The Role of Crystallographic Texture of Ti-6Al-4V Alloy on Cell Attachment and Proliferation

2005 ◽  
Vol 495-497 ◽  
pp. 705-710 ◽  
Author(s):  
S. Faghihi ◽  
M.R. Bateni ◽  
Fereshteh Azari ◽  
Jerzy A. Szpunar ◽  
H. Vali ◽  
...  
Keyword(s):  
Crystallographic Texture ◽  
Cell Attachment ◽  
Proliferation Rate ◽  
Osteoblastic Cell ◽  
X Ray Diffraction ◽  
Joint Replacements ◽  
In Vitro Systems ◽  
Cell Adhesion And Proliferation

Owing to their lower modulus, great corrosion resistance and superior biocompatibility, titanium alloys are increasingly used as artificial joint replacements. However bone bonding capability of these materials needs to be improved. Many studies are currently conducted to improve the osseo-integration of titanium based implants. In the present study, the role of crystallographic texture of titanium alloy Ti-6Al-4V on bone bonding capability was investigated in vitro systems. X-ray diffraction analysis was used to determine preferred orientation in each substrate. These substrates were seeded with preosteoblast cells to examine cell attachment and proliferation. Attachment of cells was assessed by counting the number of adhered cells within 30-240 min. The proliferation rate of cells was measured between the 3rd-11th days of incubation. The results suggest that the substrate with (100) orientation shows better osteoblastic cell adhesion and proliferation rate than the (110).

Effects of dietary alteration of bicarbonate and magnesium on rat bone

1986 ◽  
Vol 250 (2) ◽  
pp. F302-F307 ◽  
Author(s):  
J. M. Burnell ◽  
C. Liu ◽  
A. G. Miller ◽  
E. Teubner
Keyword(s):  
Crystal Structure ◽  
Bone Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growing Rats ◽  
Final Composition ◽  
Rat Bone

To study the effects of bicarbonate and magnesium on bone, mild acidosis and/or hypermagnesemia were produced in growing rats by feeding ammonium chloride and/or magnesium sulfate. Bone composition, quantitative histomorphometry, and mineral x-ray diffraction (XRD) characteristics were measured after 6 wk of treatment. The results demonstrated that both acidosis (decreased HCO3) and hypermagnesemia inhibited periosteal bone formation, and, when combined, results were summative; and the previously observed in vitro role of HCO3- and Mg2+ as inhibitors of crystal growth were confirmed in vivo. XRD measurements demonstrated that decreased plasma HCO3 resulted in larger crystals and increased Mg resulted in smaller crystals. However, the combined XRD effects of acidosis and hypermagnesemia resembled acidosis alone. It is postulated that the final composition and crystal structure of bone are strongly influenced by HCO3- and Mg2+, and the effects are mediated by the combined influence on both osteoblastic bone formation and the growth of hydroxyapatite.

The Role of Microbiology in Models of Dental Caries: Reaction Paper

1995 ◽  
Vol 9 (3) ◽  
pp. 255-269 ◽  
Author(s):  
G.H. Bowden
Keyword(s):  
Process Selection ◽  
Advantages And Disadvantages ◽  
Test Models ◽  
Plaque Development ◽  
In Vitro Systems ◽  
Selection Of

Models of the caries process have made significant contributions toward defining the roles of bacteria in caries. Microbiologists use a variety of in vitro systems to model aspects of the caries process. Also, in situ models in humans provide information on the microbiology of caries in vivo. These models do not involve the entire process leading to natural caries; consequently, the results from such studies are used to deduce the roles of bacteria in natural caries. Therefore, they can be described as Inferential Caries Models. In contrast, animal models and some clinical trials in humans involve natural caries and can be described as Complete Caries Models. Furthermore, these models are used in two distinct ways. They can be used as Exploratory Models to explore different aspects of the caries process, or as Test Models to determine the effects of anticaries agents. This dichotomy in approach to the use of caries models results in modification of the models to suit a particular role. For example, if we consider Exploratory Models, the in situ appliance in humans is superior to others for analyzing the microbiology of plaque development and demineralization in vivo. The chemostat and biofilm models are excellent for exploring factors influencing bacterial interactions. Both models can also be used as Test Models. The in situ model has been used to test the effects of fluoride on the microflora and demineralization, while the chemostat and biofilm models allow for the testing of antibacterial agents. Each model has its advantages and disadvantages and role in analysis of the caries process. Selection of the model depends on the scientific question posed and the limitations imposed by the conditions available for the study.

scholarly journals Dual Effects ofβ3Integrin Subunit Expression on Human Pancreatic Cancer Models

2010 ◽  
Vol 33 (5-6) ◽  
pp. 191-205 ◽  
Author(s):  
S. Marchán ◽  
S. Pérez-Torras ◽  
A. Vidal ◽  
J. Adan ◽  
F. Mitjans ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Rho Gtpases ◽  
Cell Attachment ◽  
Human Pancreatic Cancer ◽  
Cell Growth And Migration ◽  
Subunit Expression ◽  
And Migration

Background: Pancreatic cancer, the fifth leading cause of adult cancer death in Western countries, lacks early detection, and displays significant dissemination ability. Accumulating evidence shows that integrin-mediated cell attachment to the extracellular matrix induces phenotypes and signaling pathways that regulate tumor cell growth and migration.Methods: In view of these findings, we examined the role ofβ3in pancreatic cancer by generating two stableβ3-expressing pancreatic human cell lines and characterizing their behavior in vitro and in vivo.Results: Transduction ofβ3selectively augmented the functional membraneαvβ3integrin levels, as evident from the enhanced adhesion and migration abilities related to active Rho GTPases. No effects on in vitro anchorage-dependent growth, but higher anoikis were detected inβ3-overexpressing cells. Moreover, tumors expressingβ3displayed reduced growth. Interestingly, treatment of mice with anαv-blocking antibody inhibited the growth ofβ3-expressing tumors to a higher extent.Conclusion: Our results collectively support the hypothesis thatαvβ3integrin has dual actions depending on the cell environment, and provide additional evidence on the role of integrins in pancreatic cancer, which should eventually aid in improving prediction of the effects of therapies addressed to modulate integrin activities in these tumors.

scholarly journals Fretting and Fretting Corrosion Processes of Ti6Al4V Implant Alloy in Simulated Oral Cavity Environment

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1561
Author(s):  
Marcin Klekotka ◽  
Jan Ryszard Dąbrowski ◽  
Katarzyna Rećko
Keyword(s):  
Artificial Saliva ◽  
Open Circuit ◽  
Fretting Wear ◽  
Dissipated Energy ◽  
Titanium Oxides ◽  
X Ray Diffraction ◽  
Fretting Corrosion ◽  
Pin On Disc

The paper presents the results of in vitro studies of fretting and fretting corrosion processes of Ti6Al4V implant alloy in the environment of natural saliva and self-made mucin-based artificial saliva solutions. The study was performed on a specially designed fretting pin-on-disc tester, which was combined with a set used for electrochemical research. The open circuit potential measurements and potentiodynamic method were used for corrosion tests. The worn surfaces were subjected to microscopic observations and an evaluation of wear. Results were interpreted using the dissipated energy and third-body approaches. The X-ray diffraction analysis showed that titanium oxides constitute over 80% of the friction products. Special attention was paid to the role of saliva and its substitutes, which in certain cases can lead to the intensification of fretting wear. On the basis of the received results, a new phenomenological model of fretting corrosion processes was proposed. This model involves the formation of an abrasive paste that is a combination of metal oxides and the organic components of saliva.

Relaxation oscillator and core conductor models are needed for understanding of GI electrical activities

1994 ◽  
Vol 266 (3) ◽  
pp. G339-G349 ◽  
Author(s):  
E. E. Daniel ◽  
B. L. Bardakjian ◽  
J. D. Huizinga ◽  
N. E. Diamant
Keyword(s):  
Relaxation Oscillator ◽  
Pacesetter Potentials ◽  
In Vitro Systems ◽  
Cells Of Cajal ◽  
Electrical Activities ◽  
Core Conductor ◽  
Oscillator Models

This review examines the applicability of modeling of intestinal electrical activities (slow waves or pacesetter potentials) by coupled relaxation oscillator models, in comparison to a “multidimensional model” based on core conductor theory. We briefly review the relaxation oscillator model and correct some misunderstandings. We point out that new insights about the role of networks of interstitial cells of Cajal in intestinal pacemaking require reconsideration of the mechanisms producing oscillations, the coupling between oscillators, and how the oscillator network is coupled to the driven cells. Recent advances in relaxation oscillator models allow the production of pacemaking pacemaking activity, which can be selectively varied as to waveform, frequency, and occurrence of silent periods. Core conductor models do not produce pacemaking activity or permit this flexibility. We point out that many of the criticisms leveled against relaxation oscillator models relate to studies made in simplified in vitro systems constrained by extensive dissection. Such systems do not adequately reflect the in vivo systems. We conclude that a full understanding of control of electrical (and mechanical) events in the gastrointestinal tract requires that better understanding of relaxation oscillator models growing out of recent research be combined with improved applications of core conductor theory to multidimensional models.

Cytocompatibility Comparative Study of Hydroxyapatite Coating on Titanium Alloy Treated with Two Chemical Routes

2013 ◽  
Vol 658 ◽  
pp. 61-66
Author(s):  
Qing Zong Si ◽  
Xiao Li An ◽  
Yang Li ◽  
Bin Liu ◽  
Jin Qing Wang
Keyword(s):  
Titanium Alloy ◽  
In Vitro Cytotoxicity ◽  
Combination Method ◽  
Cytotoxicity Test ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Ha Coating ◽  
Cell Adhesion And Proliferation

In order to prepare bioactive hydroxyapatite (Ca10 (PO4)6(OH) 2, HA) coating with ideal biocompatibility, the surface of titanium alloy was treated with the two kinds of chemical methods, which are the acid-alkali-combination method and Self-polymerization-adhesion of dopamine. After pretreatment, the treated titanium alloy plates were immersed in simulated body fluid (SBF) to form HA coating on their surface. The chemical composition of the coating was analyzed by an X-ray diffraction (XRD) and the morphology was observed by a scanning electron microscope (SEM). After that, the plates were training in vitro cytotoxicity test with MC3T3-E1 osteoblasts. Compared with the results of cell culture, the method of Self- polymerization -adhesion of dopamine showed better cell adhesion and proliferation..

Challenges in simulating the human gut for understanding the role of the microbiota in obesity

2017 ◽  
Vol 8 (1) ◽  
pp. 31-53 ◽  
Author(s):  
M. Aguirre ◽  
K. Venema
Keyword(s):  
Potential Role ◽  
Human Gut ◽  
Colonic Fermentation ◽  
Physiological Relevance ◽  
In Vitro Simulation ◽  
In Vitro Systems ◽  
Specific Standard ◽  
Obese Subjects

There is an elevated incidence of cases of obesity worldwide. Therefore, the development of strategies to tackle this condition is of vital importance. This review focuses on the necessity of optimising in vitro systems to model human colonic fermentation in obese subjects. This may allow to increase the resolution and the physiological relevance of the information obtained from this type of studies when evaluating the potential role that the human gut microbiota plays in obesity. In light of the parameters that are currently used for the in vitro simulation of the human gut (which are mostly based on information derived from healthy subjects) and the possible difference with an obese condition, we propose to revise and improve specific standard operating procedures.

scholarly journals Engineering of Chitosan-Hydroxyapatite-Magnetite Hierarchical Scaffolds for Guided Bone Growth

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2321 ◽  
Author(s):  
Pistone ◽  
Celesti ◽  
Piperopoulos ◽  
Ashok ◽  
Cembran ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Bone Growth ◽  
Cell Attachment ◽  
X Ray Diffraction ◽  
Culture Studies ◽  
X Ray ◽  
Support Cell ◽  
Chitosan Matrix

Bioabsorbable materials have received increasing attention as innovative systems for the development of osteoconductive biomaterials for bone tissue engineering. In this paper, chitosan-based composites were synthesized adding hydroxyapatite and/or magnetite in a chitosan matrix by in situ precipitation technique. Composites were characterized by optical and electron microscopy, thermogravimetric analyses (TGA), x-ray diffraction (XRD), and in vitro cell culture studies. Hydroxyapatite and magnetite were found to be homogeneously dispersed in the chitosan matrix and the composites showed superior biocompatibility and the ability to support cell attachment and proliferation; in particular, the chitosan/hydroxyapatite/magnetite composite (CS/HA/MGN) demonstrated superior bioactivity with respect to pure chitosan (CS) and to the chitosan/hydroxyapatite (CS/HA) scaffolds

A crucial role of β1 integrins for keratinocyte migration in vitro and during cutaneous wound repair

Development ◽  
2002 ◽  
Vol 129 (9) ◽  
pp. 2303-2315 ◽  
Author(s):  
Richard Grose ◽  
Caroline Hutter ◽  
Wilhelm Bloch ◽  
Irmgard Thorey ◽  
Fiona M. Watt ◽  
...  
Keyword(s):  
Crucial Role ◽  
Wound Repair ◽  
Proliferation Rate ◽  
Cutaneous Wound ◽  
Keratinocyte Migration ◽  
Β1 Integrins ◽  
Cell Matrix Interactions

Integrins are ubiquitous transmembrane receptors that play crucial roles in cell-cell and cell-matrix interactions. In this study, we have determined the effects of the loss of β1 integrins in keratinocytes in vitro and during cutaneous wound repair. Flow cytometry of cultured β1-deficient keratinocytes confirmed the absence of β1 integrins and showed downregulation of α6β4 but not of αv integrins. β1-null keratinocytes were characterised by poor adhesion to various substrates, by a reduced proliferation rate and by a strongly impaired migratory capacity. In vivo, the loss of β1 integrins in keratinocytes caused a severe defect in wound healing. β1-null keratinocytes showed impaired migration and were more densely packed in the hyperproliferative epithelium. Surprisingly, their proliferation rate was not reduced in early wounds and even increased in late wounds. The failure in re-epithelialisation resulted in a prolonged inflammatory response, leading to dramatic alterations in the expression of important wound-regulated genes. Ultimately, β1-deficient epidermis did cover the wound bed, but the epithelial architecture was abnormal. These findings demonstrate a crucial role of β1 integrins in keratinocyte migration and wound re-epithelialisation. Movies available on-line

Effects of testicular interstitial fluid on the proliferation of the mouse spermatogonial stem cells in vitro

Zygote ◽  
2013 ◽  
Vol 22 (3) ◽  
pp. 395-403 ◽  
Author(s):  
Peng Wang ◽  
Yi Zheng ◽  
Ying Li ◽  
Hua Shang ◽  
Guang-Xuan Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Interstitial Fluid ◽  
Culture Medium ◽  
Physiological Role ◽  
Spermatogonial Stem Cells ◽  
Proliferation Rate ◽  
Pcr Analysis ◽  
Polymerase Chain

SummarySpermatogenesis is a process in adult male mammals supported by spermatogonial stem cells (SSCs). The cultivation of SSCs has potential value, for example for the treatment of male infertility or spermatogonial transplantation. Testicular interstitial fluid was added to culture medium to a final concentration of 5, 10, 20, 30 or 40%, in order to investigate its effects on proliferation of mouse SSCs in vitro, Alkaline phosphatase (AKP) assay, reverse transcription polymerase chain reaction (RT-PCR) analysis and indirect immunofluorescence of cells were performed to identify SSCs, and the proliferation rate and diameters of the SSCs colonies were measured. The results showed that the optimal addition of testicular interstitial fluid to culture medium was 30%. When medium supplemented with 30% testicular interstitial fluid was used to culture mouse SSCs, the optimum proliferation rate and diameter of the cell colonies were 72.53% and 249 μm, respectively, after 8 days in culture, values that were significant higher than those found for other groups (P < 0.05). In conclusion, proliferation of mouse SSCs could be promoted significantly by supplementation of the culture medium with 30% testicular interstitial fluid. More research is needed to evaluate and understand the precise physiological role of testicular interstitial fluid during cultivation of SSCs.

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