vasoactive polyphenols in red wine and show that they are present at higher concentrations in wines from areas of southwestern France and Sardinia, where traditional production methods ensure that these compounds are efficiently extracted during vinification. These regions also happen to be associated with increased longevity in the population.


Subject(s)
Biflavonoids/analysis , Catechin/analysis , Proanthocyanidins/analysis , Vascular Diseases/prevention & control , Wine , Aged , Biflavonoids/chemistry , Biflavonoids/pharmacology , Catechin/chemistry , Catechin/pharmacology , Cells, Cultured , Endothelin-1/biosynthesis , Endothelium, Vascular , Female , France , Humans , Longevity , Male , Proanthocyanidins/chemistry , Proanthocyanidins/pharmacology , Protective Agents/analysis , Protective Agents/pharmacology
2.
Crit Rev Eukaryot Gene Expr ; 13(2-4): 205-20, 2003.
Article in English | MEDLINE | ID: mdl-14696968

ABSTRACT

Osteoactivin (OA) is more highly expressed in the bones of osteopetrotic mutant rats (op/op) than in those of their normal littermates and is the homologue of human nmb, a cDNA more highly expressed in melanoma-derived cell lines of low metastatic potential, and of mouse DC-HIL, which has been implicated in endothelial cell adhesion. The human OA gene is found on chromosome 7p15.1 and consists of 11 exons spanning 28.3 kb. Murine OA is encoded by a highly similar gene of 11 exons spanning 20.2 kb on mouse chromosome 6. Human OA uses the same transcriptional initiation site in both bone and kidney as was reported for melanoma cells. OA is expressed in primary human and mouse osteoblast cultures at all stages of differentiation, with increased levels observed concurrently with the expression of osteoblast phenotype markers. OA is also expressed in a wide variety of human and mouse tissues as determined by RT-PCR analysis. Immunohistochemical investigation of OA expression in late mouse embryonic development showed very high, cell-specific expression in the nervous system, basal layer of the skin, germinal cells of hair follicles, and in the forming nephrons of the kidney. Continuing investigation of the cell-specific expression of OA in bone as well as in other tissues will lead to a better understanding of its function in the development of these cell types.


Subject(s)
Protein Biosynthesis , Proteins/genetics , Amino Acid Sequence , Animals , Bone and Bones/metabolism , Cell Adhesion , Cell Differentiation , Cells, Cultured , Chromosome Mapping , Chromosomes, Human, Pair 6/genetics , DNA, Complementary/metabolism , Databases as Topic , Exons , Humans , Immunohistochemistry , In Situ Hybridization, Fluorescence , Introns , Kidney/metabolism , Membrane Glycoproteins , Mice , Models, Genetic , Molecular Sequence Data , Mutation , Osteoblasts/metabolism , Osteopetrosis , RNA, Messenger/metabolism , Radiation Hybrid Mapping , Rats , Reverse Transcriptase Polymerase Chain Reaction , Sequence Homology, Amino Acid , Time Factors , Tissue Distribution , Transcription, Genetic
3.
Bone ; 33(4): 638-45, 2003 Oct.
Article in English | MEDLINE | ID: mdl-14555269

ABSTRACT

OBJECTIVE: To investigate the effects of growth hormone (GH) replacement therapy on bone matrix gene expression of insulin-like growth factors (IGFs) and markers of bone metabolism in women with adult-onset GH deficiency (GHD). DESIGN AND METHODS: Nineteen women, mean age 45 (range 24-56) years, were included in a double-blind, placebo-controlled parallel group study for 12 months. Biochemical markers were measured at baseline, 6 and 12 months. Bone biopsies were obtained and BMD was measured at baseline and after 12 months. RESULTS: Maximum responses were observed after 6 and 12 months, for bone resorptive and bone formative markers respectively. GH therapy enhanced gene expression in cortical bone of IGFs, GH-and calcitonin-receptor (CR) and osteoprotegerin (OPG), however with the most pronounced effects on CR and IGF-I. Changes in IGF-I gene expression during longitudinal follow-up were significantly correlated with changes in both circulating IGF-I (r = 0.82, p < 0.05), changes in markers of enhanced osteoclastic activity, measured both locally in bone (CR, r = 0.87, p < 0.01) and in serum (CTX-I, r = 0.86, p < 0.05), as well as serum bone ALP (r = 0.96, p < 0.01). CONCLUSIONS: This study indicates that both liver- and bone-derived IGF-I may be significant in mediating the effects of GH on bone metabolism in humans.


Subject(s)
Bone and Bones/drug effects , Bone and Bones/metabolism , Human Growth Hormone/deficiency , Human Growth Hormone/therapeutic use , Somatomedins/genetics , Adult , Base Sequence , Bone Remodeling/drug effects , Bone Remodeling/genetics , DNA/genetics , Female , Gene Expression/drug effects , Glycoproteins/blood , Humans , Insulin-Like Growth Factor Binding Protein 3/genetics , Insulin-Like Growth Factor I/genetics , Middle Aged , Osteoprotegerin , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, Cytoplasmic and Nuclear/blood , Receptors, Tumor Necrosis Factor , Recombinant Proteins/therapeutic use , Reverse Transcriptase Polymerase Chain Reaction
4.
Tissue Cell ; 34(2): 103-8, 2002 Apr.
Article in English | MEDLINE | ID: mdl-12165245

ABSTRACT

The osteopetrosis (op) mutation in mice is characterized by generalized skeletal sclerosis; reduced numbers of osteoclasts, macrophages, and monocytes; and failure to be cured by bone marrow transplantation. This mutation has been shown to result from an absence of colony-stimulating factor-1 (CSF-1) and reported to be cured by treatment with CSF-1. Macrophage polykaryons are known to be formed by fusion of mononuclear precursors and the presence of subcutaneous implants can elicit the formation of macrophage polykaryons. In order to determine if recruitment of foreign body giant cells is also impaired in osteopetrotic mice, tissue reactions to subcutaneously implanted polyvinyl sponges were studied and compared with normal mice. Our result showed that, in the op mouse, recruitment of macrophages and foreign body giant cells in response to the implants was quantitatively not different from that of normal mice. However, these cells were smaller and did not migrate as deeply into the implant as those seen in normal littermates. In contrast, resident macrophages obtained by peritoneal lavage were significantly reduced in op mice. These data indicate that there is a deficiency in the ability of op mice to mount a foreign body giant cell response to an implanted sponge characterized by a deficiency in the recruitment of precursor cells that are capable of either full development and spreading or migration into the implanted sponge. These data add to the emerging appreciation of the regional differences among macrophage populations in their dependence on CSF-1 for differentiation and survival.


Subject(s)
Giant Cells, Foreign-Body/physiology , Implants, Experimental , Macrophage Colony-Stimulating Factor/deficiency , Osteopetrosis/physiopathology , Animals , Cell Count , Female , Giant Cells, Foreign-Body/immunology , Homozygote , Macrophage Colony-Stimulating Factor/genetics , Macrophages/immunology , Macrophages/physiology , Male , Mice , Mice, Knockout , Polyvinyls , Porifera
5.
Bone ; 31(2): 282-7, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12151080

ABSTRACT

Tooth eruption involves the movement of a tooth from its site of development within the alveolar bone to its functional position in the oral cavity. Because this process is dependent upon monocytes and formation of osteoclasts, it represents an excellent model for examination of these processes under developmental regulation. We investigated the functional role of monocyte chemoattractant protein-1 (MCP-1) in monocyte recruitment and its impact on bone resorption by examining each parameter in MCP-1(-/-) mice as compared with wild-type controls during tooth eruption. The peak number of monocytes occurred on day 5 in the MCP-1(-/-) mice and on day 9 in the wild-type mice. The peak number of osteoclasts followed the same pattern, occurring sooner in the MCP-1(-/-) (day 5) than in wild-type mice (day 9). Consistent with this, MCP-1(-/-) mice had an accelerated rate of tooth eruption in the early phase when the teeth first entered the oral cavity as compared with the wild-type mice. However, there was accelerated eruption in the wild-type group in the later phase of tooth eruption. When examined at the molecular level, inducible nitric oxide synthase (iNOS) and interleukin-11 and -6 were expressed at considerably higher levels in the experimental group with accelerated tooth eruption. This is the first report identifying these factors as potential modulators of bone resorption that can accelerate the rate of tooth eruption. We conclude that, at early timepoints, monocyte recruitment occurs by MCP-1-independent mechanisms. However, at a later timepoint, MCP-1 may play a contributory role in the recruitment of monocytic cells, allowing the wild-type animals to catch up.


Subject(s)
Bone Resorption/genetics , Bone Resorption/metabolism , Chemokine CCL2/deficiency , Chemokine CCL2/genetics , Gene Deletion , Gene Expression Regulation, Developmental/physiology , Monocytes/metabolism , Animals , Animals, Newborn , Mice , Mice, Inbred C57BL , Mice, Knockout , Tooth Eruption/genetics , Tooth Eruption/physiology
6.
J Bone Miner Res ; 17(6): 991-7, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12054175

ABSTRACT

Tooth eruption is characterized by spatially segregated bone resorption along the path of eruption and bone formation in the opposite direction. Monocyte recruitment occurs in two distinct peaks in both areas of resorption and formation. Without such recruitment tooth eruption does not occur. The signals that regulate this recruitment are thought to involve the expression of cytokines and chemokines. One such cytokine is tumor necrosis factor (TNF), which can affect monocyte recruitment through the induction of chemokines and adhesion molecules and increase their lifespan by acting as antiapoptotic cell survival signals. We examined the latter by studying mice with targeted deletions of TNF receptors p55 and p75 (TNFRp55/p75). The results indicate that mice that lack functional TNF receptors have a significantly reduced number of monocytes in the apical area associated with bone formation. The reduced number of monocytes in this area can be accounted for by an increase in apoptosis in TNFRp55-/-/p75-/-. In contrast, the number of monocytes, the rate of monocyte apoptosis, and the formation of osteoclasts in the occlusal area associated with bone resorption occurred independently of TNF activity. These results suggest that TNF receptor signaling can affect tooth eruption by acting as a monocyte survival signal in some but not all areas of bone undergoing developmentally regulated remodeling.


Subject(s)
Apoptosis/physiology , Bone Remodeling , Monocytes/cytology , Tumor Necrosis Factor-alpha/physiology , Animals , Antigens, CD/genetics , Antigens, CD/physiology , Immunohistochemistry , Mice , Mice, Transgenic , Receptors, Tumor Necrosis Factor/genetics , Receptors, Tumor Necrosis Factor/physiology , Receptors, Tumor Necrosis Factor, Type I , Receptors, Tumor Necrosis Factor, Type II , Tooth Eruption
7.
Microcirculation ; 8(5): 347-54, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11687946

ABSTRACT

OBJECTIVE: Class 6 chronic venous stasis is associated with abnormal venous hemodynamics and ulceration. Ulcers primarily occur over bones and tendon prominences but very rarely over muscular compartments. We hypothesized that the anatomical distribution of venous stasis ulcers in the lower extremity is related to a lower density of venous valves. METHODS: The venous vasculature of six normal human legs was cast with resin, and their microvenous valvular anatomy was examined. Skin samples were obtained from the skin overlying the 1) Achilles' tendon, 2) anterior tibia, 3) medial malleolus, 4) lateral malleolus, 5) dorsal surface of the foot, 6) planta pedis, 7) dorsal aspect of the great toe; and from the skin regions overlying the 8) gastrocnemius, 9) tibialis anterior, and 10) peroneus muscles. The valvular and venous densities were determined in a scanning electron microscope, normalized to the size of specimens, and the valvular index was calculated. Analysis of variance with Bonferroni t-test was used to compare the valvular index between the regions. RESULTS: Venous valves were observed in all tissue regions. The diameter of veins with valves ranged from 18 microm to 803 microm. The valvular index for regions overlying bones/tendons (i.e., regions 1-7) was significantly higher versus those overlying muscular regions (i.e., regions 8-10) (p < 0.05). The valvular index was not different (p = 0.51) when regions 1 and 2 (where ulcers almost never occur) were compared to regions 3, 4, 5, 6, and 7 (where ulcers frequently occur); nor were there differences between the vascular indexes of regions overlying muscle. The largest venous valves were observed in the plantar region, and the smallest-sized ones were present in the peroneal region. CONCLUSIONS: This study shows that the density of venous valves is actually higher in regions of the human lower extremity overlying bones and tendons, where venous stasis ulcers are common, than those overlying muscular areas, where ulcers are rarely seen. Thus, valvular quantity alone cannot account for the higher clinical incidence of ulceration. It is likely that muscular pumping and/or valvular quality are important factors in preventing the development of venous stasis and ulceration in the lower extremity.


Subject(s)
Leg/blood supply , Varicose Ulcer/etiology , Venous Insufficiency/etiology , Aged , Aged, 80 and over , Chronic Disease , Corrosion Casting , Femoral Artery/pathology , Humans , Male , Microcirculation/pathology , Microscopy, Electron, Scanning , Middle Aged , Skin/blood supply , Varicose Ulcer/pathology , Venous Insufficiency/pathology
8.
Laryngoscope ; 111(9): 1558-64, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11568604

ABSTRACT

OBJECTIVES: Local control and 5-year survival rates are similar for patients undergoing total laryngectomy and supracricoid laryngectomy for the treatment of advanced-stage laryngeal carcinoma. However, comprehensive studies of functional outcomes after supracricoid laryngectomy are lacking. STUDY DESIGN: Cohort study. METHODS: This investigation provides objective voice laboratory data, skilled listener impressions of voice samples, swallowing evaluations, and patient self-perceptions of speech ability obtained from 10 supracricoid laryngectomees. RESULTS: Results demonstrated variable acoustic and speech aerodynamic disturbances, hoarse-breathy vocal quality, and speech dysfluency. Patients' self-perceptions of voice revealed severe dysphonia that induced certain emotional, physical, and functional setbacks. However, blinded judges rated these individuals as possessing intelligible speech and communication skills. All patients demonstrated premature spillage of the bolus and varying degrees of laryngeal penetration, aspiration, and retention during swallowing studies. However, each patient used a compensatory strategy to protect the airway. Voice and swallowing abilities appeared to depend on the mobility of the arytenoid cartilages, base of tongue action, and residual supraglottic tissue for the creation of a competent neoglottal sphincter complex that vibrated during phonation efforts and protected the airway during deglutition. CONCLUSIONS: Supracricoid laryngectomy avoids the potential complications, limitations, and emotional problems associated with a permanent tracheostoma. All patients demonstrated intelligible voice and effective swallowing function postoperatively, supporting supracricoid laryngectomy as a suitable alternative surgical approach to the total laryngectomy in select patients.


Subject(s)
Cricoid Cartilage/surgery , Laryngeal Neoplasms/surgery , Laryngectomy/methods , Laryngectomy/standards , Adult , Aged , Deglutition Disorders/diagnosis , Deglutition Disorders/etiology , Female , Follow-Up Studies , Humans , Laryngeal Neoplasms/mortality , Laryngeal Neoplasms/pathology , Laryngeal Neoplasms/physiopathology , Laryngectomy/adverse effects , Laryngectomy/psychology , Laryngoscopy , Male , Middle Aged , Neoplasm Staging , Patient Selection , Single-Blind Method , Speech Acoustics , Speech Disorders/diagnosis , Speech Disorders/etiology , Survival Analysis , Tracheostomy/adverse effects , Treatment Outcome , Videotape Recording , Voice Disorders/diagnosis , Voice Disorders/etiology
9.
Arch Otolaryngol Head Neck Surg ; 127(6): 665-9, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11405865

ABSTRACT

BACKGROUND: Severely comminuted frontal sinus fractures are difficult to contour and immobilize. Frequently, plates or wires are inadequate in fixating all fragments together, resulting in less than optimal outcomes. Advancements in the development of biomaterials have now made titanium mesh a new option for the repair of severely comminuted fractures. METHODS: Fourteen patients with severely comminuted frontal sinus fractures were treated with titanium mesh from 1994 to 1999. The fractures were reduced and immobilized using a simple algorithm: (1) Isolated anterior table fractures were repaired with reduced bony fragments attached to titanium mesh. (2) Anterior table fractures with nasofrontal duct involvement were repaired by sinus obliteration and anterior wall reconstruction with reduced bony fragments attached to titanium mesh. (3) Anterior and posterior table fractures with cerebrospinal fluid leak or displacement were treated with the cranialization of the sinus and anterior wall reconstruction with reduced bony fragments attached to titanium mesh. RESULTS: Of the 14 patients treated, 12 were available for postoperative evaluation. Parameters such as nasal function, cranial nerve V and VII function, cosmesis, and complications (hardware extrusions, sinusitis, meningitis, osteomyelitis, mucopyocele, brain abscess, pneumocephalus, and cerebrospinal fluid leak) were evaluated. All patients had good function of the superior division of cranial nerves V and VII. Two patients (16%) had minor wound infections, which resolved under treatment with antibiotics. All had excellent cosmetic results as measured by postreduction radiographs and personal and family perceptions of forehead contour. CONCLUSION: Titanium mesh reconstruction of severely comminuted frontal sinus fractures has few complications while providing excellent forehead contour and cosmesis.


Subject(s)
Fractures, Comminuted/surgery , Frontal Sinus/injuries , Skull Fractures/surgery , Surgical Mesh , Adult , Algorithms , Fracture Fixation, Internal , Humans , Middle Aged , Titanium/therapeutic use
10.
Am J Otolaryngol ; 22(3): 167-71, 2001.
Article in English | MEDLINE | ID: mdl-11351284

ABSTRACT

PURPOSE: Management of the carotid artery involved with metastatic squamous cell carcinoma continues to be a topic of much discussion. Early reports, for the most part, focused on the sequel of ligation and the development of various tests to predict patient tolerance for the procedure. More recent alternatives have described resection reconstruction in multistage procedures. By using immediate reconstruction with autogenous arterial grafting, carotid artery resection can be accomplished in patients with radiation failure in a single stage. This technique can be used without the addition of myocutaneous flaps, controlled fistulas, or intracranial surgery advocated for usage with alternative techniques. PATIENTS AND METHODS: Immediate reconstruction after resection of the carotid artery with superficial femoral arterial graft is described. RESULTS: In a series of 18 high-risk patients with radiation failure, the artery was successfully resected and reconstructed in 1 stage without any neurologic or vascular complications. The technique has been associated with prolonged survival in selected patients. CONCLUSION: Carotid artery resection and immediate reconstruction can be performed in high-risk radiation failure patients with acceptable complications, and is associated with prolonged survival in selected cases.


Subject(s)
Carcinoma, Squamous Cell/secondary , Carcinoma, Squamous Cell/surgery , Carotid Arteries/surgery , Head and Neck Neoplasms/secondary , Head and Neck Neoplasms/surgery , Neurosurgical Procedures/methods , Carcinoma, Squamous Cell/radiotherapy , Carotid Arteries/radiation effects , Combined Modality Therapy , Head and Neck Neoplasms/radiotherapy , Humans , Radiotherapy/adverse effects , Salvage Therapy/methods , Surgical Flaps , Time Factors
12.
Int J Dev Biol ; 45(8): 853-9, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11804028

ABSTRACT

The toothless (tl) osteopetrotic mutation in the rat affects an osteoblast-derived factor that is required for normal osteoclast differentiation. Although the genetic locus remains unknown, the phenotypic impact of the tl mutation on multiple systems has been well characterized. Some of its actions are similar to tumornecrosis factor superfamily member 11(TNFSF11; also called TRANCE, RANKL, ODF and OPGL) null mice. TNFSF11 is a recently described member of the tumor necrosis factor superfamily which, when expressed by activated T cells, enhances the survival of antigen-presenting dendritic cells, and when expressed by osteoblasts, promotes the differentiation and activation of osteoclasts. The skeletal similarities between tl rats and TNFSF11(-/-) mice include 1) profound osteoclastopenia (TNFSF11-null mice, 0% and tl rats 0-1% of normal); 2) persistent, non-resolving osteopetrosis that results from 3) a defect not in the osteoclast lineage itself, but in an osteoblast-derived, osteoclastogenic signal; and 4) a severe chondrodysplasia of the growth plates of long bones not seen in other osteopetrotic mutations. The latter includes thickening of the growth plate with age, disorganization of chondrocyte columns, and disturbances of chondrocyte maturation. These striking similarities prompted us to undertake studies to rule in or out a TNFSF11 mutation in the tl rat. We looked for expression of TNFSF11 mRNA in tl long bones and found it to be over-expressed and of the correct size. We also tested TNFSF11 protein function in the tl rat. This was shown to be normal by flow cytometry experiments in which activated, spleen-derived T-cells from tl rats exhibited normal receptor binding competence, as measured by a recombinant receptor assay. We also found that tl rats develop histologically normal mesenteric and peripheral lymph nodes, which are absent from TNFSF11-null mice. Next, we found that injections of recombinant TNFSF11, which restores bone resorption in null mice, had no therapeutic effect in tl rats. Finally, gene mapping studies using co-segregation of polymorphic markers excluded the chromosomal region containing the TNFSF11 gene as harboring the mutation responsible for the tl phenotype. We conclude that, despite substantial phenotypic similarities to TNFSF11(-/-) mice, the tl rat mutation is not in the TNFSF11 locus, and that its identification must await the results of further studies.


Subject(s)
Bone Resorption/genetics , Carrier Proteins/genetics , Membrane Glycoproteins/genetics , Osteopetrosis/genetics , Animals , Bone Resorption/physiopathology , Chromosome Mapping , Chromosomes , Flow Cytometry , Humans , Lymph Nodes/pathology , Mice , Mice, Knockout , Osteoclasts/pathology , Osteopetrosis/pathology , Phenotype , RANK Ligand , Rats , Receptor Activator of Nuclear Factor-kappa B , Tumor Necrosis Factor-alpha
13.
Clin Anat ; 13(6): 448-52, 2000.
Article in English | MEDLINE | ID: mdl-11111898

ABSTRACT

The purposes of medical education can be summarized as learning how to take an effective history, perform a physical examination, and perform diagnostic and therapeutic procedures with minimal risk and maximal benefit to patients. Because patients are three-dimensional (3-D) objects, health care and medical education involve learning and applying 3-D information. The foundation begins in anatomy where students form and confirm or reform their own 3-D ideas and images of the development and structure of the human body at all levels of organization. Students go on to understand the interdependence of structure and function in health and disease. The basic questions for those teaching anatomy are "How do we learn and use 3-D information?" and "How is it taught most effectively?" These are not easy questions for teachers and are rarely asked by those who currently defend or reframe curricula. Unfortunately, there is little information on how we learn 3-D information and no evidence-based literature on the relative long-term vocational effectiveness of methods for teaching it. It is clear that we learn in several distinct modalities and that our students represent a spectrum of learning styles. To support the 3-D learning essential to both medical education and health care, anatomical societies need to provide answers to the following questions: Do the opportunities of dissection (visual, tactile, time, discovery, group process, mentoring) contribute to short- and long-term learning of 3-D information? If so, how? Does dissection offer significant advantages over other methods for learning, confirming, and using 3-D information in anatomy? Answers to these questions will provide a rational basis for decisions about curricular changes in anatomy courses (if, where, and when dissection should occur). This, in turn, will link these changes to society's ultimate purposes for medical education and health care rather than to the fiscal concerns of the businesses of health care and medical education, which is the current practice.


Subject(s)
Anatomy/education , Dissection , Learning , Curriculum , Delivery of Health Care , Education, Medical, Undergraduate , Humans
14.
J Bone Miner Res ; 15(10): 1905-11, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11028442

ABSTRACT

Bone mineral density (BMD) and mechanical strength generally show strong positive correlations. However, osteopetrosis is a metabolic bone disease with increased skeletal density radiographically and increased risk of fracture. We have evaluated mechanical strength and mineral density in three osteopetrotic mutations in the rat (incisors-absent [ia/ia], osteopetrosis [op/op], and toothless [tl/tl]) to test the hypothesis that reduced bone resorption in one or more of these mutations results in weaker bones in the presence of greater mineral density and skeletal mass. Peripheral quantitative computed tomography (pQCT) was used to analyze BMD and cross-sectional geometry in the tibial diaphysis and metaphysis as well as the femoral diaphysis and femoral neck. The bending breaking force of tibial and femoral midshafts was obtained using the three-point bending test and femoral neck strength was tested by axial loading. Osteopetrotic mutants were significantly smaller than their normal littermates (NLMs) in each stock. The pQCT analysis showed that BMD and bone mineral content (BMC) were higher than or equal to NLMs in all skeletal sites measured in the osteopetrotic mutants. However, the mechanical breaking force was equal to or lower than their NLMs in all sites. The cross-sectional structure of long bone shafts was markedly different in osteopetrotic mutants, having a thin cortex and a medullary area filled with primary trabecular bone. These results indicate that osteopetrotic mutations in the rat increase bone density and decrease bone strength. The tibial diaphysis was significantly weaker in tl/tl and ia/ia mutants and the tibial metaphysis showed the greatest increase in BMD in all mutants. These data are another illustration that an increased BMD does not necessarily lead to stronger bones.


Subject(s)
Bone Density/physiology , Leg Bones/physiopathology , Mutation/genetics , Osteopetrosis/genetics , Osteopetrosis/physiopathology , Tensile Strength/physiology , Animals , Body Weight , Bone Resorption/complications , Bone Resorption/diagnostic imaging , Bone Resorption/genetics , Bone Resorption/physiopathology , Diaphyses/diagnostic imaging , Diaphyses/physiopathology , Femur/diagnostic imaging , Femur/physiopathology , Fractures, Bone/complications , Fractures, Bone/diagnostic imaging , Fractures, Bone/genetics , Fractures, Bone/physiopathology , Histocytochemistry , Leg Bones/diagnostic imaging , Osteopetrosis/complications , Osteopetrosis/diagnostic imaging , Phenotype , Rats , Rats, Mutant Strains , Stress, Mechanical , Tibia/diagnostic imaging , Tibia/physiopathology , Tomography, X-Ray Computed
15.
Proc Natl Acad Sci U S A ; 97(20): 10905-10, 2000 Sep 26.
Article in English | MEDLINE | ID: mdl-10984520

ABSTRACT

Tumor necrosis factor-related, activation-induced cytokine (TRANCE), a tumor necrosis factor family member, mediates survival of dendritic cells in the immune system and is required for osteoclast differentiation and activation in the skeleton. We report the skeletal phenotype of TRANCE-deficient mice and its rescue by the TRANCE transgene specifically expressed in lymphocytes. TRANCE-deficient mice showed severe osteopetrosis, with no osteoclasts, marrow spaces, or tooth eruption, and exhibited profound growth retardation at several skeletal sites, including the limbs, skull, and vertebrae. These mice had marked chondrodysplasia, with thick, irregular growth plates and a relative increase in hypertrophic chondrocytes. Transgenic overexpression of TRANCE in lymphocytes of TRANCE-deficient mice rescued osteoclast development in two locations in growing long bones: excavation of marrow cavities permitting hematopoiesis in the marrow spaces, and remodeling of osteopetrotic woven bone in the shafts of long bones into histologically normal lamellar bone. However, osteoclasts in these mice failed to appear at the chondroosseous junction and the metaphyseal periosteum of long bones, nor were they present in tooth eruption pathways. These defects resulted in sclerotic metaphyses with persistence of club-shaped long bones and unerupted teeth, and the growth plate defects were largely unimproved by the TRANCE transgene. Thus, TRANCE-mediated regulation of the skeleton is complex, and impacts chondrocyte differentiation and osteoclast formation in a manner that likely requires local delivery of TRANCE.


Subject(s)
Bone and Bones/physiology , Carrier Proteins/physiology , Enhancer Elements, Genetic/physiology , Lymphocytes/physiology , Membrane Glycoproteins/physiology , Animals , Cell Differentiation/physiology , Cytokines/physiology , Mice , Mice, Transgenic , Osteopetrosis/genetics , Osteopetrosis/physiopathology , RANK Ligand , Receptor Activator of Nuclear Factor-kappa B , Tumor Necrosis Factor-alpha/physiology
17.
Clin Orthop Relat Res ; (377): 241-7, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10943208

ABSTRACT

In mammalian osteopetrosis the different mutations exemplify reduced bone resorption leading to net accumulation of bone. Recently, high blood levels of creatine kinase-BB have been reported in some human forms, suggesting it as a marker of osteopetrosis. In the current study serum creatine kinase-BB was evaluated in relation to known osteoclastic pathophysiology in two human types of autosomal dominant osteopetrosis at baseline and after stimulation with triiodothyronine and in four different rodent mutations. Creatine kinase-BB was increased markedly in Type 2 autosomal dominant osteopetrosis and in the incisors absent rat, both characterized by large numbers of giant osteoclasts, and did not change significantly after stimulation. Although creatine kinase-BB was unchanged in Type 1 autosomal dominant osteopetrosis at baseline and after stimulation, the rodent counterparts characterized by small osteoclasts, microphthalmic and osteopetrotic mice and toothless rats, had significantly decreased levels. Similar differences were observed in both types of autosomal dominant osteopetrosis compared with controls concerning tartrate resistant acid phosphatase. Creatine kinase-BB in mammalian osteopetrosis is related to osteoclastic number and size, where it probably reflects the differentiation and maturation of inactive bone resorbing cells. The isoenzyme does not seem to be a valuable screening marker for osteopetrosis.


Subject(s)
Creatine Kinase/genetics , Osteopetrosis/enzymology , Osteopetrosis/genetics , Adult , Animals , Female , Humans , Isoenzymes , Male , Mice , Middle Aged , Mutation , Rats
18.
Int J Dev Biol ; 44(3): 309-16, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10853827

ABSTRACT

The pacemaker of endochondral bone growth is cell division and hypertrophy of chondrocytes. The developmental stages of chondrocytes, characterized by the expression of collagen types II and X, are arranged in arrays across the growth zone. Mutations in collagen II and X genes as well as the absence of their gene products lead to different, altered patterns of chondrocyte stages which remain aligned across the growth plate (GP). Here we analyze GP of rats bearing the mutation toothless (tl) which, apart from bone defects, develop a progressive, severe chondrodystrophy during postnatal weeks 3 to 6. Mutant GP exhibited disorganized, non-aligned chondrocytes and mineralized metaphyseal bone but without cartilage mineralization or cartilaginous extensions into the metaphysis. Expression of mRNA coding for collagen types II (Col II) and X (Col X) was examined in the tibial GP by in situ hybridization. Mutant rats at 2 weeks exhibited Col II RNA expression and some hypertrophied chondrocytes (HC) but no Col X RNA was detected. By 3rd week, HC had largely disappeared from the central part of the mutant GP and Col II RNA expression was present but weak and in 2 separate bands. Peripherally the GP contained HC but without Col X RNA expression. This abnormal pattern was exacerbated by the fourth week. Bone mineralized but cartilage in the GP did not. These data suggest that the tl mutation involves a regulatory function for chondrocyte maturation, including Col X RNA synthesis and mineralization, and that the GP abnormalities are related to the Col X deficiency. The differences in patterning in the tl rat GP compared to direct Col X mutations may be explained by compensatory effects.


Subject(s)
Bone and Bones/embryology , Chondrocytes/metabolism , Collagen/biosynthesis , Osteopetrosis/metabolism , Animals , Coloring Agents/pharmacology , Disease Models, Animal , Gene Expression , In Situ Hybridization , Rats , Rats, Mutant Strains , Tibia/metabolism , Tibia/pathology , Tolonium Chloride/pharmacology
19.
Int J Dev Biol ; 44(2): 201-7, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10794078

ABSTRACT

We have shown that in the osteopetrotic rat mutation toothless (tl) osteoblasts are absent from older bone surfaces in mutants and that mutant osteoblasts in vivo lack the prominent stress fiber bundles polarized along bone surfaces in osteoblasts from normal littermates. Our recent data demonstrate that in normal osteoblasts in vitro beta- and gamma-actin mRNAs have different, characteristic intracellular distributions and that tl (mutant) osteoblasts fail to differentially sort these mRNAs. Because bone resorption and formation are highly interdependent and injections of CSF-1, a growth factor, increase bone resorption and growth in tl rats, we examined the effects of CSF-1 treatment on osteoblast survival and ultrastructure in vivo and ability to sort actin mRNAs in vitro. Neonatal CSF-1 treatment of mutants restores osteoblasts on older bone surfaces, normalizes the intracellular distribution of stress fibers in osteoblasts in vivo and promotes normal sorting of beta-actin mRNA in mutant osteoblasts in vitro without normalizing gamma-actin distribution. These data suggest the beta- and gamma-actin mRNAs in osteoblasts are sorted by different mechanisms and that the differential sorting of beta-actin mRNA is related to the characteristic polarization of stress fibers in osteoblasts and their survival on bone surfaces. This experimental system can be used to explore the relationships and regulation of these aspects of cell and tissue biology.


Subject(s)
Actins/metabolism , Macrophage Colony-Stimulating Factor/physiology , Mutation , Osteoblasts/metabolism , RNA, Messenger/metabolism , Actins/chemistry , Animals , Bone and Bones/metabolism , Cell Adhesion , Cell Survival , Cells, Cultured , Osteopetrosis/genetics , Phenotype , Protein Isoforms , Rats , Rats, Mutant Strains , Signal Transduction
20.
Bone ; 26(2): 137-45, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10678408

ABSTRACT

The cytokines interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and IL-6 induce osteoclast formation and may contribute to the development of postmenopausal osteoporosis. Cross-sectional studies have suggested that both IL-1 and IL-1ra secretion increase on estrogen withdrawal, and that postmenopausal osteoporosis is associated with an inadequate increase in monocyte IL-1ra secretion with age. We measured cytokine mRNA (IL-1beta, IL-1ra, IL-6, and TNF-alpha) directly in bone biopsies from early postmenopausal women to determine if a lower compensatory increase in IL-1ra mRNA could be demonstrated in women with rapid bone loss after the menopause. Biopsies were obtained from 23 early postmenopausal women (mean age 53.9 years) who participated in a randomized study of hormone replacement therapy (HRT) and risk factors for osteoporosis. Bone mineral density was assessed by duel energy X-ray absorptiometry at 0, 1, 2, and 5 years. Women in the control group were recruited to the biopsy study based on their observed rate of bone loss (upper or lower tertile). Consent was also obtained from 11 participants receiving HRT. Biopsies were taken at 2 years, frozen in nitrogen, and homogenized. Cytokine mRNA was measured by competitive reverse transcriptase polymerase chain reaction. The IL-1ra/IL-1beta mRNA slope for the slow-loss group was steeper (deltaF = 23.3, p < 0.01) than that observed in the fast-loss group, indicating that slower bone loss was associated with higher IL-1ra mRNA levels relative to IL-1beta. During HRT, the IL-1beta mRNA level was inversely correlated with serum estradiol (log r2 = 0.77, p < 0.01), and women with a serum estradiol below 200 pmol/L during HRT had IL-1beta, mRNA levels identical to the control group. In contrast, IL-1ra mRNA was independent of serum estradiol. Histomorphometric analysis revealed weak correlations between IL-1beta mRNA and activation frequency (r2 = 0.26, p = 0.06) and between IL-1ra and volume referent bone resorption rate (r2 = 0.19, p = 0.11). TNF-alpha was not associated with the bone loss rates or with serum estradiol, and only three samples were positive for IL-6 mRNA. The findings support the hypothesis that IL-1beta production within bone increases with declining estrogen levels, and that an increase in II-1ra protects against accelerated bone loss.


Subject(s)
Cytokines/genetics , Ilium/immunology , Ilium/metabolism , Menopause/immunology , Menopause/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Base Sequence , Bone Density , DNA Primers/genetics , Estradiol/blood , Estrogen Replacement Therapy , Female , Humans , Interleukin 1 Receptor Antagonist Protein , Interleukin-1/genetics , Interleukin-6/genetics , Longitudinal Studies , Middle Aged , Osteoporosis, Postmenopausal/immunology , Osteoporosis, Postmenopausal/metabolism , Osteoporosis, Postmenopausal/prevention & control , Sialoglycoproteins/genetics , Tumor Necrosis Factor-alpha/genetics
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