bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulsed electromagnetic fields affect phenotype and connexin 43 protein expression in MLO‐Y4 osteocyte‐like cells and ROS 17/2.8 osteoblast‐like cells
Authors: Lohmann C. H. , Schwartz Z. , Liu Y. , Li Z. , Simon B. J. , Sylvia V. L. , Dean D. D. , Bonewald L. F. , Donahue H. J. , Boyan B. D. 
Published: February 2003

AbstractOsteocytes, the predominant cells in bone, are postulated to be responsible for sensing mechanical and electrical stimuli, transducing signals via gap junctions. Osteocytes respond to induced shear by increasing connexin 43 (Cx43) levels, suggesting that they might be sensitive to physical stimuli like low‐frequency electromagnetic fields (EMF). Immature osteoblasts exhibit decreased intercellular communication in response to EMF but no change in Cx43. Here, we examined long term effects of pulsed EMF (PEMF) on MLO‐Y4 osteocyte‐like cells and ROS 17/2.8 osteoblast‐like cells. In MLO‐Y4 cell cultures, PEMF for 8 h/day for one, two or four days increased alkaline phosphatase activity but had no effect on cell number or osteocalcin. Transforming growth factor beta‐1 (TGF‐β1) and prostaglandin E2 were increased, and NO2‐ was altered. PEMFs effect on TGF‐β1 was via a prostaglandin‐dependent mechanism involving Cox‐1 but not Cox‐2. In ROS 17/2.8 cells, PEMF for 24, 48 or 72 h did not affect cell number, osteocalcin mRNA or osteocalcin protein. PEMF reduced Cx43 protein in both cells. Longer exposures decreased Cx43 mRNA. This indicates that cells in the osteoblast lineage, including well‐differentiated osteoblast‐like ROS 17/2.8 cells and terminally differentiated osteocyte‐like MLO‐Y4 cells, respond to PEMF with changes in local factor production and reduced Cx43, suggesting decreased gap junctional signaling.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Autologous osteoblasts enhance osseointegration of porous titanium implants
Authors: Frosch K.‐H. , Sondergeld I. , Dresing K. , Rudy T. , Lohmann C. H. , Rabba J. , Schild D. , Breme J. , Stuermer K. M. 
Published: February 2003

AbstractThe goal of this study was to assess the osseointegration of porous titanium implants by means of coating with autologous osteoblasts.Titanium implants (8 × 5 × 4 mm) having drill channels with diameters of 400, 500, and 600 μm were coated with autologous osteoblasts obtained from spongiosa chips. The implants were inserted into the distal femora of 17 adult Chinchilla Bastard rabbits (group I). Uncoated implants were inserted as controls in the contralateral femur (group II). The animals were sacrificed after 5, 11, and 42 days. Intravital fluorochrome labeling and microradiography were used for the assessment of bone ingrowth into the titanium channels.In both groups, no bone tissue was formed in the channels up to day 5. On day 11, group I exhibited significantly more (p<0.05) bone tissue (19.8 ± 14.0% vs. 5.8 ± 9.1%) with greater bone‐implant contact (13.3 ± 15.1% vs. 5.7 ± 5.3%, p<0.05) at the channel mouths than group II. Bone tissue was formed mainly between day 15 and 30 in group I, in group II between day 25 and 40.Six weeks after implantation, bone tissue filled on an average 68.8 ± 15.1% of the mouths of the drill channels in implants in group I, the filling for group II was 49.8 ± 18.1% (p<0.05). The average bone‐implant contact at the channel mouths after six weeks was 56.5 ± 13.5% in group I, 40.2 ± 21.9% in group II (p<0.05). 600‐μm channels showed at this time point the best osseous integration (p<0.05).Coating with autologous osteoblasts accelerates and enhances the osseointegration of titanium implants and could be a successful biotechnology for future clinical applications.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Localization of insulin‐like growth factor binding protein‐2 in chondrocytes of bovine articular cartilage
Authors: Morales Teresa I. , Hunziker Ernst B. 
Published: February 2003

AbstractPurpose: Previous work indicated that transforming growth factor (TGF‐β) treatment of bovine articular cartilage resulted in an accumulation of insulin‐like growth factor binding protein‐2 (IGF‐BP‐2). The purpose of the work presented in this paper was to define the localization of the IGF‐BP‐2 in freshly excised articular cartilage and in slices cultured in the presence and absence of TGF‐β.Method: Newborn calf articular cartilage was dissected and immediately fixed or maintained in organ culture for five days under basal conditions (media without added serum or growth factors) or with basal media containing 15 ng/ml of TGF‐β1. Frozen or paraffin embedded sections were prepared, and immunohistochemistry using anti‐IGF‐BP‐2 performed.Results: The paraffin sections provided the best preservation of morphology and consistency of immunohistochemical staining patterns. In fresh cartilage slices, IGF‐BP‐2 was associated with most of the chondrocytes. The basal cultured cartilage showed positive immunostaining in some areas, but not others: the most consistently stained area was the upper radial zone. In all cases where a positive reaction was observed, it was associated mostly with chondrocytes. On the other hand, all the TGF‐β treated samples that were examined in this study were evenly stained, and most chondrocytes were positive in all areas from superficial to deep zones, thus closely resembling the pattern of fresh tissue.Conclusions: It is concluded that IGF‐BP‐2 is closely cell associated in bovine articular cartilage. Following culture of cartilage slices, TGF‐β increases the number of cells with positive immunostaining. These data help to support the postulate that TGF‐β exerts at least some of its actions in articular cartilage via cross‐talk mechanisms involving the IGF‐BP‐2 system.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Neurohistological examination of the inferior glenohumeral ligament of the shoulder
Authors: Steinbeck Jörn , Brüntrup Jens , Greshake Oliver , Pötzl Wolfgang , Filler Timm , Liljenqvist Ulf 
Published: February 2003

AbstractThe neural histology of the anterior band of the inferior glenohumeral ligament (IGHL) was studied in 11 fresh shoulder specimen using a special silver impregnation technique. Between the collagen fibers small myelinated and unmyelinated dendrites could be detected. The appearance of neurovascular structures in the adjacent synovial layer clearly exceeded the typical supply to soft tissues. Analysing about 11,000 sections Ruffini mechanoreceptors that are known to be slow adapting were found on the humeral insertion of the band. The sections containing these neural end organs were identified by means of transillumination and reflection‐contrast microscopy and reconstructed using three‐dimensional image processing. The presence of neural structures including Ruffini corpuscles in these most important passive stabilizers of the shoulder joint shows that these ligaments function also as an active safety device. There slow adaption is a prerequisite for muscular reflexes counteracting the tensile stresses to which the passive stabilizing structures of the shoulder are exposed. A disruption of the continuity of these structures by mechanical forces or surgery can reduce the biofeedback and proprioceptive quality and thus lead to a decrease of shoulder function and/or stability. These observations should be taken into account when planning surgical interventions involving the IGHL. Procedures like capsule shifts or plications may affect mechanoreceptor orientation and concentrations, thereby affecting the interaction between these structures and the synergistic muscles. When possible, these intervention should avoid receptor‐dense regions while attempting to restore normal anatomical orientation and tissue tension.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Determination of cortical bone porosity and pore size distribution using a low field pulsed NMR approach
Authors: Wang Xiaodu , Ni Qingwen 
Published: February 2003

AbstractThe objective of this study was first to prove the concept of a low field pulsed nuclear magnetic resonance (NMR) process for assessing the cortical porosity and pore size distribution of human bone in vitro, and then to apply the technique to detect age‐related changes of bone in these parameters. The Carr‐Purcell‐Meiboom‐Gill NMR spin echo train method is used to determine the porosity, and an inversion NMR spin‐spin relaxation (T2) spectrum is used to assess the pore size distribution in cortical bone. Using these techniques, cortical porosity and pore size distribution of 19 specimens of human cadaveric bone, ranging from 16 to 89 years of age, were assessed. The NMR results were compared with the histomorphometric data of the same bone samples to verify the efficacy of the NMR approach. Moreover, a coefficient (surface relaxivity) relating the pore size to the T2 relaxation time was determined empirically for the Haversian canals and the osteocytic lacunae. The results of this study demonstrate that the in vitro NMR approach using T2 relaxation techniques can directly assess the porosity and pore size distribution (Haversian canals and osteocytic lacunae) in human cortical bone. In addition, this study indicates that the age‐related changes in cortical porosity relate predominantly to Haversian canals, whereas the porosity of osteocytic lacunae appears to be independent of age.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Induction of CD‐RAP mRNA during periosteal chondrogenesis
Authors: Sanyal Arunik , Clemens Victoria , Fitzsimmons James S. , Reinholz Gregory G. , Sarkar Gobinda , Mukherjee Nilay , O'Driscoll Shawn W. 
Published: February 2003

AbstractInduction of chondrogenesis and maintenance of the chondrocyte phenotype are critical events for autologous periosteal transplantation, which is a viable approach for cartilage repair. Cartilage‐derived retinoic acid‐sensitive protein (CD‐RAP) is a recently discovered protein that is mainly produced in cartilage. During development, CD‐RAP expression starts at the beginning of chondrogenesis and continues throughout cartilage maturation. In order to investigate the involvement of CD‐RAP during periosteal chondrogenesis we have determined the nucleotide sequence of the rabbit CD‐RAP mRNA and utilized this information to evaluate the temporal and spatial expression pattern of CD‐RAP at the mRNA level during chondrogenesis. When the periosteal explants were cultured under chondrogenic conditions, the expression of CD‐RAP was induced, as shown by a 40‐fold increase in CD‐RAP mRNA between days 7 and 10. The temporal expression pattern of CD‐RAP closely mimicked that of collagen type IIB mRNA. Also, the CD‐RAP mRNA was localized to the matrix forming chondrocytes in the cambium layer of the periosteum by in situ hybridization as indicated by colocalization with collagen type II mRNA and positive safranin O staining. These data suggest a regulatory role of CD‐RAP in periosteal chondrogenesis, which is potentially important for both cartilage repair and fracture healing via callus formation.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Effects of locally applied vascular endothelial growth factor (VEGF) and VEGF‐inhibitor to the rabbit tibia during distraction osteogenesis
Authors: Eckardt Henrik , Bundgaard Kristian G. , Christensen Knud S. , Lind Martin , Hansen Ebbe S. , Hvid Ivan 
Published: February 2003

AbstractIntroduction: Therapeutic angiogenesis, a novel concept in tissue engineering, is neo‐formation of blood vessels in a tissue upon delivery of an angiogenic growth factor to the tissue. We hypothesised that therapeutic angiogenesis could enhance bone formation and challenged the hypothesis in an experimental model of distraction osteogenesis.Methods: Rabbits, divided into three equal groups of 12, had their right tibia lengthened by distraction osteogenesis. A miniosmotic pump delivered to the osteotomy gap either recombinant human vascular endothelial growth factor (VEGF), VEGF‐inhibitor, or vehicle alone during the latency and distraction phase. After consolidation, we assessed bone blood flow by radioactive microsphere entrapment, measured torsional stiffness and bone mineral content, and did histomorphometry.Results: VEGF and VEGF‐inhibitor treatment failed to influence bone blood flow, torsional stiffness, bone mineral content and histomorphometric indices of the bone regenerate. However, VEGF treatment increased the blood flow in bone of the distracted limb and VEGF‐inhibitor treatment decreased bone blood flow.Conclusion: The regenerate was unresponsive to VEGF and VEGF‐inhibitor treatment in contrast to the neighbouring bone, which implies different biological properties of the vasculature in native and regenerating bone. VEGF is not recommended for enhancement of bone formation in this setting.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The relationship between knee strength and functional stability before and after anterior cruciate ligament reconstruction
Authors: Keays S. L. , Bullock‐Saxton J. E. , Newcombe P. , Keays A. C. 
Published: February 2003

AbstractFunctional stability of the knee is dependent on an intact ligamentous system and the timely and efficient contraction of supporting musculature. The aim of this study was to assess the relationship between muscle strength and functional stability in 31 patients pre‐ and post‐operatively, following a unilateral anterior cruciate ligament rupture. All subjects underwent reconstructive surgery using semitendonosis and gracilis tendons. Isokinetic strength assessment of quadriceps and hamstring muscles was performed at a rate of movement of 60°/s and 120°/s. Functional stability was determined by performance during five functional stability tests that included the shuttle run, side step, carioca, single and triple hop tests. Pearson's correlation coefficient statistics were applied to pre‐operative and post‐operative data respectively. These analyses demonstrated a significant positive correlation between quadriceps strength indices at both testing speeds and the two hop tests pre‐operatively (p's<0.007) and between quadriceps strength indices at both speeds and all five functional tests post‐operatively (p's<0.01). Assessed using Steiger's formula, there was a significant increase in the correlation between quadriceps strength indices and three functional tests post‐operatively compared to pre‐operatively (p<0.05). No significant correlation between hamstring strength indices and functional scores existed pre‐ or post‐operatively. This study has shown a significant correlation exists between quadriceps strength indices and functional stability both before and after surgery, this relationship does not reach significance between hamstring strength indices and functional stability.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Characterization of proliferation and differentiation of EGF‐responsive striatal and septal precursor cells
Authors: Castillo Lazara , Martı́nez Lisis , Grygar Elizabeth , Hutter‐Paier Birgit 
Published: February 2003

AbstractThe epigenetic manipulation of precursors may provide data to elucidate the potential interactions among these cells in different brain regions. However, the response to epigenetic signals is modulated by the environment in which the cells are manipulated. Therefore, data regarding the action of a particular factor must be considered in the light of a specific system. To compare septal and striatal precursors, we have tested the effect of nerve growth factor (NGF) on the proliferation and neuronal differentiation of epidermal growth factor (EGF)‐responsive cells from these brain regions. Precursors were cultivated as ‘neuropheres’ in serum free medium (SFM) to which NGF was added. NGF did not support the proliferation of EGF‐generated precursors so that no differences in the cell magnitude with respect to control cultures were observed. Differentiation of precursors in SFM plus 1% fetal bovine serum (FBS) on poly‐d‐lysine showed that the neuron number was increased two‐fold in septal cultures treated with NGF but not in those from striatum. A quantitative evaluation of the soma surface and the number of primary neurites showed differences between both populations of precursor‐generated neurons. In addition, we also observed no influence of NGF on these parameters of cellular morphology. Thus, taken together these results seem to indicate that at this developmental stage in which these populations of precursors were isolated, heterogeneities exist between them, which is probably related to their origin and/or functional roles in vivo.
GABAAβ2–3 immunoreactive cells in the developing chick retina
Authors: Barros Pedro Henrique Oliveira Cavalcanti , Calaza Karin da Costa , Gardino Patrı́cia Franca 
Published: February 2003

AbstractGama‐aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system (CNS). It has been shown that GABA is an important factor for CNS maturation and that its functions are mainly mediated by GABAA receptors. Thus, in order to fully comprehend the role of GABA during development, it is essential to establish the developmental features of the catalytic subunits (β) of GABAA receptor. Here, we determine the ontogenesis and neurogenesis of cells expressing β2–3 subunits of GABAA receptor (GABAAβ2–3) in the chick retina. In the ontogenetic experiments, only the immunohistochemistry for GABAAβ2–3 approach was employed. For neurogenesis a double‐labeling method (autoradiography and immunohistochemistry) was applied. [H3]‐thymidine was injected into eggs (2–11 days) and the embryos were sacrificed at embryonic day 19 (E19). GABAAβ2–3 immunohistochemistry was processed and then autoradiography was performed. We used a cumulative counting method to quantify the autoradiographic grains. The ontogenesis study revealed that at E9, GABAAβ2–3 immunoreactivity was restricted to the inner plexiform layer and the first cell bodies immunoreactive to GABAAβ2–3 were seen at E14. Thereafter, the number of cell bodies and the intensity of GABAAβ2–3 immunoreactivity increased until the adult pattern was established. The neurogenesis study showed that cells that will express GABAAβ2–3 were generated between E6 and E9. In addition, from E7 to E9 the rate of neurogenesis of GABAAβ2–3 immunoreactive cells quickly increases. Therefore, the detection of GABAAβ2–3 occurred only after the end of generation period of this cell population.
Corn feeding during development induces changes in the number of serotonergic neurons in the raphe nuclei
Authors: Orozco‐Suárez Sandra , Del Angel Alma Rosa , Beas‐Zárate Carlos , Manjarrrez Gabriel , Feria‐Velasco Alfredo 
Published: February 2003

AbstractSerotonin (5‐HT) plays a trophic role during brain development; chronic changes in cerebral concentration of this neurotransmitter during the critical stage of development can produce severe damage in the formation of the neural circuits. For the present work a hypoproteic (HYP) diet based on corn (CORN) meal which is deficient in tryptophan (TRY) was given to rats before and during pregnancy, which continued to the offspring until they reached 60 days of age. An isocaloric but hypoproteic diet containing normal amount of TRY, and normal chow (Ch) Purina were given with the same scheme to two groups of rats considered as controls. 5‐HT immunohistochemistry was revealed by avidin–biotin complex (ABC) method to quantify serotonergic nerve cells in the nine raphe nuclei. The number of cells immunoreactive to 5‐HT immunoreactive (5‐HTir) were quantified by means of stereological analysis. Results demonstrated a significant variation in 5‐HT expression in the raphe nuclei. Thus, a significant reduction in the number of 5‐HTir cells in the rostral raphe nuclei was seen at all ages studied in the animals fed the corn diet, compared to data obtained from the control groups. This decrease was more evident between the postnatal ages of 30 and 60 days. It is concluded that the variations in the available TRY affect the brain cells producing 5‐HT and the innervation of their target areas.
NEURORECEPTOR mRNA EXPRESSION IN THE RAT MESENTERIC ARTERY DEVELOPS INDEPENDENTLY OF INNERVATION
Authors: Phillips Jacqueline K. , Hill Caryl E. 
Published: February 2003

AbstractStudies in autonomic targets have shown that nerves may be required for the development and maintenance of postsynaptic receptor populations. We have examined this relationship in the rat mesenteric artery, assessing mRNA expression levels for a range of neuroreceptors after neonatal sympathectomy, using 6‐hydroxydopamine or antisera directed against nerve growth factor, and sensory denervation, using capsaicin. Total RNA was extracted from 28 day old rats and reverse transcription‐polymerase chain reaction was performed, using primers specific for the α1(A,B,D)‐ and α2(A,B,C)‐adrenergic, neurokinin (NK1–NK3), muscarinic (M1–M5) and P2X purinergic (P2X1–7) receptor families. Results showed no decreases in mRNA expression of any of the specific receptor subtypes after either sympathetic or sensory denervation. Small increases in mRNA expression were detected following sensory denervation for some of the receptor subtypes. We conclude that neither sympathetic nor sensory nerves are mandatory for the expression of mRNA of a range of neuroreceptors in the mesenteric vascular bed of the rat.
Fetal human cortical neurons grown in culture: morphological differentiation, biochemical correlates and development of electrical activity
Authors: Kerkovich Danielle M. , Sapp Douglas , Weidenheim Karen , Brosnan Celia F. , Pfeiffer Steven E. , Yeh Hermes H. , Busciglio Jorge 
Published: February 2003

AbstractCultured fetal human cortical neurons derived from second trimester human fetal cortex were analyzed with regard to their morphological differentiation and expression of cell‐specific markers. The culture method was adapted from standardized protocols originally developed for the isolation and culture of rodent oligodendrocytes and astrocytes. This technique takes advantage of the different adhesive properties and stratification of central nervous system cells in vitro. Under these culture conditions fetal human cortical neurons underwent morphological differentiation, expressed neuron‐specific markers and voltage‐ and ligand‐gated ion channels. Highly enriched cultures of microglia and astrocytes generated from the same starting material also expressed cell‐type specific markers. These cultures serve as a valuable tool for the establishment of normative data and as experimental models for neurodevelopmental and neurodegenerative studies.