Changes In Bone Tissue Research Articles

Dega osteotomy for the treatment of developmental dysplasia of the hip

Background The neglected developmental dysplasia of the hip with adaptive changes in bone and soft tissue is difficult to treat. Dega osteotomy is added to open reduction to confer concentric stable reduction with good coverage of the head of the femur. Patients and methods Forty hips in 32 patients were treated using open reduction and Dega osteotomy. There were 30 dislocated and 10 subluxated hips according to Tonnis grading. Radiographic parameters used in this study included the acetabular index, the acetabular angle of sharp, the caput-collum-diaphyseal angle, and the center-edge angle of Wiberg; the final radiographic outcome was evaluated according to the Severin classification. Clinical results were evaluated according to the modified McKay criteria. Results The mean follow-up period was 96 months. The final results according to Barrett’s modification of McKay’s criteria were as follows: 34 (85%) with favorable results and 6 (15%) hips with unfavorable results. According to the Severin criteria for the evaluation of radiographic results, 74% were types I and II whereas 26% showed types III and IV; no hips were rated as Severin’s groups V or VI. Eight (33.4%) hips in children with unilateral involvement had developed coxa magna, but in no case did this interfere with hip concentricity. Three hips showed avascular necrosis on the latest radiographs. Conclusion The Dega osteotomy added to the open reduction, capsulorrhaphy, and femoral shortening is a safe, simple, and adequate procedure for the management of neglected developmental dysplasia of the hip patients after 2 years of age, with lower complication rates. Restoring the acetabulum to normal or nearly normal can result in good long-term results.

Clinical relevance of dimensional bone and soft tissue alterations post‐extraction in esthetic sites

The key to achieving pleasing esthetics in implant dentistry is a thorough understanding of the biological processes driving dimensional bone and soft tissue alterations post-extraction. The aim of the present report is first to characterize the extent of bone and soft tissue changes post-extraction and second to identify potential factors influencing tissue preservation in order to facilitate successful treatment outcomes. The facial bone wall thickness has been identified as the most critical factor influencing bone resorption and can be used as a prognostic tool in order to identify sites at risk for future facial bone loss subsequent to tooth extraction. Clinical studies indicated that thin bone wall phenotypes exhibiting a facial bone wall thickness of 1mm or less revealed progressive bone resorption with a vertical loss of 7.5mm, whereas thick bone wall phenotypes showed only minor bone resorption with a vertical loss of 1.1mm. This is in contrast to the dimensional soft tissue alterations. Thin bone wall phenotypes revealed a spontaneous soft tissue thickening after flapless extraction by a factor of seven, whereas thick bone wall phenotypes showed no significant changes in the soft tissue dimensions after 8weeks of healing. In sites exhibiting a limited bone resorption rate, immediate implant placement may be considered. If such ideal conditions are not present, other timing protocols are recommended to achieve predictable and pleasing esthetics. Socket preservation techniques for ridge preservation utilizing different biomaterials and/or barrier membranes often result in a better maintenance of tissue volumes, although the inevitable biological process of post-extraction bone resorption and bone modeling cannot be arrested. In summary, the knowledge of the biological events driving dimensional tissue alterations post-extraction should be integrated into the comprehensive treatment plan in order to limit tissue loss and to maximize esthetic outcomes.

Dimensional changes of hard and soft tissue after immediate implantation in comparison with conventional tooth extraction

Introduction: Immediate implantation in single-root teeth has been claimed to possess some benefits, especially bone preservation. The aim of this study was to evaluate ridge changes after immediate implantation in comparison with tooth extraction and dental socket healing.Methods and Materials: In this study, 21 patients with hopeless single-root teeth were selected. After impression and cast making, the patients were divided into test and control groups. Each group included twelve dental sockets. For all teeth the extraction was performed atraumatically. Measurements included bucco-lingual ridge dimensions at 3mm and 7mm apical to an imaginary line connecting the CEJs of the two adjacent teeth (CEJ line) as well as vertical distance between the mentioned line and bone crest at the misobuccal, midbuccal, distobuccal, mesiopalatal, midpalatal, and distopalatal aspects. In addition, soft tissue measurements similar to hard tissue ones were taken using stone casts and acrylic stents. In test group immediate implantation was carried out following extraction whereas in the control group dental sockets were left for natural healing. Four months after the operation, in both groups, the flap was reflected and measurements taken at baseline were repeated.Results: Vertical changes of soft tissues in test group were significantly less than control group at all points except in mid-buccal aspect (p=0.033 for mesiobuccal, p=0.026 for distobuccal, p=0.004 for midpalatal, p=0.002 mesiopalatal, p=0.022 for distopalatal, p=0.016 for distal, p=0.048 for mesial). Horizontal dimension change of soft tissue at 7mm apical to the CEJ line in test group, were also significantly less than control group (p= 0.051). Vertical changes of hard tissue, measured in all points, in test group were less than those of control group. These changes were significant in mid-buccal, mid-palatal, mesiopalatal and distopalatal points (p= 0.046, 0.029, 0.020 and 0.026 respectively). Horizontal changes of hard tissue at 3mm and 7mm apical to the CEJ line in test group were also less than control group. However, this was significant only at the 3mm point (p=0.028).Conclusion: According to the results of this study, it can be concluded that immediate implantation is to some extent effective in reducing the expected vertical and horizontal bone and soft tissue changes occurring following conventional tooth extraction and natural socket healing. Further investigation is warranted to determine the optimum method of preventing these changes.Bangladesh Journal of Medical Science Vol.15(3) 2016 p.335-342

The Influence of Hindlimb Unloading on Bone and Muscle Tissues in Rat Model

Numerous results indicate on interactions between muscles and bones. Thus, mechanical, genetic, endocrine, and age-related factors influence both tissues at the same time. Nevertheless, the details of physiological mechanisms of interaction between muscles and bones are still unclear. The purpose of this study was to evaluate the changes in low extremity muscles and bones during gravitational hindlimb unloading in rats. After hindlimb unloading during 7, 14, 21, and 30 days, muscles from the low extremities were collected and measured to estimate the muscle weight and perform cross-sectional analysis. Femoral bones were collected in order to evaluate weight, density, and geometrical parameters of the bone. Additionally, a test with a three-point bending was carried out to evaluate biomechanical bone properties. Results show that loss of muscle weight can be observed already at 1 week of hindlimb unloading with the maximum changes at 14 days. Changes in bone tissue showed the maximum loss of bone weight at 21 day. By 30 days of unloading, the density and rigidity of a bone were decreased; however, the most profound changes were observed in reduction of bone durability. These data support a hypothesis that the atrophy of skeletal muscles may promote the subsequent bone deterioration.

IL-6 Contributes to the Defective Osteogenesis of Bone Marrow Stromal Cells from the Vertebral Body of the Glucocorticoid-Induced Osteoporotic Mouse.

Osteoporosis is one of the most prevalent skeletal system diseases. It is characterized by a decrease in bone mass and microarchitectural changes in bone tissue that lead to an attenuation of bone resistance and susceptibility to fracture. Vertebral fracture is by far the most prevalent osteoporotic fracture. In the musculoskeletal system, osteoblasts, originated from bone marrow stromal cells (BMSC), are responsible for osteoid synthesis and mineralization. In osteoporosis, BMSC osteogenic differentiation is defective. However, to date, what leads to the defective BMSC osteogenesis in osteoporosis remains an open question. In the current study, we made attempts to answer this question. A mouse model of glucocorticoid-induced osteoporosis (GIO) was established and BMSC were isolated from vertebral body. The impairment of osteogenesis was observed in BMSC of osteoporotic vertebral body. The expression profiles of thirty-six factors, which play important roles in bone metabolisms, were compared through antibody array between normal and osteoporotic BMSC. Significantly higher secretion level of IL-6 was observed in osteoporotic BMSCs compared with normal control. We provided evidences that IL-6 over-secretion impaired osteogenesis of osteoporotic BMSC. Further, it was observed that β-catenin activity was inhibited in response to IL-6 over-secretion. More importantly, in vivo administration of IL-6 neutralizing antibody was found to be helpful to rescue the osteoporotic phenotype of mouse vertebral body. Our study provides a deeper insight into the pathophysiology of osteoporosis and identifies IL-6 as a promising target for osteoporosis therapy.

Chronic effects of soft drink consumption on the health state of Wistar rats: A biochemical, genetic and histopathological study.

The present study was performed to examine the effects of chronic soft drink consumption (SDC) on oxidative stress, biochemical alterations, gene biomarkers and histopathology of bone, liver and kidney. Free drinking water of adult male Wistar rats was substituted with three different soft drinks: Coca-Cola, Pepsi and 7-Up, for three consecutive months. The serum and organs were collected for examining the biochemical parameters associated with bone, liver and kidney functions. Semi-quantitative reverse transcription polymerase chain reaction was used to observe the changes in the expression of genes in the liver and kidney, which are associated with oxidative stress resistance. Histopathological investigations were performed to determine the changes in bone, liver and kidney tissues using hematoxylin and eosin stains. SDC affected liver, kidney and bone function biomarkers. Soft drinks increased oxidative stress, which is represented by an increase in malondialdehyde and a decrease in antioxidant levels. SDC affected serum mineral levels, particularly calcium and phosphorus. Soft drinks downregulated the expression levels of glutathione-S-transferase and super oxide dismutase in the liver compared with that of control rats. Rats administered Coca-Cola exhibited a hepatic decrease in the mRNA expression of α2-macroglobulin compared with rats administered Pepsi and 7-Up. On the other hand, SDC increased the mRNA expression of α1-acid glycoprotein. The present renal studies revealed that Coca-Cola increased the mRNA expression levels of desmin, angiotensinogen and angiotensinogen receptor compared with the other groups, together with mild congestion in renal histopathology. Deleterious histopathological changes were reported predominantly in the bone and liver of the Coca-Cola and Pepsi groups. In conclusion, a very strict caution must be considered with SDC due to the increase in oxidative stress biomarkers and disruption in the expression of certain genes associated with the bio-vital function of both the liver and kidney.

Osteoporosis and pain severity in reproductive age patients with breast cancer

Aim. To analyze the relationship of osteoporosis in reproductive age patients with breast cancer with the pain severity and osteoporosis diagnosis improvement in these patients to improve their quality of life.Methods. The study included 63 women aged 30 to 50 years. The studied group consisted of 33 women with confirmed diagnosis of breast cancer, control group - 30 healthy, same age women of comparison group. The examination included a blood test for osteocalcin, calcitonin, alkaline phosphatase, parathyroid hormone, thyroid stimulating hormone, calcium and phosphorus. The pain severity was evaluated by McGill pain questionnaire and pain syndrome classification. Osteodensitometry was performed to all patients of studied and control groups. All patients with «breast cancer» diagnosis were examined prior to specific treatment administration and 6 months after treatment course completion. 12 patients were examined also after neoadjuvant chemotherapy.Results.Osteopenia (initial changes of bone tissue) was revealed in 3 (10%) cases in the control group. There was no cases of osteoporosis in the control group. Clinical manifestations in the form of the 1st level pain syndrome in healthy women was registered in 6 (20%) cases. Osteoporosis develops more often in patients who underwent complex treatment with ovarian function blocking, i.e. the artificial menopause advent. Osteoporosis in breast cancer patients after combined treatment was detected in 69.7% of cases, and pain - in 75.8% of cases. Bone mineral density indicators during treatment and after it were significantly different compared to those before treatment (pConclusion. In breast cancer in reproductive age patients after the complex treatment, osteoporosis and pain often develop, therefore such patients need to undergo osteodensitometry for timely osteoporosis diagnosis and treatment correction.

Finite element analysis of osteoporosis models based on synchrotron radiation

With growing pressure of social aging, China has to face the increasing population of osteoporosis patients as well as the whole world. Recently synchrotron radiation has become an essential tool for biomedical exploration with advantage of high resolution and high stability. In order to study characteristic changes in different stages of primary osteoporosis, this research focused on the different periods of osteoporosis of rats based on synchrotron radiation. Both bone histomorphometry analysis and finite element analysis were then carried on according to the reconstructed three dimensional models. Finally, the changes of bone tissue in different periods were compared quantitatively. Histomorphometry analysis showed that the structure of the trabecular in osteoporosis degraded as the bone volume decreased. For femurs, the bone volume fraction (Bone volume/ Total volume, BV/TV) decreased from 69% to 43%. That led to the increase of the thickness of trabecular separation (from 45.05μ m to 97.09μ m) and the reduction of the number of trabecular (from 7.99 mm-1 to 5.97mm-1). Simulation of various mechanical tests with finite element analysis (FEA) indicated that, with the exacerbation of osteoporosis, the bones' ability of resistance to compression, bending and torsion gradually became weaker. The compression stiffness of femurs decreased from 1770.96 Fμ m−1 to 697.41 Fμ m−1, the bending and torsion stiffness were from 1390.80 Fμ m−1 to 566.11 Fμ m−1 and from 2957.28N.m/̂ to 691.31 N.m/̂ respectively, indicated the decrease of bone strength, and it matched the histomorphometry analysis. This study suggested that FEA and synchrotron radiation were excellent methods for analysing bone strength conbined with histomorphometry analysis.

Spinal Osteoid Osteoma Associated With Soft Tissue Changes as a Challenging Diagnosis: A Review of the Literature

Context: Spinal osteoid osteoma (OO) is an infrequent tumor and due to both its smallness and complex anatomy of the spine diagnosis is challenging. In addition, associated undefined soft tissue changes on magnetic resonance imaging (MRI) frequently cause misdiagnosis. Evidence Acquisition: PubMed database was searched for “spinal osteoid osteoma” and larger clinical series related to clinical pictures, diagnosis or treatment modalities, and also case reports with especially soft tissue changes and related to special treatment modalities were introduced to the study. It was aimed at to make conscious practitioners of clinical and diagnostic characteristics of spinal OOs. Results: Spinal OOs constitute about 10% of OOs and the most of the tumors are seen in adolescents or young adults. The most frequent clinical picture is painful scoliosis or torticollis according to the level of the tumor. On MRI that is the most frequently performed imaging modality in the patients with painful scoliosis, undefined extensive bone and soft tissue changes is quite frequent. Clinicians must be aware from these findings and they must suspect and investigate the patients with bone scintigraphy and thin sectioned computerized tomography that both of them together can show presence of the lesion and provide to determine exact location of the lesion. Despite the increasing number of the studies using percutaneous ablation techniques, standard treatment of spinal OOs is still intralesional excision. Surgical excision usually provides immediate pain relief, and recurrence is not frequent. Conclusions: Diffuse paravertebral muscle and soft tissue involvement having resemblance to myositis is not quite rare in the patients with spinal OO. This may be the sole finding on MRI and it must be alert for the clinicians to look for small OO nidus by bone scintigraphy or thin sectioned CT scan.

Cortical bone histomorphology of known-age skeletons from the Kirsten collection, Stellenbosch university, South Africa.

ABSTRACTObjectivesNormal human bone tissue changes predictably as adults get older, but substantial variability in pattern and pace remains unexplained. Information is needed regarding the characteristics of histological variables across diverse human populations.MethodsUndecalcified thin sections from mid‐thoracic ribs of 213 skeletons (138 M, 75 F, 17–82 years, mean age 48 years), are used to explore the efficacy of an established age‐at‐death estimation method and methodological approach (Cho et al.: J Forensic Sci 47 (2002) 12‐18) and expand on it. The ribs are an age‐balanced sample taken from skeletonized cadavers collected from 1967 to 1999 in South Africa, each with recorded sex, age, cause of death and government‐defined population group (129 “Colored,” 49 “Black,” 35 “White”).ResultsThe Ethnicity Unknown equation performs better than those developed for European‐Americans and African‐Americans, in terms of accuracy and bias. A new equation based solely on the study sample does not improve accuracy. Osteon population densities (OPD) show predicted values, yet secondary osteon areas (On.Ar) are smaller than expected for non‐Black subgroups. Relative cortical area (Ct.Ar/Tt.Ar) is low among non‐Whites.ConclusionsResults from this highly diverse sample show that population‐specific equations do not increase estimate precision. While within the published range of error for the method (±24.44 years), results demonstrate a systematic under‐aging of young adults and over‐aging of older adults. The regression approach is inappropriate. The field needs fresh approaches to statistical treatment and to factors behind cortical bone remodeling. Am J Phys Anthropol 160:137–147, 2016. © 2016 The Authors American Journal of Physical Anthropology Published by Wiley Periodicals, Inc.

EXPERIMENTAL PROPHYLACTIC REINFORCEMENT OF THE PROXIMAL FEMUR IN SYSTEMIC OSTEOPOROSIS: GENERAL PROBLEMS AND CONTRADICTIONS IN ORTHOPEDIC PRACTICE

The paper deals with an experimental study of prophylactic reinforcement of the proximal femur in old patients suffering from various diseases that induce destructive and dystrophic changes in bone tissue and cause pathological fractures. The authors have developed a prophylactic reinforcement procedure and created the designs of original implants for its performance with the patents of the Russian Federation having been obtained. The performed mathematical modeling and bed tests of the strength of a reinforced bone-implant system prove the increased strength of the proximal femur by 23–93% and lower the risk of fracture in the occurrence of low-energy injury.

Magnetic Resonance Imaging of Postoperative Fracture Healing Process without Metal Artifact: A Preliminary Report of a Novel Animal Model.

Background. Early radiological diagnosis and continual monitoring are of ultimate importance for timely treatment of delayed union, nonunion, and infection after bone fracture surgery. Although magnetic resonance imaging (MRI) could provide superior detailed images compared with X-ray and computed tomography (CT) without ionizing radiation, metal implants used for fracture fixation lead to abundant artifacts on MRI and thus prohibit accurate interpretation. The authors develop a novel intramedullary fixation model of rat femoral fracture using polyetheretherketone (PEEK) threaded rods and investigate its feasibility for in vivo MRI monitoring of the fracture healing process without artifact. Methods. Femoral fractures of 3 adult male Sprague-Dawley rats were fixed with intramedullary PEEK threaded rods. X-ray and MRI examinations were performed at day 7 postoperatively. Radiological images were analyzed for the existence of artifact interruption and postoperative changes in bone and peripheral soft tissue. Results. Postoperative plain film revealed no loss of reduction. MRI images illustrated the whole length of femur and peripheral tissue without artifact interruption, and the cortical bone, implanted PEEK rod, and soft tissue were clearly illustrated. Conclusion. This preliminary study introduced a novel rat model for in vivo MRI monitoring of the fracture healing process without metal artifact, by using intramedullary fixation of femur with PEEK threaded rod.

CALCIUM AND PHOSPHORUS CONTENT OF THE COMPACT BONE IN RATS WITH ALLOXAN DIABETES

Introduction: Most of the socio-economic importance of diabetes is an early disability of patients suffering from it. Among the chronic complications of diabetes, there are also abnormal changes in bone tissue. Aim: The aim of our work was to study the changes in the amount of calcium and phosphorus (the main inorganic constituents of bone) in a compact bone tissue in alloxan-induced diabetes in rats at different stages of the disease. Materials and Methods: The experiment was conducted on 70 white mongrel male rats weighing 180 to 220 g. Using the method of atomic emission spectroscopy with inductively coupled plasma we determined the content of calcium and phosphorus in the samples - femoral shafts weighting 5 mg. In homogenates of samples, we determined the activity of alkaline phosphatase. The entire list of measurements was repeated at 7, 14, 21 and 28 days of experiment. Results: The work revealed the decreases in the content of calcium at 7, 14 and 28 days of observation and phosphorus throughout the experiment with maximum changes on the 7th day of the experiment: 25% (p = 0.00002) and 15% (p = 0.002), respectively, compared with control values (median: 1.9 mg -calcium, 0.73 mg - phosphorus). There was a strong direct correlation between calcium and phosphorus (r = 0.086; p <0.01) and an inhibition of activity of alkaline phosphatase on day 28 of the experiment. Conclusions: For the first time, we show that alloxan diabetes in rats is accompanied by a decrease in phosphorus and calcium content of the compact bone with a maximum change at day 7 of the experiment. There are phase changes in the activity of alkaline phosphatase characterized by an increase at day 7 and inhibition by day 28 of the experiment.

Mid-Infrared Spectroscopy Analysis of the Effects of Erbium, Chromium:Yattrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) Laser Irradiation on Bone Mineral and Organic Components.

The effects of varying the energy density of a high-intensity erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser on the mineral and organic components of bone tissue were evaluated using Fourier transform infrared spectroscopy. Bone samples obtained from the tibias of rabbits were irradiated with five energy densities (3, 6, 8, 12, and 15 J/cm(2)), and the effects on the carbonate to phosphate ratio and in the organic components were compared with those of nonirradiated samples. The increased temperature during the laser irradiation was also measured using infrared thermography to relate the observed spectral changes to the laser thermal effects. The analyses of the infrared spectra suggests that the irradiation with Er,Cr:YSGG promoted changes in bone tissue in both the mineral and organic components that depend on the laser energy density, pointing to the importance of using the proper energy density in clinical procedures.

Early Effects of Single and Low-Frequency Repeated Administration of Teriparatide, hPTH(1-34), on Bone Formation and Resorption in Ovariectomized Rats.

Intermittent repeated administration of teriparatide (TPTD) has potent anabolic effects on bones in vivo. However, TPTD has both anabolic and catabolic effects on osteoblasts in vitro, and the mechanisms underlying its promotion of bone formation are unclear. This study aimed to elucidate the time-dependent changes in bone formation and resorption by examining changes in bone turnover markers and bone tissue over time after TPTD administration with low frequency in ovariectomized rats. The amount of serum osteocalcin, a bone formation marker, was transiently reduced after single TPTD administration, but increased thereafter, remaining increased for several days. In contrast, the amount of excreted urinary C-telopeptide, a bone resorption marker, increased transiently after single TPTD administration, and subsequently returned to control levels on the day after administration. Tissue histomorphometric analyses conducted 8 h after administration showed no changes in bone formation or bone resorption parameters. However, at 48 h, the bone formation parameters OS/BS and Ob.S/BS were increased, while the bone resorption parameter ES/BS was decreased. After repeated TPTD administration for 4 weeks, OS/BS, Ob.S/BS, and MS/BS increased, while Oc.S/BS decreased. Serum osteocalcin at 4 weeks after repeated administration was significantly correlated with OS/BS and Ob.S/BS. These present findings indicate that TPTD has dual, time-dependent effects on bone resorption and bone formation. Immediately after single administration, there was transient promotion of bone resorption and suppression of bone formation. However, sustained stimulation of bone formation occurred thereafter. Furthermore, these data suggest that this sustained bone formation led to anabolic effects with repeated TPTD administration.

Bone and Soft Tissue Changes after Two-Jaw Surgery in Cleft Patients.

BackgroundOrthognathic surgery is required in 25% to 35% of patients with a cleft lip and palate, for whom functional recovery and aesthetic improvement after surgery are important. The aim of this study was to examine maxillary and mandibular changes, along with concomitant soft tissue changes, in cleft patients who underwent LeFort I osteotomy and sagittal split ramus osteotomy (two-jaw surgery).MethodsTwenty-eight cleft patients who underwent two-jaw surgery between August 2008 and November 2013 were included. Cephalometric analysis was conducted before and after surgery. Preoperative and postoperative measurements of the bone and soft tissue were compared.ResultsThe mean horizontal advancement of the maxilla (point A) was 6.12 mm, while that of the mandible (point B) was -5.19 mm. The mean point A-nasion-point B angle was -4.1° before surgery, and increased to 2.5° after surgery. The mean nasolabial angle was 72.7° before surgery, and increased to 88.7° after surgery. The mean minimal distance between Rickett's E-line and the upper lip was 6.52 mm before surgery and 1.81 mm after surgery. The ratio of soft tissue change to bone change was 0.55 between point A and point A' and 0.93 between point B and point B'.ConclusionsPatients with cleft lip and palate who underwent two-jaw surgery showed optimal soft tissue changes. The position of the soft tissue (point A') was shifted by a distance equal to 55% of the change in the maxillary bone. Therefore, bone surgery without soft tissue correction can achieve good aesthetic results.

Mechanisms of morphogenetic disorders in the lower jaw under the influence of heavy metal salts on the body.

In the experiment on the 36 mature rats, the peculiarities of morphological disorders in the lower jaw of rats under the influence of salts of chromium, lead, zinc, iron, copper, and manganese are showed. Profound morphological changes in bone and cartilaginous tissues of lower jaw are followed by disorders of bone mineral content. The importance of the S100 protein in morphological changes in bone and cartilaginous tissues under the influence of heavy metal salts is shown.

Monochromatic computed microtomography using laboratory and synchrotron sources and X-ray fluorescence analysis for comprehensive analysis of structural changes in bones.

A combination of X-ray tomography at different wavelengths and X-ray fluorescence analysis was applied in the study of two types of bone tissue changes: prolonged presence in microgravity conditions and age-related bone growth. The proximal tail vertebrae of geckos were selected for investigation because they do not bear the supporting load in locomotion, which allows them to be considered as an independent indicator of gravitational influence. For the vertebrae of geckos no significant differences were revealed in the elemental composition of the flight samples and the synchronous control samples. In addition, the gecko bone tissue samples from the jaw apparatus, spine and shoulder girdle were measured. The dynamics of structural changes in the bone tissue growth was studied using samples of a human fetal hand. The hands of human fetuses of 11-15 weeks were studied. Autonomous zones of calcium accumulation were found not only in individual fingers but in each of the investigated phalanges. The results obtained are discussed.

Effect of higher frequency components and duration of vibration on bone tissue alterations in the rat-tail model

To formulate more accurate guidelines for musculoskeletal disorders (MSD) linked to Hand-Arm Vibration Syndrome (HAVS), delineation of the response of bone tissue under different frequencies and duration of vibration needs elucidation. Rat-tails were vibrated at 125 Hz (9 rats) and 250 Hz (9 rats), at 49 m/s2, for 1D (6 rats), 5D (6 rats) and 20D (6 rats); D=days (4 h/d). Rats in the control group (6 rats for the vibration groups; 2 each for 1D, 5D, and 20D) were left in their cages, without being subjected to any vibration. Structural and biochemical damages were quantified using empty lacunae count and nitrotyrosine signal-intensity, respectively. One-way repeated-measure mixed-model ANOVA at p<0.05 level of significance was used for analysis. In the cortical bone, structural damage quantified through empty lacunae count was significant (p<0.05) at 250 Hz (10.82 ± 0.66) in comparison to the control group (7.41 ± 0.76). The biochemical damage was significant (p<0.05) at both the 125 Hz and 250 Hz vibration frequencies. The structural damage was significant (p<0.05) at 5D for cortical bone while the trabecular bone showed significant (p<0.05) damage at 20D time point. Further, the biochemical damage increased with increase in the duration of vibration with a significant (p<0.05) damage observed at 20D time point and a near significant change (p=0.08) observed at 5D time point. Structural and biochemical changes in bone tissue are dependent upon higher vibration frequencies of 125 Hz, 250 Hz and the duration of vibration (5D, 20D).

Effects of fluoride on the ultrastructure and expression of Type I collagen in rat hard tissue

Long-term excessive fluoride (F) intake disrupts the balance of bone deposition and remodeling activities and is linked to skeletal fluorosis. Type I collagen, which is responsible for bone stability and cell biological functions, can be damaged by excessive F ingestion. In this study, Sodium fluoride (NaF) was orally administrated to rat at 150mgL−1 for 60 and 120d. We examined the effects of excessive F ingestion on the ultrastructure and collagen morphology of bone in rats by using transmission electron microscopy (TEM). Furthermore, we investigated the effect of F consumption on the expression levels of COL1A1 and COL1A2 in the bone tissues of rats by using quantitative real time (qRT)-PCR, to elucidate the molecular mechanisms of F-induced collagen protein damage. Our results showed that F affected collagen I arrangement and produced ultrastructural changes in bone tissue. Meanwhile, the mRNA expression of COL1A1 and COL1A2 were reduced and the COL I protein levels decreased in the fluorosis group. We concluded that excessive F ingestion adversely affected collagen I arrangement and caused ultrastructural changes in bone tissue. Reduced COL1A1 mRNA expression and altered COL I protein levels may contribute to the skeletal damage resulting from F exposure.