Cancellous Bone Tissue Research Articles

A method for determining the biomechanical properties of trabecular and spongiosa bone tissue

With the aim of determining the biomechanical properties of cancellous bone, a method was developed that permits the investigation of the effects of tensile and compressive forces on cancellous bone trabeculae while eliminating the problem of porosity. Individual, rod-like trabeculae were removed from cancellous bone with the aid of special instruments. Each end of a trabeculae was embedded in a cylinder of polymethylmethacrylate. To keep bending moments to a minimum while testing, the trabeculae was aligned along the longitudinal axis of the cylinders with the aid of positioning instruments. With a test apparatus, the deformation behaviour and maximum strength of the trabeculae under tension and compression can be determined under both dry and moist conditions. With account being taken of shape and dimensions of the trabeculae, the material properties of the cancellous bone tissue can be computed. In comparison with the small number of methods so far used for investigating trabeculae, a number of advantages were found: 1. Tensile and compression testing in a single specimen, 2. testing under reliably moist conditions, 3. non-destructive testing enabling further investigations on the specimen.

Comparison of the electrical and dielectric behavior of wet human cortical and cancellous bone tissue from the distal tibia

We compared the electrical and dielectric properties of wet human cortical and cancellous bone tissue from the distal tibia. The relationships between the electrical and dielectric behavior of cortical and cancellous bone and variables of measurement such as frequency and direction (orientation) were evaluated. In general, the resistivity of human cortical bone was found to be approximately 3.1 times more than that of cancellous bone in the longitudinal direction and least 25 times more in the transverse directions. The dielectric permittivity of human cortical bone was approximately 3.9 times that of cancellous bone in the longitudinal direction, whereas in the transverse directions it was about 0.65 times greater. Measurement variables such as frequency and orientation appeared to affect cancellous and cortical bone differently. Strong correlations were found between the electrical properties in one direction and the electrical properties in the other two directions; however, these relationships differed for the samples of cortical and cancellous bone.

Microradiographic aspect on iliac bone tissue in postmenopausal women with and without vertebral crush fractures

Bone mass, microstructure and microconnectivity of cancellous bone tissue, microporosity, and microdensity of cortical bone have been evaluated with an image analysing computer on microradiographs in 34 iliac crest bone biopsies from two individual, paired age-matched groups of postmenopausal women. Group 1 comprised 17 cases without vertebral crush fractures (mean age 66 years, range 45–80 years) and time since menopause 20.5 ± 11.5 years. The second group were 17 cases with vertebral crush fractures (mean age 67 years, range 48–86 years) and time since menopause 16.5 ± 7.6 years. No differences were observed either in bone mass or in Parfitt's indices of the microarchitecture of their cancellous bone tissue. However, both groups 1 and 2 were different by the number of the structure elements per 30 mm 2 of tissue volume and the trabecular bone pattern factor (TBPF) being higher in group 1 than in group 2 ( p < 0.005)—showing a better connectivity of bone network in group 2 with crush vertebral fractures than in group 1. The number of terminus to terminus struts of the trabecular bone pattern is increased in group 1 ( p < 0.001). On 7-μm stained sections the active cancellous eroded perimeter (Cn.Oc.Pm/B.Pm) is greater in group 1 than in group 2 ( p < 0.02). Therefore, in these two populations with a similar degree of osteopenia, a decrease of trabecular connectivity does not provide an explanation of bone fragility and the occurrence of vertebral crushed fractures.

Penetration of piperacillin-tazobactam into cancellous and cortical bone tissues

The penetration characteristics of piperacillin-tazobactam into cortical and cancellous bone tissues were investigated in 10 patients undergoing total hip replacement. The concentration ratios of piperacillin/tazobactam were 9.4 +/- 1.8 in cancellous bone tissue and 8.0 +/- 2.2 in cortical bone tissue, which were close to the 8:1 ratio of drugs administered. The mean ratios of drug concentrations in bone and plasma for cancellous and cortical tissue were 23 and 18%, respectively, for piperacillin and 26 and 22%, respectively, for tazobactam. The concentrations of tazobactam achieved are sufficient to exert anti-beta-lactamase activity and supportive of clinical trials involving bone and joint infections, including those caused by beta-lactamase-producing pathogens.

閉経後女性における骨髄組織の変化と骨量減少の関係の加齢変化

We studied histomorphometrically an age-related change of the interaction between cancellous bone and bone marrow hematopoietic tissue in postmenopausal women. Iliac bone biopsy specimens from 75 women undergoing surgery for osteoarthrosis of the hip were used. Subjects were classified into the following three age groups: 60-69 years, 70-79 year, 80-89 year. The number of cases in each group was 21, 30 and 24, respectively.As indices of histomorphometry, the percentage of hematopoietic tissue in bone marrow (H. Ar/M. Ar) and of cancellous bone in the tissue area (Cn-B. Ar/T. Ar) were measured using a microscope connecting a digitizer with a computer system. The values of H. Ar/M. Ar were divided into the following 3 groups. Group 1: more than 35%, Group 2: less than 35% but more than 20%, and Group 3: less than 20%. The mean values of Cn-B. Ar/T. Ar in each Group decreased significantly as the values of H. Ar/M. Ar decreased. The decrease of Cn-B. Ar/T. Ar in Group 3 was remarkable in the 7th and 8th decades in comparison with that of subjects in their 6th decade.These findings indicate a close relationship between decreasing hematopoietic tissue and decreasing bone volume in the bone marrow with increasing age in postmenopausal women.

Sensitivity to a low calcium diet in different bones: an experimental study in the adult rat.

Adult male Sprague-Dawley rats weighing an average of 550 g were age matched into one control group and one group given a low calcium diet. The animals were followed for 34 wk. There was a similar loss of cancellous bone tissue in the proximal tibia, the first tail vertebra and the mandible due to calcium deficiency. The bone loss was not related to the initial amount of cancellous bone or to the bone-forming activity, which did not differ between experimental and control animals.

X-ray microanalysis of fluoride distribution in microfracture calluses in cancellous iliac bone from osteoporotic patients treated with fluoride and untreated

Fluoride is able to augment cancellous bone mass in vertebral osteoporosis but is responsible for osteoarticular side effects in which microfractures are thought to be involved. During healing of these microfractures, a callus is formed all around the cancellous fracture line. Our hypothesis is that in fluoride-treated osteoporotic patients, calluses are bone sites where fluoride is focally deposited at a high concentration, and this could induce a local defect of calcification with a poor healing of microfractures. Our aim was to validate this hypothesis on several calluses following microfractures in undecalcified iliac cancellous bone from six women with osteoporosis (four fluoride treated and two untreated). Histologically normal iliac cancellous bone tissue, taken from a subject having neither fluoride treatment nor microfracture, was also examined. Selected areas, including new woven bone (calluses) and old lamellar bone, were carbon-coated and analyzed using an electron microprobe. Fluoride K alpha and calcium K alpha radiations were detected with wavelength and energy-dispersive spectrometers, respectively. In old lamellar bone at a distance from microfractures, the fluoride level was similar in normal and untreated osteoporotic patients but was slightly increased in treated osteoporotic patients. In untreated osteoporotic patients, the fluoride level was slightly higher (about 1.2 times) at the site of microfractures (lamellar and woven bone) than in lamellar bone far from such fractures, but fluoride was homogeneously distributed in lamellar and woven bone.(ABSTRACT TRUNCATED AT 250 WORDS)

Restoration of axial and appendicular bone volumes by h-PTH(1–34) in parathyroidectomized and osteopenic rats

Effects of h-PTH(1–34) were histomorphometrically evaluated in both cancellous and cortical bone tissues of axial and appendicular skeletons of parathyroidectomized and osteopenic rats. Osteopenia was induced by hemicordotomy immobilization and by estrogen depletion as a result of ovariectomy. The rats received intramuscular injections of 50 units (15 μg) of h-PTH(1–34) six times weekly during weeks 11 through 18 of the experiment. Significant restoration of cancellous and cortical bone volumes was observed in axial and appendicular skeletons of animals treated with h-PTH(1–34). The stimulatory effects of h-PTH(1–34) on osteoid surface, independent of eroded surface, in cancellous and cortical bone tissues, were clearly observed histomorphometrically. Mineralizing surface, mineral apposition rate and bone formation rate in cancellous bone tissues were markedly increased by h-PTH(1–34). It should be noted that h-PTH(1–34) increased trabecular thickness, but did not increase trabecular number. In conclusion, h-PTH(1–34) stimulated bone formation independent of bone resorption, and restored cancellous and cortical bone volumes in parathyroidectomized and osteopenic rats.

Transmission electron microscopy of bone tissue: A review

Remodeling permits the bone to preserve its static and dynamic functions. If this process is disturbed the bone becomes more susceptible to fracture. Remodeling also allows the bone to play a major role as a bank of mineral substances, mainly calcium and phosphorus. The remodeling activities, a very precise sequence of events, concerns compact bone tissue of cortices, as well as cancellous bone tissue. After activation, leading to the birth of osteoclasts from hemopoietic stem cells, there is an osteoclastic resorption forming Howship lacunae. Then, and following a reversal phase, osteoblasts come from osteoprogenitor cells and rebuild bone tissue during the formation phase. There is a coupling, in space and time, between resorption and formation activities (Frost 1973). The purpose of this paper is to review the transmission electron microscopy aspects of bone tissue in order to evaluate (a) the composition of calcified and not yet calcified matrix, (b) the structure and role of osteoclasts and osteoblasts, (c) the aspects of bone cells not directly involved in bone remodeling, such as osteocytes and lining cells.

Experimental method for the measurement of the elastic modulus of trabecular bone tissue.

A procedure has been developed to measure the elastic modulus of small, irregularly shaped specimens without significantly disturbing the specimen's internal or surface structure. This procedure was developed to measure the average elastic modulus of isolated trabeculae from human cancellous bone tissue. The procedure combines direct testing of a cantilever beam-type specimen, along with finite element modeling of the specimen and the testing conditions. Initial estimates for the bone tissue material properties are input into the finite element model; differences between the calculated finite element displacement and the experimentally observed displacement allows the actual material modulus to be determined. Machined aluminum and cortical bone specimens were used to test the accuracy and repeatability of the procedure. Manipulations of the finite element models were performed to examine the effect that mesh construction errors might have on the accuracy of the results. None of the parameters examined resulted in changes in the measured finite element displacements of greater than 8%. In tests on six trabecular bone specimens, an average elastic modulus of 7.8 GPa was calculated. Even taking into account the possible sources of error, this value remains significantly less than the accepted value for cortical bone.

Time course of vertebral osteopenia in ovariectomized rats

Osteopenic changes in cancellous bone tissue of the first lumbar vertebral body were characterized in ovariectomized (OVX) rats as a function of time. Female Sprague Dawley rats (240 g body weight, 90 days old) were subjected to bilateral ovariectomy or sham surgery and sacrificed at various times from 0–540 days postovariectomy. The first lumbar vertebra was processed undecalcified for quantitative bone histomorphometry. Cancellous bone volume remained relatively constant in control rats at ~40% throughout the duration of the study. In contrast, cancellous bone volume was moderately decreased to 30–35% in OVX rats out to 180 days postovariectomy. Vertebral osteopenia became more pronounced in OVX rats at later times as cancellous bone volume declined to ~20% between 180 and 270 days and remained at that osteopenic level for the duration of the study. Osteoblast and osteoclast surface were highly elevated in OVX rats at 35 days, declined gradually toward control levels out to 180 days, then increased markedly at 270 days. Mineralizing surface and bone formation rate (tissue level, total surface referent) were maximally increased in OVX rats at 35–70 days before declining toward control levels at later times. However, these parameters remained significantly increased in OVX rats relative to control rats between 270 and 540 days. Mineral apposition rate was nearly identical in control and OVX rats at all time points and declined linearly with age in both groups. Our results indicate that osteopenia and increased bone turnover occur in the lumbar vertebral bodies of OVX rats, as had been previously observed in the proximal tibial metaphyses of these animals. However, vertebral osteopenia develops more slowly and is less pronounced than tibial osteopenia in OVX rats. This temporal characterization of osteopenic changes in OVX rats may serve as a basis for the design of future studies with the OVX rat as an animal model for postmenopausal bone loss.

Errors induced by off-axis measurement of the elastic properties of bone.

Misalignment between the axes of measurement and the material symmetry axes of bone causes error in anisotropic elastic property measurements. Measurements of Poisson's ratio were strongly affected by misalignment errors. The mean errors in the measured Young's moduli were 9.5 and 1.3 percent for cancellous and cortical bone, respectively, at a misalignment angle of 10 degrees. Mean errors of 1.1 and 5.0 percent in the measured shear moduli for cancellous and cortical bone, respectively, were found at a misalignment angle of 10 degrees. Although, cancellous bone tissue was assumed to have orthotropic elastic symmetry, the possibility of the greater symmetry of transverse isotropy was investigated. When the nine orthotropic elastic constants were forced to approximate the five transverse isotropic elastic constants, errors of over 60 percent were introduced. Therefore, it was concluded that cancellous bone is truly orthotropic and not transversely isotropic. A similar but less strong result for cortical bone tissue was obtained.

On the dependence of the elasticity and strength of cancellous bone on apparent density

This paper presents a statistical analysis of the pooled data from a number of previous experiments concerning the dependence of the Young's moduli and strength of cancellous bone tissue upon apparent density. The results show that both the Young's moduli and the strength are proportional to the square of apparent density of the tissue and are therefore proportional to one another. It is shown that the coefficient of proportionality is different for human and bovine tissue. It is concluded that the suggestion of Wolff ( Das Gesetz der Transformation der Knochen, Hirschwald, Berlin, 1892) that compact bone tissue is simply more dense cancellous bone tissue is not an accurate statement when only the mechanical properties of these two tissues are considered. It is noted that estimates for the elastic modulus of the individual trabecula of human cancellous bone vary from 1 to 20 GPa and it is suggested that this question needs further study.

Is n-butyl-2-cyanoacrylate a biocompatible coating material for biodegradable fracture fixation devices? An experimental study on rats

The effect of n-butyl-2-cyanoacrylate monomer and polymer on the repair characteristics of cancellous bone was evaluated in an experimental study in which 105 male Wistar rats were operated on. A transverse drill channel 2mm in diameter and 5mm long in the femoral condyle was filled with a cylindrical implant of n-butyl-2-cyanoacrylate polymer or liquid n-butyl-2-cyanoacrylate monomer, which was polymerized in the tissue. The drill channel was left empty in the control group. Follow-up periods were one, three, six, 12, 24, 36 and 48 weeks. Radiographic, histologic, histomorphometric, oxytetracycline fluorescence and microradiographic studies were done. N-butyl-2-cyanoacrylate polymerdid not delaybone healing and was well tolerated by rat's cancellous bone tissue without signs of foreign body reaction or prolonged inflammation reaction. The polymerization of n-butyl-2-cyanoacrylate monomer caused the development of a narrow zone of bone necrosis or connective tissue around the implant depending on whether or not blood had interfered in the polymerization reaction. Bone necrosis and connective tissue worked as a biological and mechanical obstruction for bone healing towards the implant although there was no disturbance in the regenerative process in the trabecular network surrounding the implant.

Wolff's law of trabecular architecture at remodeling equilibrium.

An elastic constitutive relation for cancellous bone tissue is developed. This relationship involves the stress tensor T, the strain tensor E and the fabric tensor H for cancellous bone. The fabric tensor is a symmetric second rank tensor that is a quantitative stereological measure of the microstructural arrangement of trabeculae and pores in the cancellous bone tissue. The constitutive relation obtained is part of an algebraic formulation of Wolff's law of trabecular architecture in remodeling equilibrium. In particular, with the general constitutive relationship between T, H and E, the statement of Wolff's law at remodeling equilibrium is simply the requirement of the commutativity of the matrix multiplication of the stress tensor and the fabric tensor at remodeling equilibrium, T*H* = H*T*. The asterisk on the stress and fabric tensor indicates their values in remodeling equilibrium. It is shown that the constitutive relation also requires that E*H* = H*E*. Thus, the principal axes of the stress, strain and fabric tensors all coincide at remodeling equilibrium.

The Function of Bone Marrow in the Incorporation of a Bone Graft

Transplants of bone marrow into the anterior chamber of the eye were observed by Pfeiffer to produce migration, regression, and degeneration of myelogenous and hematopoietic cells at the same time that reticular cells proliferate and differentiate into bone. This key observation raised the question of whether the bone formation is the result of proliferation and osteogenetic activity of the reticular cells, or whether mesenchymal-type cells of the host are also induced by the transplant to differentiate into bone. From a comparison of bone marrow with epiphyseal cartilage, fracture callus, cancellous bone, muscle, and other tissues. Urist and McLean suggested that in the anterior chamber of the eye, one or another, or both, mechanisms are operative. Urist demonstrated that new bone formation occurs in postfetal life by the mechanism of induction alone in an implant of demineralized bone matrix in a muscle pouch. In recent years, the inductive agent and inductive response have been under intensive investigation with the aid of new and improved biochemic concepts and methods (Lindholm and Urist).

Influence of the Stage of Dairy Cow Reproduction Cycle on Some Clinico-biochemical Parameter

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Changes in dimensions of large cancellous bone specimens during histological preparation as measured on slabs from human femoral heads.

Distortion of the dimensions of large cancellous bone specimens during all stages of histological processing and cutting of paraffin sections in various directions was measured on Xerograms taken from slabs and then sections from human femoral heads. Although some shrinkage in both width and height of the specimens occurred at every stage of the histological preparation, the main shrinkage (about 6%) occurred during the embedding process, and mainly in the cutting of the sections (10-27%, depending on the direction the knife was approaching the specimen). The shrinkage of cancellous bone tissue during histological preparation appears to be a constant factor, but its magnitude during the individual stages of the preparation can be predicted. For the quantitative measurements a comparison of two Xerograms--one taken from the original fresh bone slab and the other from the final stained section--would reveal the exact extent of the tissue shrinkage.

Microvascular response in cancellous bone to halothane-induced hypotension in pigs

The microvascular response in cancellous bone to halothane-induced hypotension was studied simultaneously using Laser Doppler Flowmetry (LDF) and clearance of locally injected 133Xe in the subapical mandibular bone of 16 young pigs. During halothane inhalation, a significant reduction in mean blood pressure to values ranging from 22 to 60 mm Hg was observed. The blood flow, as measured with LDF, increased in more than 60% of the animals with hypotension levels above 30 mm Hg. At hypotension levels below 30 mm Hg, blood flow decreased in all cases. The individual regional vascular resistance, calculated as the quotient between blood pressure and recorded blood flow value, was significantly reduced ( p<0.001) during hypotension. Rhythmical flow variations, observed in some animals at normotension, disappeared immediately following the start of halothane inhalation, but returned when blood pressure was stabilized at a lower level. For recordings made with 133Xe-clearance, a significant reduction ( p<0.001) in the logarithmic decay of the washout curves was observed during hypotension. This logarithmic decay was correlated to the reduced blood pressure levels ( r=0.73). No average change in regional vascular resistance could, however, be demonstrated. The lack of correlation between results obtained by the 2 methods may be due to the fact that LDF is sensitive to the total blood flow in a limited tissue volume, while the 133Xe isotope seems to be washed out mainly by the capillary blood flow. It can be further concluded that halothane-induced hypotension levels, applicable to clinical routines, may produce an increase rather than a decrease in total blood flow in cancellous bone tissue.

Effect of 1 alpha-hydroxyvitamin D3 on cancellous bone matrix. An experimental study on adult rats.

Two groups of adult male rats were treated perorally for 6 weeks with 0.1 microgram and 1.0 microgram of 1a-hydroxyvitamin D3 (1a-OH-D3), respectively. The effect of the treatment on cancellous bone matrix was studied by chemical analysis and morphometric measurements. The effect of the 1.0 microgram dose on the inorganic composition, and on the calcification of the cancellous bone matrix, was significantly more pronounced, decreasing the amount of glycosaminoglycans. The lower dose level, 0.1 microgram of 1a-OH-D3, increased the collagen metabolism, whereas the higher dose level did not. The amount of cancellous bone determined morphometrically increased significantly during treatment with both dose levels. 1a-OH-D3, converted in the organism to the hormonal form 1.25 (OH)2D3, induces new bone formation, probably by direct influence on the cancellous bone tissue itself.