scholarly journals The Effect of Ca on In Vitro Behavior of Biodegradable Zn-Fe Alloy in Simulated Physiological Environments

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1624
Author(s):  
Orit Avior ◽  
Noa Ben Ghedalia-Peled ◽  
Tomer Ron ◽  
Razi Vago ◽  
Eli Aghion
Keyword(s):  
Corrosion Rate ◽  
Metabolic Activity ◽  
Electrochemical Analysis ◽  
Open Circuit ◽  
Hydrogen Gas ◽  
Hardness Tests ◽  
Fe Alloys ◽  
Cytotoxicity Assessment

The growing interest in Zn based alloys as structural materials for biodegradable implants is mainly attributed to the excellent biocompatibility of Zn and its important role in many physiological reactions. In addition, Zn based implants do not tend to produce hydrogen gas in in vivo conditions and hence do not promote the danger of gas embolism. However, Zn based implants can provoke encapsulation processes that, practically, may isolate the implant from its surrounding media, which limits its capability of performing as an acceptable biodegradable material. To overcome this problem, previous research carried out by the authors has paved the way for the development of Zn-Fe based alloys that have a relatively increased corrosion rate compared to pure Zn. The present study aims to evaluate the effect of 0.3–1.6% Ca on the in vitro behavior of Zn-Fe alloys and thus to further address the encapsulation problem. The in vitro assessment included immersion tests and electrochemical analysis in terms of open circuit potential, potentiodynamic polarization, and impedance spectroscopy in phosphate buffered saline (PBS) solution at 37 °C. The mechanical properties of the examined alloys were evaluated by tension and hardness tests while cytotoxicity properties were examined using indirect cell metabolic activity analysis. The obtained results indicated that Ca additions increased the corrosion rate of Zn-Fe alloys and in parallel increased their strength and hardness. This was mainly attributed to the formation of a Ca-rich phase in the form CaZn13. Cytotoxicity assessment showed that the cells’ metabolic activity on the tested alloys was adequate at over 90%, which was comparable to the cells’ metabolic activity on an inert reference alloy Ti-6Al-4V.

scholarly journals AHA1 upregulates IDH1 and metabolic activity to promote growth and metastasis and predicts prognosis in osteosarcoma

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Diwei Zheng ◽  
Weihai Liu ◽  
Wenlin Xie ◽  
Guanyu Huang ◽  
Qiwei Jiang ◽  
...  
Keyword(s):  
Metabolic Activity ◽  
Cancer Metabolism ◽  
Cancer Metastasis ◽  
Isocitrate Dehydrogenase 1 ◽  
Cell Growth And Migration ◽  
And Migration ◽  
The Relationship ◽  
Common Primary Malignant Bone

AbstractOsteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. Although activator of HSP90 ATPase activity 1 (AHA1) is reported to be a potential oncogene, its role in osteosarcoma progression remains largely unclear. Since metabolism reprogramming is involved in tumorigenesis and cancer metastasis, the relationship between AHA1 and cancer metabolism is unknown. In this study, we found that AHA1 is significantly overexpressed in osteosarcoma and related to the prognosis of osteosarcoma patients. AHA1 promotes the growth and metastasis of osteosarcoma both in vitro and in vivo. Mechanistically, AHA1 upregulates the metabolic activity to meet cellular bioenergetic needs in osteosarcoma. Notably, we identified that isocitrate dehydrogenase 1 (IDH1) is a novel client protein of Hsp90-AHA1. Furthermore, the IDH1 protein level was positively correlated with AHA1 in osteosarcoma. And IDH1 overexpression could partially reverse the effect of AHA1 knockdown on cell growth and migration of osteosarcoma. Moreover, high IDH1 level was also associated with poor prognosis of osteosarcoma patients. This study demonstrates that AHA1 positively regulates IDH1 and metabolic activity to promote osteosarcoma growth and metastasis, which provides novel prognostic biomarkers and promising therapeutic targets for osteosarcoma patients.

scholarly journals In vitro and in vivo assessment of biomedical Mg–Ca alloys for bone implant applications

2018 ◽  
Vol 16 (3) ◽  
pp. 126-136 ◽  
Author(s):  
Preeti Makkar ◽  
Swapan Kumar Sarkar ◽  
Andrew R. Padalhin ◽  
Byoung-Gi Moon ◽  
Young Seon Lee ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Bone Formation ◽  
Femoral Condyle ◽  
Immersion Test ◽  
Hydrogen Gas ◽  
In Vivo Studies ◽  
Biodegradable Implant ◽  
In Vitro Degradation

Background: Magnesium (Mg)-based alloys are considered to be promising materials for implant application due to their excellent biocompatibility, biodegradability, and mechanical properties close to bone. However, low corrosion resistance and fast degradation are limiting their application. Mg–Ca alloys have huge potential owing to a similar density to bone, good corrosion resistance, and as Mg is essential for Ca incorporation into bone. The objective of the present work is to determine the in vitro degradation and in vivo performance of binary Mg– xCa alloy ( x = 0.5 or 5.0 wt%) to assess its usability for degradable implant applications. Methods: Microstructural evolutions for Mg– xCa alloys were characterized by optical, SEM, EDX, and XRD. In vitro degradation tests were conducted via immersion test in phosphate buffer saline solution. In vivo performance in terms of interface, biocompatibility, and biodegradability of Mg– xCa alloys was examined by implanting samples into rabbit femoral condyle for 2 and 4 weeks. Results: Microstructural results showed the enhancement in intermetallic Mg2Ca phase with increase in Ca content. Immersion tests revealed that the dissolution rate varies linearly, with Ca content exhibiting more hydrogen gas evolution, increased pH, and higher degradation for Mg–5.0Ca alloy. In vivo studies showed good biocompatibility with enhanced bone formation for Mg–0.5Ca after 4 weeks of implantation compared with Mg–5.0Ca alloy. Higher initial corrosion rate with prolonged inflammation and rapid degradation was noticed in Mg–5.0Ca compared with Mg–0.5Ca alloy. Conclusions: The results suggest that Mg–0.5Ca alloy could be used as a temporary biodegradable implant material for clinical applications owing to its controlled in vivo degradation, reduced inflammation, and high bone-formation capability.

Repurposing celecoxib analogues as leads for antibiotics

2021 ◽  
Author(s):  
Baowei Yang ◽  
Yicheng Mei ◽  
Qianhui Li ◽  
Mengyuan Zhang ◽  
Huiling Tang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Enzyme Inhibition ◽  
Mild Improvement ◽  
New Antibiotics ◽  
Cytotoxicity Assessment ◽  
Improvement In Survival ◽  
In Vivo Cytotoxicity ◽  
Further Development

There is an urgent need for new antibiotics and alternative strategies to combat bacterial pathogens. Molecular docking, antibacterial evaluation in vitro and in vivo, cytotoxicity assessment and enzyme inhibition analyses were performed. Compound 12 exhibited antimicrobial activity against Staphylococcus aureus (MIC: 4 μg/ml), various clinically isolated strains of MRSA (MIC: 4–16 μg/ml) and Acinetobacter baumannii (MIC: 4 μg/ml) when combined with subinhibitory concentrations of colistin B. Compound 12 (20 mg/kg) yielded mild improvement in survival of methicillin-resistant Staphylococcus aureus (MRSA)-infected mice. Additionally, enzyme inhibition tests showed that compound 12 exhibited inhibitory effects against S. aureus dihydrofolate reductase (105.1 μg/ml) and DNA gyrase (122.8 μg/ml). Compound 12 is a promising antibacterial candidate for further development.

Coverslip hypoxia: a novel method for studying cardiac myocyte hypoxia and ischemia in vitro

2004 ◽  
Vol 287 (4) ◽  
pp. H1801-H1812 ◽  
Author(s):  
Kelly R. Pitts ◽  
Christopher F. Toombs
Keyword(s):  
Metabolic Activity ◽  
Cardiac Myocyte ◽  
Experimental Models ◽  
Membrane Dynamics ◽  
Neonatal Rat ◽  
Simple Method ◽  
Glass Coverslip ◽  
Media Volume

In vitro experimental models designed to study the effects of hypoxia and ischemia typically employ oxygen-depleted media and/or hypoxic chambers. These approaches, however, allow for metabolites to diffuse away into a large volume and may not replicate the high local concentrations that occur in ischemic myocardium in vivo. We describe herein a novel and simple method for creating regional hypoxic and ischemic conditions in neonatal rat cardiac myocyte monolayers. This method consists of creating a localized diffusion barrier by placing a glass coverslip over a portion of the monolayer. The coverslip restricts covered myocytes to a thin film of media while leaving uncovered myocytes free to access the surrounding bulk media volume. Myocytes under the coverslip undergo marked morphology changes over time as assessed by video microscopy. Fluorescence microscopy shows that these changes are accompanied by alterations in mitochondrial membrane potential and plasma membrane dynamics and eventually result in myocyte death. We also show that the metabolic activity of myocytes drives cell necrosis under the coverslip. In addition, the intracellular pH of synchronously contracting myocytes under the coverslip drops rapidly, which further implicates metabolic activity in regulating cell death under the coverslip. In contrast with existing models of hypoxia/ischemia, this technique provides a simple and effective way to create hypoxic/ischemic conditions in vitro. Moreover, we conclude that myocyte death is hastened by the combination of hypoxia, metabolites, and acidosis and is facilitated by a reduction in media volume, which may better represent ischemic conditions in vivo.

scholarly journals Brazilian Red Propolis Is as Effective as Amoxicillin in Controlling Red-Complex of Multispecies Subgingival Mature Biofilm In Vitro

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 432
Author(s):  
Kadmo Azevedo de Figueiredo ◽  
Helio Doyle Pereira da Silva ◽  
Stela Lima Farias Miranda ◽  
Francisco Jerfeson dos Santos Gonçalves ◽  
Arlene Pereira de Sousa ◽  
...  
Keyword(s):  
Metabolic Activity ◽  
Positive Control ◽  
Negative Control ◽  
In Vivo Studies ◽  
Complex Species ◽  
Hybridization Data ◽  
Cell Counts ◽  
Actinomyces Species

This study investigated the effects of Brazilian Red Propolis (BRP) extract on seven-day-old multispecies subgingival biofilms. Mixed biofilm cultures containing 31 species associated with periodontal health or disease were grown for six days on a Calgary device. Then, mature biofilms were treated for 24 h with BRP extract at different concentrations (200–1600 µg/mL), amoxicillin (AMOXI) at 54 µg/mL (positive control) or vehicle (negative control). Biofilm metabolic activity was determined by colorimetry, and bacterial counts/proportions were determined by DNA–DNA hybridization. Data were analyzed by Kruskal–Wallis and Dunn’s tests. Treatment with BRP at 1600, 800 and 400 μg/mL reduced biofilm metabolic activity by 56%, 56% and 57%, respectively, as compared to 65% reduction obtained with AMOXI. Mean total cell counts were significantly reduced in all test groups (~50–55%). Lower proportions of red, green and yellow complex species were observed upon treatment with BRP (400 µg/mL) and AMOXI, but only AMOXI reduced the proportions of Actinomyces species. In conclusion, BRP extract was as effective as AMOXI in killing seven-day-old multispecies biofilm pathogens and did not affect the levels of the host-compatible Actinomyces species. These data suggest that BRP may be an alternative to AMOXI as an adjunct in periodontal therapy. In vivo studies are needed to validate these results.

Design and preparation of open circuit potential biosensor for in vitro and in vivo glucose monitoring

2016 ◽  
Vol 409 (1) ◽  
pp. 161-168 ◽  
Author(s):  
Yonggui Song ◽  
Dan Su ◽  
Yuan Shen ◽  
Hongyu Liu ◽  
Li Wang
Keyword(s):  
Open Circuit Potential ◽  
Glucose Monitoring ◽  
Open Circuit

scholarly journals AVA4746, an Orally Available, Clinical Grade Antagonist of Integrin Alpha 4, Sensitizes Pre-B Cell Acute Lymphoblastic Leukemia to Chemotherapy

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2765-2765 ◽  
Author(s):  
Yongsheng Ruan ◽  
Eun Ji Gang ◽  
Hye-Na Kim ◽  
Chintan Parekh ◽  
Hisham Abdel-Azim ◽  
...  
Keyword(s):  
Overall Survival ◽  
Drug Resistance ◽  
Acute Lymphoblastic Leukemia ◽  
Metabolic Activity ◽  
Research Funding ◽  
Lymphoblastic Leukemia ◽  
Drug Resistant ◽  
Support Research

Abstract Background. Even though remarkable progress has been made in the treatment of childhood acute lymphoblastic leukemia (ALL), salvage of relapse patients remains a challenge. The role of the bone marrow (BM) microenvironment is critical to protect leukemia cells from chemotherapy. The BM microenvironment promotes cell adhesion-mediated drug resistance (CAM-DR) in ALL.We and others have shown that the adhesion molecule integrin α4, referred to hereafter as α4, mediates drug resistance of B-ALL. In our previous studies, we showed that both α4 blockade by natalizumab and inhibition by the small molecule α4 antagonist TBC3486 can sensitize relapsed ALL cells to chemotherapy. However, no α4 targeting therapy is currently clinically available to treat leukemia. Here, we preclinically evaluate a novel non-peptidic small molecule antagonist, AVA4746, which has been safely used in clinical studies, as a potential new approach to combat drug resistant ALL. Method. Six refractory or relapsed primary pre-B ALL cases were used for in vitro studies. Viability was assessed by trypan blue counts or annexin V/7AAD flow cytometric analysis and metabolic activity was evaluated by Cytoscan WST-1 assay. For in vivo evaluation a NOD/SCID IL2Rγ-/- xenograft model of primary pre-B ALL (LAX7R) was used.AVA4746 (15mg/kg) was administered by oral gavage twice a day continuously for 14 days, and vincristine, dexamethasone, L-asparaginase (VDL) was given intraperitoneally (weekly) for 4 weeks. Overall survival was determined by Kaplan-Meier Survival analysis. Results. AVA4746 caused a significant decrease in mean fluorescence intensity (MFI) of α4 expression in six out of six ALL cases at doses of both 5μM and 25μM after 24 hours and 96 hours compared to DMSO control. Interestingly, decreased protein expression of α4 was also observed by Western Blot analysis all six ALL cases. We tested next in two cases (LAX53, ICN13), if AVA4746 de-adheres ALL cells from its counter receptor VCAM-1. The percentages of adherence after treatment with AVA4746 (25μM) were significantly lower than after DMSO treatment (10.3%±4.9% vs. 99.9%±7.6%, p= 0.00007 for LAX7R; 8.1%±1.0% vs. 100.1%±13.6%, p= 0.0003 for LAX53; 9.0%±1.6% vs. 100.0%±14.0%, p=0.0004 for ICN13). AVA4746 was not associated with apoptosis in vitro alone or in combination with chemotherapy (VDL). Metabolic activity as assessed by WST-1 assay was markedly decreased by AVA4746 in two of two ALL cases. AVA4746 also decreased ALL proliferation in two out of two ALL samples tested. In vivo, AVA4746 in combination with VDL chemotherapy treatment led to significant prolongation of overall survival (n=6) compared with the VDL only treated group (n=6) (MST= 78.5 days vs MST= 68 days; P<0.05). There was no significant difference in survival between the PBS control group (n=5) and the AVA4746 mono-treatment group (n=5) (MST=38days vs MST= 38days). Conclusion. We have identified α4 as a central adhesion molecule in CAM-DR of ALL and have shown that AVA-4746, an orally available and specific α4 antagonist, which has been safely used in clinical studies, downregulates α4 in primary ALL and functionally de-adheres them from VCAM-1. Critically, we demonstrated that inhibition of α4 in combination with standard chemotherapy can prolong the survival of NSG mice bearing pre-B ALL. These data support further study of inhibition of α4 using AVA4746 as a novel strategy to treat drug resistant B lineage ALL. Disclosures Bhojwani: Amgen: Other: Blinatumumab global pediatric advisory board 2015. Wayne:Spectrum Pharmaceuticals: Honoraria, Other: Travel Support, Research Funding; Kite Pharma: Honoraria, Other: Travel support, Research Funding; Pfizer: Consultancy, Honoraria, Other: Travel Support; Medimmune: Honoraria, Other: Travel Support, Research Funding; NIH: Patents & Royalties. Kim:Antisense Therapeutics Ltd: Patents & Royalties.

scholarly journals In Vivo Simulation of Magnesium Degradability Using a New Fluid Dynamic Bench Testing Approach

2019 ◽  
Vol 20 (19) ◽  
pp. 4859 ◽  
Author(s):  
Ole Jung ◽  
Dario Porchetta ◽  
Marie-Luise Schroeder ◽  
Martin Klein ◽  
Nils Wegner ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Test Bench ◽  
Fluid Dynamic ◽  
Dynamic Test ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Human Blood Plasma ◽  
Degradation Rates

The degradation rate of magnesium (Mg) alloys is a key parameter to develop Mg-based biomaterials and ensure in vivo-mechanical stability as well as to minimize hydrogen gas production, which otherwise can lead to adverse effects in clinical applications. However, in vitro and in vivo results of the same material often differ largely. In the present study, a dynamic test bench with several single bioreactor cells was constructed to measure the volume of hydrogen gas which evolves during magnesium degradation to indicate the degradation rate in vivo. Degradation medium comparable with human blood plasma was used to simulate body fluids. The media was pumped through the different bioreactor cells under a constant flow rate and 37 °C to simulate physiological conditions. A total of three different Mg groups were successively tested: Mg WE43, and two different WE43 plasma electrolytically oxidized (PEO) variants. The results were compared with other methods to detect magnesium degradation (pH, potentiodynamic polarization (PDP), cytocompatibility, SEM (scanning electron microscopy)). The non-ceramized specimens showed the highest degradation rates and vast standard deviations. In contrast, the two PEO samples demonstrated reduced degradation rates with diminished standard deviation. The pH values showed above-average constant levels between 7.4–7.7, likely due to the constant exchange of the fluids. SEM revealed severe cracks on the surface of WE43 after degradation, whereas the ceramized surfaces showed significantly decreased signs of corrosion. PDP results confirmed the improved corrosion resistance of both PEO samples. While WE43 showed slight toxicity in vitro, satisfactory cytocompatibility was achieved for the PEO test samples. In summary, the dynamic test bench constructed in this study enables reliable and simple measurement of Mg degradation to simulate the in vivo environment. Furthermore, PEO treatment of magnesium is a promising method to adjust magnesium degradation.

Synthesis and studies of thiazolidinedione–isatin hybrids as α-glucosidase inhibitors for management of diabetes

2021 ◽  
Vol 13 (5) ◽  
pp. 457-485
Author(s):  
Ramandeep Kaur ◽  
Rajnish Kumar ◽  
Nilambra Dogra ◽  
Ashok Kumar ◽  
Ashok Kumar Yadav ◽  
...  
Keyword(s):  
In Silico ◽  
Binding Free Energy ◽  
Biological Evaluation ◽  
Free Energy Calculations ◽  
Standard Drug ◽  
Glucosidase Inhibitors ◽  
Cytotoxicity Studies ◽  
Cytotoxicity Assessment

Aim: Keeping in view the side effects associated with clinically used α-glucosidase inhibitors, novel thiazolidinedione–isatin hybrids were synthesized and evaluated by in vitro, in vivo and in silico procedures. Materials & methods: Biological evaluation, cytotoxicity assessment, molecular docking, binding free energy calculations and molecular dynamics studies were performed for hybrids. Results: The most potent inhibitor A-10 (IC50 = 24.73 ± 0.93 μM) was competitive in manner and observed as non-cytotoxic. A-10 possessed higher efficacy than the standard drug (acarbose) during in vivo biological testing. Conclusion: The enzyme inhibitory potential and safety profile of synthetic molecules was recognized after in vitro, in vivo, in silico and cytotoxicity studies. Further structural optimization of A-10 can offer potential hit molecules suitable for future investigations.

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