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Abstract
Glycosylation using Tf2NH or Tf2NTMS as the catalysts and a trichloroacetimidate donor gives glycosides with inverted anomeric stereochemistry.
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Affiliation(s)
- K. Kowalska
- Department of Chemistry
- University of Copenhagen
- Universitetsparken 5
- DK-2100 Copenhagen
- Denmark
| | - C. M. Pedersen
- Department of Chemistry
- University of Copenhagen
- Universitetsparken 5
- DK-2100 Copenhagen
- Denmark
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2
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Birkbak J, Stuart EA, Lind BD, Qin P, Stenager E, Larsen KJ, Wang AG, Nielsen AC, Pedersen CM, Winsløv JH, Langhoff C, Mühlmann C, Nordentoft M, Erlangsen A. Psychosocial therapy and causes of death after deliberate self-harm: a register-based, nationwide multicentre study using propensity score matching. Psychol Med 2016; 46:3419-3427. [PMID: 27654845 DOI: 10.1017/s0033291716001872] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Psychosocial therapy after deliberate self-harm might be associated with reduced risk of specific causes of death. METHOD In this matched cohort study, we included patients, who after an episode of deliberate self-harm received psychosocial therapy at a Suicide Prevention Clinic in Denmark between 1992 and 2010. We used propensity score matching in a 1:3 ratio to select a comparison group from 59 046 individuals who received standard care. National Danish registers supplied data on specific causes of death over a 20-year follow-up period. RESULTS At the end of follow-up, 391 (6.9%) of 5678 patients in the psychosocial therapy group had died, compared with 1736 (10.2%) of 17 034 patients in the matched comparison group. Lower odds ratios of dying by mental or behavioural disorders [0.54, 95% confidence interval (CI) 0.37-0.79], alcohol-related causes (0.63, 95% CI 0.50-0.80) and other diseases and medical conditions (0.61, 95% CI 0.49-0.77) were noted in the psychosocial therapy group. Also, we found a reduced risk of dying by suicide as well as other external causes, however, not by neoplasms and circulatory system diseases. Numbers needed to treat were 212.9 (95% CI 139.5-448.4) for mental or behavioural disorders as a cause of death, 111.1 (95% CI 79.2-210.5) for alcohol-related causes and 96.8 (95% CI 69.1-161.8) for other diseases and medical conditions. CONCLUSIONS Our findings indicate that psychosocial therapy after deliberate self-harm might reduce long-term risk of death from select medical conditions and external causes. These promising results should be tested in a randomized design.
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Affiliation(s)
- J Birkbak
- Research Unit,Mental Health Centre Copenhagen,University of Copenhagen,Capital Region of Denmark,Denmark
| | - E A Stuart
- Department of Mental Health,Johns Hopkins Bloomberg School of Public Health,Baltimore, MD,USA
| | - B D Lind
- Department of Psychiatry,Clinic of Suicide Prevention and Treatment for Adults,Region of Southern Denmark,Denmark
| | - P Qin
- National Centre for Suicide Research and Prevention, University of Oslo,Oslo,Norway
| | - E Stenager
- Psychiatric Research Unit,Aabenraa,University of Southern Denmark,Odense,Denmark
| | - K J Larsen
- Department of Child and Adolescent Psychiatry,Clinic of Suicide Prevention and Treatment for Children and Adolescents,Region of Southern Denmark,Denmark
| | - A G Wang
- Competence Centre for Suicide Prevention,Amager,Capital Region of Denmark,Denmark
| | - A C Nielsen
- Competence Centre for Suicide Prevention,Copenhagen,Capital Region of Denmark,Denmark
| | - C M Pedersen
- Clinic for Suicide Prevention, Aarhus University Hospital Risskov,Aarhus,Central Denmark Region,Denmark
| | - J-H Winsløv
- Unit for Suicide Prevention,Aalborg University Hospital,North Denmark Region,Denmark
| | - C Langhoff
- Clinic for Suicide Prevention,Herning,Central Denmark Region,Denmark
| | - C Mühlmann
- Research Unit,Mental Health Centre Copenhagen,University of Copenhagen,Capital Region of Denmark,Denmark
| | - M Nordentoft
- Research Unit,Mental Health Centre Copenhagen,University of Copenhagen,Capital Region of Denmark,Denmark
| | - A Erlangsen
- Research Unit,Mental Health Centre Copenhagen,University of Copenhagen,Capital Region of Denmark,Denmark
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3
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Pedersen CM, Schmidt MR, Barnes G, Botker HE, Kharbanda RK, Newby DE, Cruden NL. Bradykinin does not mediate remote ischaemic preconditioning or ischaemia-reperfusion injury in vivo in man. Heart 2011; 97:1857-61. [DOI: 10.1136/heartjnl-2011-300323] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Pedersen CM, Cruden NL, Schmidt MR, Lau C, Bøtker HE, Kharbanda RK, Newby DE. Remote ischemic preconditioning prevents systemic platelet activation associated with ischemia-reperfusion injury in humans. J Thromb Haemost 2011; 9:404-7. [PMID: 21083644 DOI: 10.1111/j.1538-7836.2010.04142.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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5
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Ejsing L, Smistrup K, Pedersen CM, Mortensen NA, Bruus H. Frequency response in surface-potential driven electrohydrodynamics. Phys Rev E Stat Nonlin Soft Matter Phys 2006; 73:037302. [PMID: 16605705 DOI: 10.1103/physreve.73.037302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Indexed: 05/08/2023]
Abstract
Using a Fourier approach we offer a general solution to calculations of slip velocity within the circuit description of the electrohydrodynamics in a binary electrolyte confined by a plane surface with a modulated surface potential. We consider the case with a spatially constant intrinsic surface capacitance where the net flow rate is, in general, zero while harmonic rolls as well as time-averaged vortexlike components may exist depending on the spatial symmetry and extension of the surface potential. In general, the system displays a resonance behavior at a frequency corresponding to the inverse time of the system. Different surface potentials share the common feature that the resonance frequency is inversely proportional to the characteristic length scale of the surface potential. For the asymptotic frequency dependence above resonance we find a omega(-2) power law for surface potentials with either an even or an odd symmetry. Below resonance we also find a power law omega(alpha) with alpha being positive and dependent of the properties of the surface potential. Comparing a tanh potential and a sech potential we qualitatively find the same slip velocity, but for the below-resonance frequency response the two potentials display different power-law asymptotics with alpha=1 and alpha approximately 2, respectively.
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Affiliation(s)
- L Ejsing
- MIC-Department of Micro and Nanotechnology, Technical University of Denmark, NanoDTU Bldg. 345 East, DK-2800 Kongens Lyngby, Denmark
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6
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Hansen TG, Sprogøe-Jakobsen U, Pedersen CM, Olsen KS, Kristensen SR. Haemolysis following rapid experimental red blood cell transfusion--an evaluation of two infusion pumps. Acta Anaesthesiol Scand 1998; 42:57-62. [PMID: 9527746 DOI: 10.1111/j.1399-6576.1998.tb05081.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND The vast majority of infusion pumps used for rapid transfusion of large amounts of blood have never been properly examined regarding their influence on the quality of the red blood cells (RBCs) infused. In this study, we evaluated the effect of two different infusion pumps on the degree of RBC destruction following rapid experimental blood transfusion. METHODS Divided into 2 groups according to age, 30 u of SAGM RBCs were infused through an experimental transfusion model by either a manual roller pump (MRP) or a pressure infusor pump (PIP). Fresh (i.e stored for 8-11 d) RBCs, 20 u, and 10 u of older (i.e. stored for 25-33 d) RBCs were randomly allocated to infusion with either of the two pumps. The rate of infusion was as fast as possible with the MRP, and with the PIP adjusted with an external applied pressure of 300 mm Hg. RBC samples collected before and after infusion were analyzed for total haemoglobin, free haemoglobin, haematocrit, total free potassium, lactate dehydrogenase (LDH) and the percentage of haemolysis. The time spent for each transfusion was measured by a stop watch. RESULTS Following infusion, a marginal increase (i.e. considerably below 0.8%) in the percentage of haemolysis and LDH content was seen with both pumps. This increase was only statistically significant when RBCs stored for 8-11 d were used (P = 0.002 for both parameters). Irrespective of the age of the RBCs, no differences between the two pumps could be detected. Compared to the PIP, infusion with the MRP could be accomplished significantly faster, i.e. median 5.9 ml/s (5.2-6.4 ml/s) versus 2.9 ml/s (2.5-3.2 ml/s), (P < 0.0001). CONCLUSIONS Both the pumps used in this study are safe alternatives for rapid transfusion of RBCs; however, with MRP this can be accomplished approximately twice as fast as with the PIP.
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Affiliation(s)
- T G Hansen
- Department of Anaesthesia and Intensive Care, Odense University Hospital, Odense C, Denmark
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7
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Pedersen CM, Hansen TG, Henneberg SW. [Persistent pulmonary hypertension in newborn infants]. Ugeskr Laeger 1997; 159:4377-82. [PMID: 9235733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
On the basis of a review of the literature, a survey is presented concerning persistent pulmonary hypertension of the newborn. In this article the authors focus on the pathophysiology, diagnostic criteria and treatment, including mechanical ventilation, pharmacological vasodilation and extracorporal membrane oxygenation. Particular emphasis is placed on the treatment of the condition with inhaled nitric oxide. Nitric oxide is a selective pulmonary vasodilator and able to improve ventilation/ perfusion mismatching in cases where there is an affection of the pulmonary parenchyma. Data from randomized trials with close long-term follow-up is necessary before routine nitrogen oxide treatment can be recommended.
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Affiliation(s)
- C M Pedersen
- Odense Universitetshospital, anaestesi- og intensivafdeling V
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8
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Abstract
The quality of the glenoid bone is important to a successful total shoulder replacement. Finite element models have been used to model the response of the glenoid bone to an implanted prosthesis. Because very little is known about the bone strength and the material properties at the glenoid, these models were all based on assumptions that the material properties of the glenoid were similar to those of the tibial plateau. The osteopenetrometer was used to assess the topographic strength distribution at the glenoid. Strength at the proximal subchondral level of the glenoid averaged 66.9 MPa. Higher peak values were measured posteriorly, superiorly, and anteriorly to the area of maximum concavity of the glenoid joint surface known as the bare area. One millimeter underneath the subchondral plate, average strength decreased by 25%, and at the 2 mm level strength decreased by 70%. The contribution of the cortical bone to the total glenoid strength was assessed by compression tests of pristine and cancellous-free glenoid specimens. Strength decreased by an average of 31% after the cancellous bone was removed. The material properties of the glenoid cancellous bone were determined by axial compression tests of bone specimens harvested from the central part of the glenoid subchondral area. The elastic modulus varied from approximately 100 MPa at the glenoid bare area to 400 MPa at the superior part of the glenoid. With the elastic constants used a predictor of the mechanical anisotropy, the average anisotropy ratio was 5.2, indicating strong anisotropy. The apparent density was an average 0.35 gr. cm-3, and the Poisson ratio averaged 0.263. According to our findings the anisotropy of the glenoid cancellous bone, details concerning the strength distribution, and the load-bearing function of the cortical shell should be considered in future finite element models of the glenoid.
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Affiliation(s)
- L H Frich
- Biomechanics Laboratory, University Hospital of Aarhus, Denmark
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9
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Hansen TG, Pedersen CM, Henneberg SW. [Sedation and analgesia in ventilator-treated children]. Ugeskr Laeger 1996; 159:31-6. [PMID: 9012071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ventilator-treated children often require sedation in order to facilitate the ventilation. Sedatives alone or in combination with analgesics are commonly used for this purpose. In some cases, however, the addition of a neuromuscular blocking agent (NMB) may be necessary. In this article a survey is presented regarding both pharmacological and non-pharmacological means of improving the ventilator treatment in ventilated children. The most commonly employed sedatives, opioids and NMB's are discussed. The authors stress that whichever drug is used, it should be administered to the children guided by its effects rather than by a rigid scheme. In that respect monitoring of the treatment is important.
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Affiliation(s)
- T G Hansen
- Odense Universitetshospital, anaestesiologisk intensiv afdeling V
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10
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Hansen TG, Pedersen CM, Lybecker H. [Severe bronchospasm in a 1-year old child treated with halothane]. Ugeskr Laeger 1994; 156:58-9. [PMID: 8291159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A case of severe bronchospasm in a one-year old mechanically ventilated girl which in spite of maximal conventional bronchodilatory treatment only responded to halothane inhalation is presented. The benefits and limitations of this therapy are discussed.
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Affiliation(s)
- T G Hansen
- Odense Sygehus, anaestesi- og intensivafdeling V
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11
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Pedersen CM, Stjernholm PH, Hansen TG, Lybecker H. [Bronchodilating inhalation anesthetics in bronchial asthma and status asthmaticus]. Ugeskr Laeger 1994; 156:25-30. [PMID: 8291152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
On the basis of a review of the literature, a survey is presented concerning the use of halogenated inhalational anaesthetics (halothane, enflurane, isoflurane) in anaesthesia of asthmatic patients and in intensive care units in the treatment of status asthmaticus refractory to maximal standard therapy. Particular emphasis is placed on the bronchospasmolytic, cardiovascular and organotoxic effect of the anaesthetics. It is concluded that halogenated inhalational anaesthetics are established as bronchospasmolytics, and that their use in bronchospastic disease should be individualized to the patient and his other specific disease process.
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Affiliation(s)
- C M Pedersen
- Odense Sygehus, anaestesi og intensiv afdeling V
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12
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Abstract
The effects of anesthetics on airway smooth muscle tone are important in the management of patients with asthma. In the present study we evaluated the effect of propofol and ketamine on isolated guinea-pig tracheal preparations mounted for recording isometric contractile force. In a concentration-dependent way both drugs produced 100% relaxation irrespective of whether tracheal tone was spontaneous or induced by carbachol, histamine, prostaglandin F2 alpha, 30 mM K+ or 124 mM K+. The relaxant potency of propofol was dependent of the formulation of the drug used. Propofol showed an about 3 times higher potency when solubilized with hydroxypropyl-beta-cyclodextrin compared with an oil-in-water emulsion of the drug (Diprivan). Propofol had the greatest potency on tracheal preparations with spontaneous tone (EC50 = 4.0 +/- 0.9 microM). Ketamine preferentially relaxed contractions elicited by carbachol (EC50 = 120.8 +/- 5.2 microM) and had a lower potency than propofol when tone was spontaneous or induced by other tracheal spasmogens. Since propofol was a more effective tracheal relaxant in vitro than ketamine, the possibility that propofol, like ketamine, may inhibit bronchoconstriction during anesthesia should be studied further.
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Affiliation(s)
- C M Pedersen
- Institute of Pharmacology, University of Aarhus, Denmark
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13
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Pedersen CM, Rasmussen HB, Jensen PB, Jørgensen KA. [Acute renal failure caused by paracetamol poisoning]. Ugeskr Laeger 1993; 155:1720-1. [PMID: 8317017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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14
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Søballe K, Hansen ES, Brockstedt-Rasmussen H, Pedersen CM, Bünger C. Bone graft incorporation around titanium-alloy- and hydroxyapatite-coated implants in dogs. Clin Orthop Relat Res 1992:282-93. [PMID: 1729014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To evaluate cancellous allogenic bone graft incorporation into porous-coated implants, the fixation of titanium alloy-(Ti) and hydroxyapatite-(HA) coated implants with and without bone graft was compared. An unloaded model with unilateral carragheenin-induced osteopenia of the knee was used in 12 mature dogs. Ti- and HA-coated cylinders were implanted in the distal femoral condyles and centralized in 2-mm overreamed drill holes. Allogenic, fresh-frozen (-80 degrees) cancellous bone graft was packed around the implants in six dogs. In a matched group of six other dogs, the implants were left in overreamed canals without bone graft. After six weeks the interface shear strength of grafted Ti-coated implants had significantly increased compared to the nongrafted Ti implants. However, HA coating used without bone graft was capable of enhancing the bone-implant interface shear strength to nearly the same degree. The fixation of grafted Ti- and HA-coated implants was equal. No significant difference in implant fixation was found between osteopenic and control bone. Histomorphometric evaluation of mineralizing surfaces in direct contact with the implant confirmed the results from the push-out test. Bone-implant fixation when using allogeneic fresh-frozen cancellous bone graft in osteopenic and control bone was enhanced by hydroxyapatite coating but the HA coating alone appeared to offer almost the same improvement in anchorage in 2-mm defects. Loss of bone stock around loose prosthetic implants often requires bone grafting. However, because of anatomic constraints in joint prosthetic surgery, a complete filling of defects with bone graft is difficult, and areas of gaps between bone and implant will remain. Provided mechanical stability of the prosthesis, the results reported here suggest that these areas will probably be filled early with new mineralizing bone if the prosthesis is coated with a thin layer of hydroxyapatite.
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Affiliation(s)
- K Søballe
- Orthopaedic Hospital, Biomechanics Laboratory, Aarhus, Denmark
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15
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Abstract
Two patients with chronic obstructive pulmonary disease developed postoperatively bronchospasm after insertion of a prostetic aortic valve. Continuous sedation with propofol infusion was associated with a significant decline in peak inspiratory pressure suggesting that propofol may have bronchodilating properties.
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Affiliation(s)
- C M Pedersen
- Department of Anaesthesiology and Intensive Care, Skejby University Hospital, Aarhus, Denmark
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16
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Søballe K, Hansen ES, Brockstedt-Rasmussen H, Hjortdal VE, Juhl GI, Pedersen CM, Hvid I, Bünger C. Fixation of titanium and hydroxyapatite-coated implants in arthritic osteopenic bone. J Arthroplasty 1991; 6:307-16. [PMID: 1663154 DOI: 10.1016/s0883-5403(06)80181-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Retrieval studies of porous-coated prostheses have demonstrated deficient bony ingrowth in high percentages. Possible reasons for this are lack of initial mechanical stability and the presence of osteopenia. The authors studied ingrowth of osteopenic bone into titanium alloy (Ti) porous-coated implants with and without hydroxyapatite (HA) coating in an experimental dog model. Unilateral osteopenia of the knee with a 20% reduced bone density as judged by computed tomography (CT) scanning (P less than .001) was induced in 12 mature dogs by weekly intraarticular injections of Carragheenin into the right knee for 12 weeks, with the left knee serving as control. Ti porous-coated cylinders were inserted in press-fit bilaterally in the lateral femoral condyles in six dogs. HA-coated titanium plugs were implanted similarly in another sex-, age-, and weight-matched group of six dogs. Bony ingrowth after 4 weeks was significantly reduced for Ti implants in osteopenic bone compared to control bone, but HA-coated implants were covered by equal amounts of bone tissue. Bone-implant shear strength of Ti implants also was reduced in osteopenic bone compared to control bone. In control bone, the anchorage of Ti implants was stronger than HA-coated implants, whereas the fixation of Ti and HA-coated implants was equal in the osteopenic bone. The results demonstrate that the bony fixation of Ti porous-coated implants is weakened by the presence of experimentally induced osteopenia. However, the fixation of HA-coated implants was not affected by the osteopenic condition in the surrounding bone. The fixation of Ti and HA-coated implants was equal in osteopenic bone, whereas the fixation of Ti porous-coated implants was superior to that of HA-coated implants in control bone.
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Affiliation(s)
- K Søballe
- Biomechanics Laboratory, Orthopaedic Hospital, University of Aarhus, Denmark
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17
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Søballe K, Hansen ES, Brockstedt-Rasmussen H, Hjortdal VE, Juhl GI, Pedersen CM, Hvid I, Bünger C. Gap healing enhanced by hydroxyapatite coating in dogs. Clin Orthop Relat Res 1991:300-7. [PMID: 1657476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
During prosthetic implantation, gaps between the implant surface and the surrounding bone may occur resulting in reduced implant stability. In these instances bone-conductive materials might augment the formation of hosting bone into the pores of the implant and insure earlier implant stabilization and fixation by bony ingrowth. Titanium-alloy cylinders with a porous-titanium-alloy plasma spray coating were implanted into the medial femoral condyles in six mature dogs. In another group of six dogs, matched in age, weight, and gender, hydroxyapatite (HA) coated implants were used. All implants were surrounded by a 1-mm gap. Unilateral osteopenia of the knee, with a 20% reduction of bone density as judged by computed tomography scanning, was induced by 12 weekly intraarticular injections of carrageenin into the right knee before surgery. Four weeks after implantation, the HA-coated implants were compared to the parent porous-titanium implants by mechanical testing and histomorphometry. A marked positive influence of HA coating on bone mineralization and the strength of the interfacial bone between the bone and implant was found. The increment in interface shear strength and shear stiffness was three- to fivefold in osteopenic bone and two-fold in control bone. Coating of an unloaded porous-titanium-coated implant with HA accelerates the rate of bone ingrowth and thereby provides relatively high, early interfacial shear strengths in the presence of an initial gap between bone and implant even in the presence of osteopenic host bone.
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Affiliation(s)
- K Søballe
- Orthopaedic Hospital, Biomechanics Laboratory, University of Aarhus, Denmark
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Søballe K, Pedersen CM, Odgaard A, Juhl GI, Hansen ES, Rasmussen HB, Hvid I, Bünger C. Physical bone changes in carragheenin-induced arthritis evaluated by quantitative computed tomography. Skeletal Radiol 1991; 20:345-52. [PMID: 1896875 DOI: 10.1007/bf01267662] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Repeated non-invasive measurements were performed in dogs of trabecular bone density (TBD), low density bone area (LDBA), and high density bone area (HDBA) in chronic arthritis using quantitative computed tomography (QCT). Unilateral chronic arthritis of the knee had been induced by weekly instillation of 2 ml carragheenin into the right knee joint for 12 weeks with the left knee serving as a control. CT scanning of the distal femoral condyles was performed in 12 mature dogs with chronic arthritis. Another 6 dogs underwent a longitudinal CT study starting immediately prior to induction of arthritis. During induction of arthritis TBD decreased (P less than 0.01), LDBA increased (P less than 0.05) and HDBA decreased (P less than 0.01) in the arthritic bone. Opposite changes were found on the control side, i.e. TBD increased (P less than 0.01), LDBA decreased (P less than 0.01) and HDBA increased (P less than 0.01). The chronic arthropathic bone showed 20% lower TBD (P less than 0.0001), greater LDBA (P less than 0.0001) and lower HDBA (P less than 0.0001) as compared with the control bone. Reproducibility tests of TBD showed a coefficient of variation of 0.8%. Indentation tests and histomorphometric analyses confirmed the bone density changes as measured by CT.
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Affiliation(s)
- K Søballe
- Biomechanics Laboratory, Orthopaedic Hospital, University of Aarhus, Denmark
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Søballe K, Hansen ES, Brockstedt-Rasmussen H, Pedersen CM, Bünger C. Hydroxyapatite coating enhances fixation of porous coated implants. A comparison in dogs between press fit and noninterference fit. Acta Orthop Scand 1990; 61:299-306. [PMID: 2402977 DOI: 10.3109/17453679008993521] [Citation(s) in RCA: 118] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Intimate contact at the bone-porous surface interface is not always achievable in noncemented prosthetic implantation. We investigated the effect of hydroxyapatite (HA) coating on skeletal attachment in noninterference fit 4 weeks after implantation in 6 mature dogs. The push-out test of HA-coated implants surrounded by a 1-mm gap showed a twofold increased shear strength and fivefold increased shear stiffness compared with titanium alloy (Ti) coated implants. The fixation of Ti implants was reduced by two thirds when inserted in a gap as compared with press fit, whereas HA-coated implants in gap showed anchorage close to implants in press fit. Only minor differences were found between HA and Ti implants in press fit. Histomorphometric analysis showed a significant increase in bone in direct contact to HA-coated implant as compared with Ti implants inserted both in gap and press fit. The study indicates that tightness of surgical fit is an important factor for sufficient fixation of the implant. However, our results demonstrate that hydroxyapatite coating almost eliminates the negative influence of noninterference fit between bone and unloaded implant.
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Affiliation(s)
- K Søballe
- Orthopedic Hospital, Biomechanics Laboratory, University of Arhus, Denmark
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20
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Abstract
Trabecular bone density changes at the proximal tibia were studied after total and partial meniscectomy using quantitative computerized tomography. Thirty-seven medially meniscectomized patients (5- and 10-year follow-up) and 10 control persons were included. In the partially and the totally meniscectomized knees, the area of maximal density in the medial tibial condyle was displaced approximately 4 mm in a posteromedial direction relative to the position in the intact knees. In both partially and totally meniscectomized knees, the density in the region of tibiofemoral contact in the medial tibial condyle was higher compared with the density in the same region in the contralateral intact knees. This difference was of the same order in the 5- and 10-year follow-up groups. The density difference between the meniscectomized and the intact knees in the region of tibiofemoral contact in the medial condyle was significantly higher in totally than in partially meniscectomized patients. It is concluded that not only total but also partial medial meniscectomy is followed by density changes, occurring within the first 5 years after meniscectomy. The results emphasize the importance of the utmost conservatism in surgery on the meniscus.
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Affiliation(s)
- A Odgaard
- Biomechanics Laboratory, Orthopaedics Hospital, Aarhus, Denmark
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