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1.
Clin Genet ; 90(4): 343-50, 2016 10.
Article in English | MEDLINE | ID: mdl-26916598

ABSTRACT

The basal transcription of heme oxygenase-1 (HO-1) regulation is dependent upon a GT repeat germ line polymorphism (GTn) in the promoter of the HO-1 gene. We determined the prognostic value of HO-1 promoter polymorphism on the natural postoperative course of complete resected oesophageal cancer. Genomic DNA from 297 patients was amplified by polymerase chain reaction and sequenced. The results were correlated with clinicopathological parameters, disseminated tumour cells in bone marrow (DTC) and clinical outcome. Depending on short allele with <25 and long allele with ≥25, GTn repeats three genotypes (SS, SL and LL) were defined. A diverse role of GTn was evident in squamous cell carcinoma (SCC) and adenocarcinoma (AC). In SCC, the SS genotype presented less advanced tumours with lower rate DTC in bone marrow and relapse compared with L-allele carriers. In contrast, AC patients with the SS genotype displayed a complete opposing tumour characteristic. The disease-free (DFS) and overall survival (OS) in SCC patients was markedly reduced in LL genotypes (p < 0.001). In AC contrarily the SS genotype patients displayed the worst DFS and OS (p < 0.001). GTn is a strong prognostic factor with diverse prognostic value for recurrence and survival in AC and SCC.


Subject(s)
Adenocarcinoma/genetics , Carcinoma, Squamous Cell/genetics , Esophageal Neoplasms/genetics , Heme Oxygenase-1/genetics , Polymorphism, Genetic , Promoter Regions, Genetic , Adenocarcinoma/pathology , Adenocarcinoma/surgery , Carcinoma, Squamous Cell/pathology , Carcinoma, Squamous Cell/surgery , DNA Mutational Analysis , Disease-Free Survival , Esophageal Neoplasms/pathology , Esophageal Neoplasms/surgery , Female , Heme Oxygenase-1/chemistry , Humans , Male , Middle Aged , Prognosis , Recurrence , Repetitive Sequences, Nucleic Acid , Treatment Outcome
2.
Rofo ; 186(6): 551-8, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24760428

ABSTRACT

UNLABELLED: Three imaging modalities are available for the diagnosis of acute appendicitis: ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Transabdominal ultrasound should be the first-line imaging test. Abdominal CT is superior to US and is required immediately in patients with atypical clinical presentation of appendicitis and suspected perforation. However, low-dose unenhanced CT is equal to standard-dose CT with intravenous contrast agents in the detection of five signs of acute appendicitis (thickened appendiceal wall more than 2 mm, cross-sectional diameter greater than 6 mm, periappendicitis, abscess, and appendicolith). MRI is necessary in pregnant women and young adults. This review illustrates the principles of state-of-the-art imaging techniques and their clinical relevance. KEY POINTS: • US is the basic diagnostic method in case of suspected appendicitis.• CT is necessary in patients with atypical presentation of appendicitis.• MRI should be the first-line imaging test in pregnant women.


Subject(s)
Appendicitis/diagnosis , Magnetic Resonance Imaging/methods , Tomography, X-Ray Computed/methods , Ultrasonography/methods , Abdomen, Acute/etiology , Adult , Appendicitis/surgery , Appendix/pathology , Diagnosis, Differential , Female , Humans , Pregnancy , Pregnancy Complications/diagnosis , Sensitivity and Specificity
3.
Mini Rev Med Chem ; 13(2): 273-9, 2013 Feb.
Article in English | MEDLINE | ID: mdl-22512581

ABSTRACT

This review addressed the adverse effects of the frequently-used recreational drug, ketamine through using mice and monkey models. Our laboratory has documented initially that ketamine can induce the formation of hyperphosphorlated tau (hypertau), which is a hallmark of Alzheimer's disease (AD), in the cerebral cortex of both mice and monkeys as well as apoptosis in neurons in these species. Besides the cerebral cortex, other centers in the central nervous system (CNS) and peripheral nervous system (PNS) are also influenced by ketamine. Cerebellum was found to be down-regulated in both mice and humans after long-term of ketamine administration and it was caused by the apoptosis of Purkinje cells. Deleterious effects in other organs reported in long-term ketamine users include of kidney dysfunction leading to proteinuria, fibrosis of the urinary bladder and reduction in size of the urinary bladder leading to frequent urination, increase of liver fibrosis and cardiac problems such as premature ventricular beats. Moreover, ketamine is usually co-administrated with other chemicals such as caffeine or alcohol. It has been reported increased harmful effects when ketamine was used in combination with the above substances. Mechanisms of damages of ketamine might be due to 1) up-regulation of NMDA receptors leading to overestimation of glutamatergic system or 2) the metabolite of ketamine which was a hydroquinone exerted toxicity.


Subject(s)
Alcoholic Intoxication/complications , Anesthetics, Dissociative/adverse effects , Ketamine/adverse effects , Models, Animal , Animals , Brain/drug effects , Brain/pathology , Haplorhini , Kidney/drug effects , Kidney/pathology , Liver/drug effects , Liver/pathology , Mice , Urinary Bladder/drug effects , Urinary Bladder/pathology
4.
J Gastrointest Surg ; 17(3): 581-5, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23242846

ABSTRACT

BACKGROUND: Surgical resection represents the only potentially curative treatment for hilar cholangicarcinoma. Because of the aggressive nature and the absence of effective adjuvant therapy treatment remains still a challenge. DISCUSSION: This manuscript reviews management of hilar cholangiocarcinoma with a focus on operative strategy.


Subject(s)
Bile Duct Neoplasms/surgery , Hepatectomy/methods , Hepatic Duct, Common/surgery , Klatskin Tumor/surgery , Bile Duct Neoplasms/diagnosis , Humans , Klatskin Tumor/diagnosis , Male , Middle Aged
5.
Microsc Res Tech ; 75(10): 1334-40, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22581761

ABSTRACT

White button mushroom extract was examined in this study on (1) its potential effect on angiogenesis in chorioallantoic culture and (2) its recovering effect on the skin after injury in the ICR mice. Methods used included TUNEL assay on apoptosis, immunohistochemistry for vascular endothelial growth factor (VEGF), proliferative cell nuclear antigen (PCNA), epidermal growth factor (EGF), transforming growth factor ß (TGF-ß), and immune factor CD4 and western blotting. The results of chorioallantoic culture showed that the mushroom treatment led to significant increase in densities of VEGF sites. In the skin injury, ICR mice model increased EGF, PCNA, and collagen fibers, along with decrease of TUNEL positive apoptotic cells and limited reaction of TGF-ß and CD4 indicated that white button mushroom extract appeared to have beneficial effects on skin in regeneration and after injury.


Subject(s)
Agaricales/chemistry , Chorioallantoic Membrane/drug effects , Neovascularization, Physiologic/drug effects , Skin/drug effects , Wound Healing/drug effects , Agaricus , Animals , Chickens , Gene Expression Profiling , Immunohistochemistry , Mice , Mice, Inbred ICR
6.
Curr Med Chem ; 18(34): 5281-8, 2011.
Article in English | MEDLINE | ID: mdl-22087825

ABSTRACT

Serotonin (5-hydroxytryptamine, 5-HT) is well known to be closely associated with emotional disorders, such as depression and schizophrenia. The seven main members of 5-HT receptor family including the different subtypes are involved in the functional pathways in the brain and their balance in activity helps to maintain the normal mental stability. As any detrimental changes in the 5-HT system is believed to alter emotion in human, different drugs including serotonin reuptake inhibitors (SSRIs) are nowadays commonly used as anti- depressives. In this review, 5-HT(1A) and 5-HT(2A) receptors and serotonergic positive cells in the human were highlighted in particular. It is hoped that this review will give a map of these major 5-HT receptors and serotonergic neurons in the human CNS to facilitate further deciphering of their functions.


Subject(s)
Central Nervous System Agents/metabolism , Receptors, Serotonin/metabolism , Serotonin/metabolism , Animals , Humans , Selective Serotonin Reuptake Inhibitors/pharmacology
7.
Clin Transplant ; 24(1): 48-55, 2010.
Article in English | MEDLINE | ID: mdl-19236435

ABSTRACT

BACKGROUND: Portal vein thrombosis (PVT) is a surgical challenge in liver transplantation (LTx). In contrast to LTx in decompensated liver disease, which are associated with a higher morbidity and mortality, PVT influence on outcome is still under debate. To evaluate this influence at different stages of liver decompensation, we compared the outcome of patients suffering from PVT to patients with patent portal vein within different score ranges. METHODS: We included 193 LTx (24 with PVT) in our study, transplanted between 2004 and 2007 at our institution. Patients were divided into four Model of End-Stage Liver Disease (MELD) score groups, and outcome was compared between PVT- and non-PVT patients. RESULTS: In non-decompensated liver disease (MELD <15), we found a significantly decreased survival in patients suffering from PVT (one-yr survival 57% vs. 89%). By contrast, MELD score >15 (decompensated liver disease) leads to an equal or even better survival in PVT-patients compared with patients without PVT (one-yr survival 91% vs.75%), with an only slightly increased morbidity. CONCLUSION: Outcome in patients with PVT seems to be dependent on pre-operative disease severity. In contrast to compensated liver disease, no influence of PVT on outcome could be found in decompensated liver disease, and should therefore not be considered as a contraindication in LTx.


Subject(s)
Liver Diseases/complications , Liver Diseases/surgery , Liver Transplantation , Portal Vein , Venous Thrombosis/complications , Adult , Aged , Cohort Studies , Female , Humans , Liver Diseases/mortality , Male , Middle Aged , Retrospective Studies , Risk Factors , Severity of Illness Index , Survival Analysis , Treatment Outcome , Venous Thrombosis/mortality , Venous Thrombosis/therapy
8.
Gene Ther ; 16(3): 320-8, 2009 Mar.
Article in English | MEDLINE | ID: mdl-18987674

ABSTRACT

Ischemia/reperfusion (I/R) injury is an unavoidable barrier that significantly affects outcome of solid organ transplantation. Here, we establish a protein transduction system to extend graft preservation time and to prevent I/R injury in heart transplantation. We generated a recombinant heme oxygenase-1 (HO-1) protein containing a modified protein transduction domain (PTD). PTD could cross cover cell membrane and carry target molecule to parenchymal cells of cold-preserved heart grafts. The newly generated PTD-HO-1 protein localized mainly in subcellular membrane organelle and nucleus after delivery that significantly prolonged cold preservation of heart grafts. This effect was associated with significantly less endothelial cell activation, less neutrophil and macrophage infiltration in PTD-HO-1-transduced heart grafts after reperfusion as compared with controls. In addition, transduction of PTD-HO-1 protein to heart graft significantly suppressed the I/R injury-associated myocardiocyte apoptosis. The infarct areas of heart graft after I/R injury were significantly reduced after PTD-HO-1 protein treatment. We show here for the first time that PTD can maintain its biological activities during cold preservation. Transduction of cell penetrating HO-1 protein significantly prolongs the cold preservation time and protects the graft from the I/R injury. This approach represents a novel method for the improvement of the overall outcome of organ transplantation.


Subject(s)
Genetic Therapy/methods , Heart Transplantation , Heme Oxygenase-1/genetics , Reperfusion Injury/prevention & control , Animals , Apoptosis/physiology , Endothelial Cells/physiology , Graft Survival , Heme Oxygenase-1/pharmacokinetics , Myocardium/enzymology , Neutrophil Infiltration/physiology , Rats , Rats, Inbred Lew , Recombinant Proteins/genetics , Refrigeration , Reperfusion Injury/pathology , Time Factors , Transduction, Genetic
9.
Clin Hemorheol Microcirc ; 38(2): 105-18, 2008.
Article in English | MEDLINE | ID: mdl-18198412

ABSTRACT

PURPOSE: Contrast harmonic ultrasound (CHI) with a linear transducer is a new diagnostic approach that allows dynamic and quantitative flow detection of tissue perfusion in microsurgery. The aim of the study was the evaluation of perfusion of the dermal and subdermal layers of microvascular tissue transplants with CHI in comparison to ICG-fluorescence angiography. MATERIAL AND METHOD: In a prospective clinical study Indocyanine-Green Fluorescence Video Angiography and Contrast Enhanced High Resolution Ultrasound (5-10 MHz; linear transducer; Logiq 9; GE) were used for evaluation of the microcirculation in 10 transplanted free parascapular flaps. Two regions were analysed, the centre of the flap and the region of the anastomosis. The perfusion patterns of both methods were compared. RESULTS: The perfusion indexes measured by ICG-fluorescence angiography correlated very precisely in all patients with the quantitative perfusion curves of contrast-enhanced US with CHI. Two flaps with slow filling and low dye intensity showed low contrast enhancement in CHI with modified perfusion curves with slow increase. In two cases a reduced perfusion and filling were found. There were no statistical differences between the two diagnostic methods (p>0.01). CONCLUSION: CHI improves US detections of dermal and subdermal microcirculation in comparison to ICG fluorescence angiography. CHI is a new diagnostic method for postoperative monitoring of free flaps.


Subject(s)
Angiography/instrumentation , Angiography/methods , Contrast Media/pharmacology , Fluorescent Dyes/pharmacology , Indocyanine Green/pharmacology , Microcirculation/diagnostic imaging , Microcirculation/pathology , Skin/blood supply , Surgical Flaps , Ultrasonics , Ultrasonography/instrumentation , Adult , Anastomosis, Surgical , Humans , Image Processing, Computer-Assisted/instrumentation , Image Processing, Computer-Assisted/methods , Microscopy, Video/methods , Middle Aged , Myocardium/pathology , Perfusion , Ultrasonography/methods
10.
Clin Hemorheol Microcirc ; 38(1): 31-44, 2008.
Article in English | MEDLINE | ID: mdl-18094456

ABSTRACT

PURPOSE: Contrast harmonic ultrasound (CHI) with a linear transducer is a new diagnostic approach that allows dynamic and quantitative flow detection of tissue perfusion in microsurgery. The aim of the study was the evaluation of perfusion of the dermal and subdermal layers of microvascular tissue transplants with CHI in comparison to ICG-fluorescence angiography. MATERIAL AND METHOD: In a prospective clinical study indocyanine-green fluorescence video angiography and contrast enhanced high resolution ultrasound (5-10 MHz; linear transducer; Logiq 9; GE) were used for evaluation of the microcirculation in 10 transplanted free parascapular flaps. Two regions were analysed, the centre of the flap and the region of the anastomosis. The perfusion patterns of both methods were compared. RESULTS: The perfusion indexes measured by ICG-fluorescence angiography correlated very precisely in all patients with the quantitative perfusion curves of contrast-enhanced US with CHI. Two flaps with slow filling and low dye intensity showed low contrast enhancement in CHI with modified perfusion curves with slow increase. In two cases a reduced perfusion and filling were found. There were no statistical differences between the two diagnostic methods (p>0.01). CONCLUSION: CHI improves US detections of dermal and subdermal microcirculation in comparison to ICG fluorescence angiography. CHI is a new diagnostic method for postoperative monitoring of free flaps.


Subject(s)
Fluorescein Angiography/standards , Microcirculation/diagnostic imaging , Microscopy, Acoustic/standards , Surgical Flaps/blood supply , Adult , Female , Humans , Indocyanine Green , Male , Microsurgery , Middle Aged , Perfusion , Radiography , Plastic Surgery Procedures , Skin/blood supply
11.
Transplantation ; 71(8): 1124-31, 2001 Apr 27.
Article in English | MEDLINE | ID: mdl-11374414

ABSTRACT

BACKGROUND: In clinical organ transplantation monoclonal antibodies (mAb) to different surface molecules of immunocompetent cells become integral parts of the immunosuppressive therapy. In this study, a mAb against the rat leukocyte common antigen CD45 (RT7) was tested for its immunosuppressive potency after a single perioperative injection. METHODS: Binding and depleting properties of the anti-RT7 mAb were investigated by flow cytometry. In the fully major histocompatibility complex-disparate heart and skin transplantation models (LEW [RT1l]--> LEW.1W [RT1u]), a single dose of anti-RT7 mAb (10 mg/kg) was administered intravenously (day -1). To characterize the long-term acceptance of heart allografts second set skin transplantation (day 100), mixed lymphocyte reaction studies (day 100) and reverse transcriptase-polymerase chain reaction analysis for intragraft cytokine expression (day 200) were performed. RESULTS: The anti-RT7 mAb bound to nearly all hematopoietic lineage cells, but particularly T and NK cells, and profoundly depleted these cells in circulation and lymphoid tissues. Anti-RT7 mAb-treated rats showed long-term acceptance of heart allografts (>200 days; n=12), whereas untreated recipients rejected allografts by day 8 (n=6). In contrast to hearts, primary skin allograft survival was only moderately prolonged. Animals with stable heart allograft acceptance showed normal in vitro lymphocyte proliferation responses to donor and third party antigen. These recipients also acutely rejected second set donor-strain skin grafts without inducing rejection of persisting heart allografts. Reverse transcriptase-polymerase chain reaction analysis of intragraft cytokines showed up-regulation of Fas-ligand and IL-4 mRNA in long-surviving heart allografts. CONCLUSIONS: The findings demonstrate that a single injection of an anti-RT7 mAb in the rat can induce stable long-term acceptance of heart allografts by transient but profound T-cell depletion. Local immunoregulatory mechanisms seem to play a role for maintenance of long-term graft acceptance.


Subject(s)
Antibodies, Monoclonal/pharmacology , Graft Survival/immunology , Heart Transplantation/immunology , Leukocyte Common Antigens/immunology , Skin Transplantation/immunology , Animals , B-Lymphocytes/immunology , Flow Cytometry , Graft Survival/drug effects , Granulocytes/immunology , Immunosuppression Therapy/methods , Killer Cells, Natural/immunology , Rats , Rats, Inbred Lew , T-Lymphocytes/immunology , Transplantation, Homologous
13.
Transplantation ; 69(1): 25-30, 2000 Jan 15.
Article in English | MEDLINE | ID: mdl-10653375

ABSTRACT

BACKGROUND: Donor leukocytes may exert positive immunoregulatory effects on allograft acceptance. Most recent studies have focused on pretreatment protocols. In this study, the effect of postoperative infusion of donor leukocytes on graft survival and the phenotypic and functional requirements for infused cells were investigated in fully major histocompatibility complex (MHC)-mismatched rat heart transplant models. METHODS: LEW (RT1l) heart grafts were implanted heterotopically into abdomens of LEW.1W (RT1u), and different types of cells were infused postoperatively. Immunohistochemistry was used to evaluate histopathological changes of grafts. RESULTS: In the absence of any immunosuppressive agents, a single dose of viable donor spleen cells (SC), but not bone marrow cells, was able to prolong heart allograft survival to about 21 days, while they were rejected promptly at day 7 in controls. Infusion of T cell-depleted donor SC, irradiated donor SC or third-party (BN) SC showed no effect on graft survival. Compared with resting cells, neither in vitro nor in vivo prestimulation of infused donor SC improved graft survival. Clinical signs of graft-versus-host reaction were not observed in all above groups. Histology showed remarkable reduction in the severity of graft infiltrate and interleukin-2 receptor-positive cells in grafts of cell-treated animals. Postoperative infusion of SC of F1 generation between different strain combinations showed two requirements for infused cells to be effective: (1) expression of donor-type MHC antigens and (2) strong alloreactivity against the host MHC antigens. CONCLUSION: Postoperative infusion of viable donor SC can lead to allospecific down-regulation of alloreactivity by a graft-versus-host-associated effect.


Subject(s)
Cell Transplantation , Heart Transplantation/immunology , Immunosuppression Therapy/methods , Postoperative Care , Spleen/cytology , Animals , Female , Graft Survival , Graft vs Host Reaction/physiology , Histocompatibility Testing , Immunohistochemistry , Major Histocompatibility Complex/immunology , Male , Myocardium/metabolism , Myocardium/pathology , Rats , Rats, Inbred BN , Rats, Inbred Lew , Time Factors , Tissue Donors , Transplantation, Homologous
14.
Nat Med ; 5(11): 1292-7, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10545996

ABSTRACT

With an organ transplant, hematopoietic donor cells are transferred to the recipient. To study the relevance of the resulting microchimerism for allograft acceptance, we analyzed a rat model of cyclosporine-induced tolerance for strongly incompatible heart allografts. Using a monoclonal antibody that detects a donor-specific CD45 allotype (RT7a), we selectively depleted donor leukocytes at different times after transplantation (days 0 or 18). Depletion was similarly effective at both times. However, only depletion on day 0 prevented tolerance induction and was associated with severe acute or chronic graft rejection. This indicates that passenger leukocytes have an essential immunomodulatory effect on the induction phase of allograft acceptance.


Subject(s)
Graft Survival/immunology , Heart Transplantation/immunology , Leukocytes/immunology , Transplantation Chimera , Animals , Antibodies, Monoclonal/therapeutic use , Base Sequence , Cytokines/genetics , DNA Primers , Graft Survival/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Inbred Lew , Reverse Transcriptase Polymerase Chain Reaction , Transplantation, Homologous
15.
J Biomed Mater Res ; 44(2): 191-7, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10397920

ABSTRACT

The nanoindentation technique was used to characterize the variation in the elastic modulus and hardness of human lumbar vertebral cortical and trabecular bone. The elastic modulus (and in most cases, the hardness as well) of axially aligned trabeculae cut in the transverse direction was significantly greater than in other orientations of vertebral cortical and trabecular bone. In all cases, the elastic modulus and hardness of bone in the load-bearing direction was greater than in corresponding bone types cut in the other directions. Scanning electron micrographs of cortical shell revealed the Haversian-like canal systems expected in secondary cortical bone, but it was difficult to differentiate by morphology cortical from trabecular bone in the human lumbar vertebrae.


Subject(s)
Lumbar Vertebrae/anatomy & histology , Lumbar Vertebrae/physiology , Aged , Biomechanical Phenomena , Elasticity , Female , Humans , Male , Microscopy, Electron, Scanning , Middle Aged , Stress, Mechanical
16.
J Biomed Mater Res ; 45(1): 48-54, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10397957

ABSTRACT

The elastic properties of several microstructural components of dry human vertebrae (T-12 and L-1) and tibiae have been investigated in the longitudinal and transverse directions using nanoindentation. The largest Young's modulus was that for the interstitial lamellae in the longitudinal direction (25.7 +/- 1.7 GPa). This was followed in decreasing order by osteons in the longitudinal direction (22.4 +/- 1.2 GPa), trabeculae in the longitudinal direction (19.4 +/- 2.3 GPa), an average over osteons and interstitial lamellae in the transverse direction [16.6 +/- 1.1 GPa (it was difficult to microstructurally distinguish osteons from interstitial lamellae in the transverse direction)], and trabeculae in the transverse direction (15.0 +/- 2.5 GPa). An ANOVA statistical analysis revealed that the values all are significantly different (p < 0.05). Since the elastic moduli in the longitudinal direction are all greater than in the transverse, measurable elastic anisotropies exist in the components. The hardnesses also varied among the microstructural components in the range 0.52-0.74 GPa.


Subject(s)
Bone and Bones/physiology , Aged , Algorithms , Anisotropy , Bone and Bones/ultrastructure , Elasticity , Female , Hardness , Humans , In Vitro Techniques , Male , Middle Aged , Tibia/physiology , Tibia/ultrastructure
17.
J Biomech ; 32(4): 437-41, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10213035

ABSTRACT

Acoustic microscopy (30-60 microm resolution) and nanoindentation (1-5 microm resolution) are techniques that can be used to evaluate the elastic properties of human bone at a microstructural level. The goals of the current study were (1) to measure and compare the Young's moduli of trabecular and cortical bone tissues from a common human donor, and (2) to compare the Young's moduli of bone tissue measured using acoustic microscopy to those measured using nanoindentation. The Young's modulus of cortical bone in the longitudinal direction was about 40% greater than (p<0.01) the Young's modulus in the transverse direction. The Young's modulus of trabecular bone tissue was slightly higher than the transverse Young's modulus of cortical bone, but substantially lower than the longitudinal Young's modulus of cortical bone. These findings were consistent for both measurement methods and suggest that elasticity of trabecular tissue is within the range of that of cortical bone tissue. The calculation of Young's modulus using nanoindentation assumes that the material is elastically isotropic. The current results, i.e., the average anisotropy ratio (E(L)/E(T)) for cortical bone determined by nanoindentation was similar to that determined by the acoustic microscope, suggest that this assumption does not limit nanoindentation as a technique for measurement of Young's modulus in anisotropic bone.


Subject(s)
Femur/physiology , Aged , Algorithms , Bone Density , Elasticity , Femur/ultrastructure , Hardness , Humans , Male , Microscopy , Stress, Mechanical , Ultrasonography
18.
Biomaterials ; 18(20): 1325-30, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9363331

ABSTRACT

An experimental investigation was undertaken to measure the intrinsic elastic properties of several of the microstructural components of human vertebral trabecular bone and tibial cortical bone by the nanoindentation method. Specimens from two thoracic vertebrae (T-12) and two tibiae were obtained from frozen, unembalmed human male cadavers aged 57 and 61 years. After drying and mounting in epoxy resin nanoindentation tests were conducted to measure Young's modulus and the hardness of individual trabeculae in the vertebrae and single osteons, and interstitial lamellae in the tibiae. Measurements on the vertebral trabeculae were made in the transverse direction, and the average Young's modulus was found to be 13.5 +/- 2.0 GPa. The tibial specimens were tested in the longitudinal direction, yielding moduli of 22.5 +/- 1.3 GPa for the osteons and 25.8 +/- 0.7 GPa for the interstitial lamellae. Analysis of variance showed that the differences in the measured moduli are statistically significant. Hardness differences among the various microstructural components were also observed.


Subject(s)
Spine/chemistry , Spine/physiology , Tibia/chemistry , Tibia/physiology , Elasticity , Humans , Male , Microchemistry , Middle Aged
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