Changes In Bone Tissue Research Articles

Comparative Study of Compact Bone Tissue Microstructure between Non-transgenic and Transgenic Rabbits with WAP-hFVIII Gene Construct

The aim of this study was to investigate differences in compact bone tissue microstructure between New Zealand White transgenic rabbits with human blood clotting factor VIII gene and the non-transgenic ones. The transgene was under the transcriptional control of the whey acidic protein (WAP) promoter. Altogether, 42 femora were analysed. Specimens were prepared using standard histological equipment, producing thin sections approximately 80-100 microm. Areas, perimeters, minimum and maximum diameters of vascular canals of primary osteons, Haversian canals and secondary osteons were measured. Our results indicate the basic structural pattern of the bone tissue was primary vascular longitudinal in both groups of rabbits. However, a fibrolamellar bone tissue was identified only in the transgenic rabbits. The measured variables of the vascular canals of the primary osteons, the Haversian canals and the secondary osteons were higher in transgenic rabbits in comparison with non-transgenic ones in most cases and the differences were often statistically significant (P < 0.01; P < 0.001). More significant differences were noticed in males (transgenic versus non-transgenic). However, it is not easy to find the real cause of the changes. Despite the fact that no hFVIII mRNA expression was found in the analysed bone of transgenic rabbits, we presume that the observed differences could be associated with transgenesis. In this article, we discuss possible associations between transgene integration as well as aneuploidy and/or observed microstructural changes in compact bone tissue.

Perinatal exposure to PCB 153, but not PCB 126, alters bone tissue composition in female goat offspring

The aim of this study was to investigate if environmentally relevant doses of the putative estrogenic non dioxin-like PCB 153 and the dioxin-like PCB 126 caused changes in bone tissue in female goat offspring following perinatal exposure. Goat dams were orally dosed with PCB 153 in corn oil (98 μg/kg body wt/day) or PCB 126 (49 ng/kg body wt/day) from day 60 of gestation until delivery. The offspring were exposed to PCB in utero and through mother's milk. The suckling period lasted for 6 weeks. Offspring metacarpal bones were analysed using peripheral quantitative computed tomography (pQCT) after euthanisation at 9 months of age. The diaphyseal bone was analysed at a distance of 18% and 50% of the total bone length, and the metaphyseal bone at a distance of 9%. Also, biomechanical three-point bending of the bones was conducted, with the load being applied to the mid-diaphyseal pQCT measure point (50%). PCB 153 exposure significantly decreased the total cross-sectional area (125 mm 2 ± 4) versus non-exposed (142 mm 2 ± 5), decreased the marrow cavity (38 mm 2 ± 4) versus non-exposed (50 mm 2 ± 3) and decreased the moment of resistance (318 mm 3 ± 10) versus non-exposed (371 mm 3 ± 20) at the diaphyseal 18% measure point. At the metaphyseal measure point, the trabecular bone mineral density (121 mg/cm 3 ± 5) was increased versus non-exposed (111 mg/cm 3 ± 3). PCB 126 exposure did not produce any observable changes in bone tissue. The biomechanical testing of the bones did not show any significant changes in bone strength after PCB 153 or PCB 126 exposure. In conclusion, perinatal exposure to PCB 153, but not PCB 126, resulted in altered bone composition in female goat offspring.

Quantitative ultrasound technique at the phalanges in discriminating between uremic and osteoporotic patients

This study was conducted to test the ability of quantitative ultrasound technique (QUS) at the phalanges to discriminate between uremic and osteoporotic patients. Three groups of subjects (38 dialytic women, 16 osteoporotic women with vertebral fractures, 19 non-dialytic and non-fractured women) were recruited at the Department of Radiology at “Casa Sollievo della Sofferenza” Hospital, San Giovanni Rotondo, Italy. The groups were matched for age and body mass index (BMI). On all subjects the following measurements were performed: spinal BMD by QCT and by DXA, Femoral BMD by DXA, phalangeal QUS. For QUS measurements, the DBM Sonic (IGEA, Carpi, Italy) was applied to the metaphysis of the proximal phalanges of the last four fingers of the hand. Osteoporotic women with vertebral fractures showed significantly lower values of spinal BMD by QCT and DXA and Ward's Triangle BMD with respect to hemodialytic patients ( p < 0.005). All QUS values, except for BTT and SoS, showed lower values in osteoporotic women with respect to hemodialytic patients ( p < 0.05). Control group showed higher values of AD-SoS, BTT and SoS than hemodialytic patients ( p < 0.005) while the two groups did not differ for BMD values measured with both QCT and DXA. UBPI and FWA data showed a similar behaviour to DXA and QCT results, whereas BTT and SoS showed a completely different behaviour. AD-SoS was the only parameter that could effectively discriminate among the three groups (ANOVA, p < 0.0001). We conclude that phalangeal QUS can discriminate between hemodialysed patients and controls with similar bone mineral density, and can also discriminate between hemodialysed and osteoporotic subjects with vertebral fractures. Different characteristics of ultrasound signal can be ascribed to each bone tissue condition, enabling a clear differentiation of bone tissue changes occurring in menopause, osteoporosis and renal osteodystrophy.

Treatment of the Irradiated Patient With Dental Implants: The Case Against Hyperbaric Oxygen Treatment

The controversy concerning placement of dental implants into bone that has been irradiated has a long history. Much work has been done experimentally and clinically to elucidate the mechanism of radiation injury to bone. Understanding the principles believed to result in radiation injury is important, but the clinician, even armed with the most relevant and up to date knowledge, must weigh hyperbaric oxygen therapy (HBO) versus alternatives. When the alternative is nothing, the decision becomes more difficult. There is considerable evidence that radiation injury damages the vasculature, the cells, enhances susceptibility to infection, and creates a wound healing problem. First, any discussion of this problem must separate implant healing in previously radiated bone from radiation of bone containing implants and bone graft healing after transplantation. This article limits itself to questions related to placement of dental implants into previously irradiated bone. Major questions exist regarding several critical issues. The amount of radiation is critical with more than 5,000 cGy, which is often cited as a level for concern. The location of implant placement is critical because common understanding is that the mandible is more susceptible to injury than the maxilla and the symphysis area most resistant. Even this dictum deserves discussion given more recent information. Was the bone to receive implants in the field of radiation? Of great interest and importance, based on existing clinical studies, is the question of whether or not radiation injury is progressive or if it reaches a stable end point, thus enabling placement at a safe time. Thus, the time from radiation therapy to implant placement is critical to success. Time has 2 dimensions regarding clinical judgment. The first, should implants be placed close to the time of completion of radiation therapy for best results, or should one wait a year to place implants? The biologic basis for each has some support. In the former, evidence exists in soft and hard tissue that the acute changes of radiation injury are less detrimental than the chronic changes. The argument for delayed placement is based on the evidence that after a critical length of time, the bone and soft tissue changes following radiation therapy stabilize.

STRUCTURAL AND FUNCTIONAL CHANGES IN BONE TISSUE OF THE SPINE AND EXTREMITIES IN OXYS RATS

Objective. To study specific structural and functional changes in bone tissue in Oxys rats of different age. Material and Methods. Mineral density of bone tissue in Oxys and Wistar male rats at the age of 2–18 months was examined with x-ray bone densitometer LUNAR-Exert-XL (USA). Bone fragments of vertebral bodies and of forelegs and hind legs were studied by histomorphometric assay with software Motic Images Plus 2.0 ML (Micromed, Russia). Results. X-ray bone densitometry findings have shown that bone mineral density increase in Oxys rats does not attain the values shown by age-matched control rats, and progressively decreases after the age of 6 months. Data obtained by histomorphometric analysis of vertebral bodies and limbs have reliably demonstrated that there is a change in quantitative and qualitative bone tissue parameters of Oxys rats which is a characteristic of osteoporosis. Conclusion. Bone tissue changes in Oxys rats correspond to that observed in human osteoporosis, what allows to use rat as a model for the study of osteoporosis pathogenesis and for development of prophylaxis and treatment methods.

Bone and Lean Tissue Changes Following Cranial Cruciate Ligament Transection and Stifle Stabilization

Following cranial cruciate ligament transection and extracapsular stabilization, dual-energy X-ray absorptiometry was used to analyze bone mineral content and lean tissue mass in the surgical and nonsurgical legs (n=14) at 0, 2, 4, and 8 weeks, and to evaluate bone mineral content and bone mineral density (BMD) of the proximal, mid-, and distal tibia of both the surgical and nonsurgical legs (n=15) at 0, 5, and 10 weeks. There was significant loss of bone mineral content and lean tissue in the surgical leg compared to the nonsurgical leg. Significant loss in bone mineral content and BMD was detected in the tibia of the surgical leg and was most pronounced in the metaphyseal region.

Ação da atividade física sobre as propriedades mecânicas dos fêmures e tíbias de ratas osteopênicas

Avaliamos as propriedades mecânicas, obtidas através de ensaios de flexo-compressão de fêmures e de flexão em 3 pontos de tíbias, de ratas adultas, ovariectomizadas e submetidas à atividade física. Foram utilizadas 30 ratas divididas em 3 grupos: G1: Controle. G2: Animais ovariectomizados e não submetidos a exercícios. G3: Foram treinados em uma gaiola giratória por cinco dias consecutivos, em seguida submetidos à ovariectomia, permanecendo em repouso por 24 horas. Exercitaram por 30 minutos, 5 dias por semana durante 9 semanas com velocidade de aproximadamente 0,31 m/s. Os valores obtidos de carga e de deformação evidenciaram que os fêmures das ratas ovariectomizadas apresentaram redução estatisticamente significativa nas propriedades mecânicas de carga e de deformação no limite máximo. Os fêmures do grupo ovariectomizado e submetido à prática de exercícios apresentaram valores de carga e de deformação no limite máximo superiores aos do grupo apenas ovariectomizado, no entanto, sem significância estatística. As tíbias não apresentaram alterações significativas em nenhuma das propriedades mecânicas estudadas. A atividade física aplicada por 30 minutos, 5 dias por semana durante 9 semanas a 0,31 m/s não foi suficiente para corrigir as alterações biomecânicas do tecido ósseo provocadas pela ovariectomia.

Bone tissue changes in early-stage osteoarthritis of the human knee precede overlying cartilage damage

Bone tissue changes in early-stage osteoarthritis of the human knee precede overlying cartilage damage

Análise clínica, radiológica, macroscópica e histológica do úmero de codornas domésticas (Coturnix japonica), submetido ao implante da poliuretana derivada do polímero de mamona (Ricinnus communis)

Na cirurgia ortopédica, são freqüentes as situações em que o cirurgião se depara com grandes perdas ósseas, provocadas especialmente por traumatismos de alta energia, tumores ou infecções. A reparação dessas fraturas requer grande conhecimento a respeito de materiais que possam ser utilizados para preencher essas falhas. Esses materiais podem ser derivados biológicos, sintéticos ou metálicos. Dentre eles, destacam-se os enxertos ósseos e os implantes de biomateriais. Com o aumento dos animais exóticos, utilizados como animais de estimação, a casuística clínica e cirúrgica dessa especialidade vem crescendo, tanto em clínicas quanto em hospitais veterinários. Particularmente, as aves constituem a maioria desses animais, e entre seus problemas cirúrgicos as fraturas são os de maior destaque. O objetivo deste trabalho foi estudar o efeito clínico, radiológico, macroscópico e histológico da poliuretana derivada do polímero de mamona (Ricinnus communis) implantada no úmero de codornas domésticas (Coturnix japonica). Para isso, foram utilizadas 20 codornas, machos e fêmeas, separadas aleatoriamente em quatro grupos de cinco animais, os quais receberam o implante no úmero esquerdo, com exame clínico diário durante o período pós-operatório, avaliações radiológica imediata e quinzenal e macroscópica e histológica aos 15, 30, 60 e 90 dias. Clinicamente não foram observadas alterações locais, regionais nem sistêmicas. Ao exame radiológico, notou-se aumento de densidade local, sem sinais de alteração óssea, dos tecidos circunjacentes, e de sacos aéreos. A análise macroscópica revelou que a poliuretana de mamona não foi absorvida em nenhum dos quatro grupos permanecendo implantada no seio do osso pneumático, porém, notou-se alteração em sua resistência. O exame histopatológico mostra inicialmente mínima reação inflamatória, discreta fibrose ao redor do implante e osteointegração pela presença de trabéculas e medula óssea no interior do implante. Concluiu-se que a poliuretana derivada do polímero de mamona é biocompatível em aves, podendo ser utilizada na cirurgia ortopédica, ocorrendo osteointegração.

Dietary calcium and health

Dietary calcium and health

MTA and calcium hydroxide for pulp capping

This study evaluated the biocompatibility of mineral trioxide aggregate (MTA) after direct capping of exposed pulp tissue in dog's teeth. Class I cavities were prepared in 26 teeth from 3 adult dogs. MTA was applied over the exposed pulp in 13 teeth and paste of calcium hydroxide plus distilled water (control) was applied in the remaining 13 teeth. After 90 days, the animals were killed; the maxilla and mandible were dissected and sectioned to obtain individual roots. The samples were processed histologically. The pulp and periapical response observed with the use of MTA was similar to that of calcium hydroxide paste. In all specimens, there was a dentin bridge obliterating the exposure, an intact odontoblastic layer, no inflammatory cells, normal connective pulp tissue, normal apical and periapical regions and no bone tissue changes. Similar to calcium hydroxide, MTA presented excellent response when used for direct pulp capping.

IZMENENIYa KOSTNOY TKANI ChELOVEKA V KOSMIChESKOM POLETE II. NEKOTORYE ZAKONOMERNOSTI I OSOBENNOSTI

There are considered possible mechanisms of some peculiarities of cosmonauts bone tissue changes after space flights 5-7 month duration, that were diagnosed using dual energy X-ray absoptiometry (DEXA). Local osteopenia in spongy bone of the body lower part may be connected with big weight bearing load in 1g conditions. Increasing of mineral content in upper part of the skeleton and hypermineralization of vertebrae body spongy bone, that were showed by computer tomography possible are the secondary effects and are connected with fluid redistribution to cranial direction, including abdomen. Additional negative gradient of bone mass in bones of lower part of skeleton, that is observed in early period of readaptation (till 1 month) may be explained as result of acceleration of bone remodeling (resorption and formation of bone), as reaction to recover of loading. Individual variability of above mentioned reactions is connected with genetically determined initial bone mass and phenotype of bone metabolism. There are considered possibilities of genetic prediction of osteopenia in discussed conditions.

Infrared spectroscopic characterization of mineralized tissues

Vibrational spectroscopy (Infrared and Raman), and in particular micro-spectroscopy and micro-spectroscopic imaging has been used to characterize developmental changes in bone and other mineralized tissues, to monitor these changes in cell cultures, and to detect disease and drug-induced modifications. Examples of the use of infrared micro-spectroscopy and micro-spectroscopic imaging are discussed in this review.

The characterization of human cortical bone microdamage by nuclear magnetic resonance

A nuclear magnetic resonance (NMR) spin–spin (T2) relaxation technique has been described for detecting post-damage microstructural changes in human cortical bone tissue. The technique is applied to quantify apparent changes in bone porosity resulting from cyclic loading induced microdamage in cortical bone. Overall bone porosity is determined using the calibrated NMR fluid volume from the proton relaxation data divided by the overall bone volume. The NMR porosities obtained from cortical bone specimens pre- and post-damage are compared with the currently available but destructive histomorphometrically determined porosity. The advantages of using NMR T2 relaxation techniques for bone microdamage are illustrated. The T2 relaxation data can be inverted to T2 relaxation distribution. The inversion T2 relaxation distribution can then be transformed to a pore-size distribution with the longer relaxation times corresponding to larger pores if the surface relaxivity constant is known. It is shown that by using NMR 2 MHz or 27 MHz proton resonance, similar surface relaxivity constants are obtained. It is also demonstrated that the NMR T2 relaxation data are sensitive to changes resulting from the creation of microdamage in cortical bone, which can be interpreted as an effective increase in bone porosity. These results indicate that the detection of cortical bone microdamage is possible by this technique.

A New Approach to the Treatment of Osteoporosis

Osteoporosis remains a significant clinical problem despite the availability of effective therapies. The main therapy still needed is an anabolic agent for the treatment of osteoporosis. This study examined the in vivo effect of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor simvastatin, which controls the first step in the biosynthesis of cholesterol, on bone formation in rats. Histologic specimens were collected 7, 14, and 21 days after administration of 1 mg of simvastatin for 5 days and compared with control specimens for changes in bone tissue. The observed effects on the bone in a healthy animal model included advancement of the blood supply, acceleration of the proliferation and differentiation of osteoprogenitor cells, and formation of osteoid tissue.

Regulation of mineral-to-matrix ratio of lumbar trabecular bone in ovariectomized rats treated with risedronate in combination with or without vitamin K2.

The relationship between bone turnover and bone tissue and material properties was examined in ovariectomized (OVX) rats treated with risedronate in combination with or without vitamin K2. Seventy female rats, 18 weeks of age, were assigned to 7 groups (n=10): sham-operated + vehicle control; OVX + vehicle control; OVX + risedronate 0.1, 0.5, or 2.5 mg/kg/day po; OVX + vitamin K2 approximately 30 mg/kg/day po; OVX + vitamin K2 (approximately 30 mg/kg/day) and risedronate (0.5 mg/kg/day). Treatments were given daily for 9 months. To assess bone turnover, we measured serum osteocalcin and urinary deoxypyridinoline at 0, 3, and 9 months. To assess vertebral and femoral tissue and material properties, bone mass, bone mineral density (BMD by DXA), trabecular bone structure (vertebra: 3D-microCT), cortical bone structure (femur: histomorphometry), biomechanical properties, and mineral properties (mineral-to-matrix and carbonate-to-phosphate ratios by Fourier transform infrared microspectroscopy) were measured ex vivo at 9 months. Ovariectomy increased bone turnover and induced significant loss of bone mass/density, structure, mineral properties (mineral-to-matrix ratio), and strength. Risedronate produced dose-dependent inhibition of the ovariectomy-induced increase in turnover and loss of bone mass/density, structure, mineral-to-matrix ratio, and strength, with a lowest effective dose of 0.1-0.5 mg/kg/day. High-dose risedronate (2.5 mg/kg/day) did not induce increases in any parameter above that of sham control. Vitamin K2 had no effects. In the OVX groups, urinary deoxypyridinoline at 3 and 9 months correlated significantly with vertebral BMD, trabecular bone volume, ultimate load, stiffness, and mineral-to-matrix ratio, and with femoral BMD, cortical area, and ultimate load. These results support the concept that changes in bone tissue and material properties can result directly from changes in bone turnover. Different effects among different drugs on material properties, including mineral-to-matrix ratio, may reflect differences in the relative rate and magnitude of osteoclastic bone resorption and osteoblastic primary bone mineralization.

Congenital infiltrating lipomatosis of the face and neck

Congenital infiltrating lipomatosis is a rare clinicopathologic entity characterized by infiltrating lipomatous tumors which, although of benign nature, have a tendency to recur after surgery. This has a predilection for the extremities and the trunk and is seen as overgrowth of soft tissue and bone. It rarely affects the face and neck. We describe two cases of congenital infiltrating lipomatosis of face and neck depicting the bone and soft tissue changes seen on computed tomography, along with a review of the literature on the subject.

Recent developments in Raman and infrared spectroscopy and imaging of bone tissue

Vibrational spectroscopy is an important tool in mineralized tissue research. This review focuses on recent applications of Raman and IR spectroscopies as contrast enhancement agents, tools for studying the chemical nature of changes in bone tissue with age and disease and understanding the molecular nature of changes in bone tissue during mechanical loading and fracture.

Microfocus Computed Tomography Analysis of Early Changes in Bone Microstructure in Rats with Chronic Renal Failure

Background/Aims: Little is known about the microstructural changes in bone tissue in the early phase of chronic renal failure (CRF). In this study, we analyzed the bone tissue in a rat model of early CRF using a high-resolution X-ray tomographic system, i.e. microfocus computed tomography (MXCT), which is capable of detecting microscopic structural changes in bone tissue. Methods: CRF rats were created by 7/8 nephrectomy by ligation of the renal artery branches, and were sacrificed 24 weeks after surgery. MXCT and bone mineral densitometry by single-energy X-ray absorptiometry (SXA) were performed using extracted bone samples. Images obtained by MXCT were further analyzed by node-strut morphometry. Results: Biochemical analysis confirmed that CRF was induced in 7/8-renal artery-ligated rats. MXCT demonstrated a significant decrease in trabecular bone in uremic rats, whereas SXA was unable to detect the difference. The node-strut method revealed decreased trabecular connectivity, with little change in the thickness of the trabecular bone in uremic rats. Conclusion: MXCT was able to detect significant changes in trabecular bone at an early stage of renal failure. The observed structural changes differed from those found in long-term dialysis patients. MXCT is a practical and promising device used for the non-invasive evaluation of early bone changes in uremic patients.

Repetitive, negligible force reaching in rats induces pathological overloading of upper extremity bones.

Work-related repetitive motion disorders are costly. Immunohistochemical changes in bones resulting from repetitive reaching and grasping in 17 rats were examined. After 3-6 weeks, numbers of ED1+ macrophages and osteoclasts increased at periosteal surfaces of sites of muscle and interosseous membrane attachment and metaphyses of reach and nonreach forelimbs. These findings indicate pathological overloading leading to inflammation and subsequent bone resorption. Sixty-five percent of all occupational illnesses in U.S. private industry are attributed to musculoskeletal disorders arising from the performance of repeated motion, yet the precise mechanisms of tissue pathophysiology have yet to be determined for work-related musculoskeletal disorders. This study investigates changes in upper extremity bone tissues resulting from performance of a voluntary highly repetitive, negligible force reaching and grasping task in rats. Seventeen rats reached an average of 8.3 times/minute for 45-mg food pellets for 2 h/day, 3 days/week for up to 12 weeks. Seven rats served as normal or trained controls. Radius, ulna, humerus, and scapula were collected bilaterally as follows: radius and ulna at 0, 3, 4, 5, 6, and 12 weeks and humerus and scapula at 0, 4, and 6 weeks. Bones were examined for ED1-immunoreactive mononuclear cells and osteoclasts. Double-labeling immunohistochemistry was performed for ED1 (monocyte/macrophage lineage cell marker) and TRACP (osteoclast marker) to confirm that ED1+ multinucleated cells were osteoclasts. Differences in the number of ED1+ cells over time were analyzed by ANOVA. Between 3 and 6 weeks of task performance, the number of ED1+ mononuclear cells and osteoclasts increased significantly at the periosteal surfaces of the distal radius and ulna of the reach and nonreach limbs compared with control rats. These cells also increased at periosteal surfaces of humerus and scapula of both forelimbs by 4-6 weeks. These cellular increases were greatest at muscle attachments and metaphyseal regions, but they were also present at some interosseous membrane attachments. The number of ED1+ cells decreased to control levels in radius and ulna by 12 weeks. Increases in ED1+ mononuclear cells and osteoclasts indicate that highly repetitive, negligible force reaching causes pathological overloading of bone leading to inflammation and osteolysis of periosteal bone tissues.