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Οκτ 19
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- Pathophysiology of Blood-Brain Barrier in Brain In...
- Mast Cell – Glia Dialogue in Chronic Pain and Neur...
- Potential Use of Nanomedicine for Drug Delivery Ac...
- Nanowired Drug Delivery Across the Blood-Brain Bar...
- Involvement of the Blood-Brain Barrier in Metaboli...
- Breakdown of Blood-Brain and Blood-Spinal Cord Bar...
- Spinal Cord Injury Changes Cytokine Transport
- Merging Transport Data for Choroid Plexus with Blo...
- Neuroprotection by Methylene Blue in Cerebral Glob...
- Blood-Brain Barrier Changes in High Altitude
- Current and Next Generation Topical Anti-Skin Canc...
- Meta-analysis Reveals No Association of DNMT3B -14...
- Targeting autophagy sensitizes BRAF-mutant thyroid...
- Effects of Testosterone Supplementation for 3-Year...
- Thyroid autoimmunity impairs the thyroidal respons...
- Body composition changes after very low-calorie-ke...
- Low-dose aspirin and sporadic anovulation in the E...
- The effect of TSH-suppression on vertebral trabecu...
- Familial Multiplicity of Estrogen Insensitivity As...
- Diagnosis of ABCC8 congenital hyperinsulinism of i...
- Oral nitrite circumvents antiseptic mouthwash-indu...
- Degradation of the cytostatic 5-Fluorouracil in wa...
- Calcium polysulphide, its applications and emergin...
- A modeling approach to direct interspecies electro...
- Technoeconomic perspectives on sustainable CO 2 ca...
- Humor Appreciation Involves Parametric and Synchro...
- An Accurate Method of Designing and Performing Ind...
- MACF1 Controls Migration and Positioning of Cortic...
- Human-derived extracellular matrix from Wharton’s ...
- Mucoadhesive chitosan hydrogels as rectal drug del...
- Functional improvement of hemostatic dressing by a...
- Carbon nanotube-composite hydrogels promote interc...
- Enzyme-mediated stiffening hydrogels for probing a...
- Polymeric nanoparticles enable reversing macrophag...
- Synergistic thermoradiotherapy based on PEGylated ...
- Micellar nanocomplexes for biomagnetic delivery of...
- Hearing Aid Batteries: The Past, Present, and Future
- Monitoring Progression of 12 Cases of Non-Operated...
- Evaluation of Rigid Cochlear Models for Measuring ...
- Bilateral Facial Paralysis as Presenting Symptoms ...
- An Unusual Case of Lymphoepithelioma-Like Carcinom...
- Diagnostic Criteria for Detection of Vestibular Sc...
- Posterior Fossa Spontaneous Cerebrospinal Fluid Le...
- Cochlear Implantation in the Elderly: Does Age Mat...
- COMPARISON OF FGF-2, FLOX, AND GELFOAM PATCHING FO...
- TRAUMATIC TYMPANIC MEMBRANE PERFORATION REPAIR USI...
- The Stapes Bar: An Unusual Cause of Conductive Hea...
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Οκτ 19
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! # Ola via Alexandros G.Sfakianakis on Inoreader
Η λίστα ιστολογίων μου
Τετάρτη 19 Οκτωβρίου 2016
Pathophysiology of Blood-Brain Barrier in Brain Injury in Cold and Hot Environments: Novel Drug Targets for Neuroprotection
http://ift.tt/2e6X59Y
Mast Cell – Glia Dialogue in Chronic Pain and Neuropathic Pain: Blood-Brain Barrier Implications
http://ift.tt/2ejNQi1
Potential Use of Nanomedicine for Drug Delivery Across the Blood-Brain Barrier in Healthy and Diseased Brain
http://ift.tt/2e71hX2
Nanowired Drug Delivery Across the Blood-Brain Barrier in Central Nervous System Injury and Repair
http://ift.tt/2ejRbgH
Breakdown of Blood-Brain and Blood-Spinal Cord Barriers During Acute Methamphetamine Intoxication: Role of Brain Temperature
http://ift.tt/2ejQl3E
Merging Transport Data for Choroid Plexus with Blood-Brain Barrier to Model CNS Homeostasis and Disease More Effectively
http://ift.tt/2ejRsAs
Neuroprotection by Methylene Blue in Cerebral Global Ischemic Injury Induced Blood-Brain Barrier Disruption and Brain Pathology: A Review
http://ift.tt/2e6Z9yQ
Current and Next Generation Topical Anti-Skin Cancer Therapeutics
Non-melanoma skin cancers are among the most commonly diagnosed skin cancers in the world. Ultraviolet radiation is a primary carcinogen resulting in UV induced mutations, loss of activity in tumour suppressor genes and the over expression of oncogenes in keratinocytes resulting in the development of skin malignancies. With the continued rising rate of non-melanoma skin cancer, topical therapies have become an established treatment method for effective lesion clearance. Current topical therapies include 5-fluorouracil, imiquimod, diclofenac, ingenol mebutate and photodynamic therapy. With high lesion recurrence rates still presenting as an issue following topical treatment, lack of drug selectivity for cancer cells, severe side effects from topical agent use and patient non-compliance due to prolonged treatment periods, new novel topical therapies need to be explored and developed. New therapies must target and clear both subclinical and clinically presenting skin cancers by interrupting the molecular mechanisms that induce and sustain the proliferation of neoplastic cells. Piperlongumine and EBC-46 are two naturally occurring small molecules which have demonstrated effective induction of cancer cell death. Piperlongumine, an amide isolated from the pepper, Piper longum, has demonstrated cancer cell death selectivity yet has no impact on healthy rapidly dividing primary cells. EBC-46 is a diterpene ester isolated from the seed of the fruit, Fontainea picrosperma. EBC-46 induces rapid inflammation and necrosis resulting in tumour ablation following intra-lesional injection. The development of Piperlongumine and EBC-46, as new topical agents offers a unique opportunity to further explore and exploit these selective properties for a more efficient and targeted approach to topical non -melanoma skin cancer treatment.
http://ift.tt/2dmEzcc
Meta-analysis Reveals No Association of DNMT3B -149 C>T Gene Polymorphism With Overall Cancer Risk
Background: DNA methyltransferase-3B (DNMT3B) plays a key role in establishment and maintenance of genomic methylation patterns. Polymorphism in promoter region -149 C>T (C46359T) of DNMT3B gene may alter DNMT3B activity which leads to increased susceptibility to cancer. Inconsistent results regarding this have been reported in a number of studies. </p><p> Objective: To carry out a meta-analysis of the studies reported to assess the precise relationship between the DNMT3B -149 C>T polymorphism and the overall cancer risk. </p><p> Method: PubMed (MEDLINE) web database was searched for the studies concerning DNMT3B -149 C>T polymorphism and its association with cancer risk. The pooled odds ratios (ORs) along with 95% confidence intervals (95% CIs) were calculated for all the genetic models, from the selected case-control studies, by meta-analysis. </p><p> Results: Overall eighteen studies containing 5583 cancer cases and 7618 controls were analyzed. No significant risk was observed overall for T allele carrier (T vs. C: p=0.303; OR=1.032, 95% CI=0.972- 1.097), homozygous (TT vs. CC: p=0.336; OR=1.063, 95% CI=0.939–1.204), heterozygous (CT vs. CC: p=0.802; OR=1.022, 95% CI=0.860-1.216), dominant (TT vs. CC+CT: p=0.298; OR=1.101, 95% CI=0.919-1.319) and recessive (TT+CT vs. CC: p=0.656; OR=1.021, 95% CI=0.931-1.121) genetic models. Subgroup analysis of Asian and Caucasian populations also did not demonstrate any cancer risk in all the genetic models studied. </p><p> Conclusion: Our meta-analysis proposes that the DNMT3B -149 C>T polymorphism may not be an independent predisposing factor for the risk of cancer. However, larger sample size and expression studies are required to confirm the observation. </p><p>
http://ift.tt/2e0ugIw
Targeting autophagy sensitizes BRAF-mutant thyroid cancer to vemurafenib
The Journal of Clinical Endocrinology &Metabolism, Early Release.
http://ift.tt/2ek8EdL
Effects of Testosterone Supplementation for 3-Years on Muscle Performance and Physical Function in Older Men
The Journal of Clinical Endocrinology &Metabolism, Early Release.
http://ift.tt/2dq3lmJ
Thyroid autoimmunity impairs the thyroidal response to hCG: two population-based prospective cohort studies
The Journal of Clinical Endocrinology &Metabolism, Early Release.
http://ift.tt/2ek7q1T
Body composition changes after very low-calorie-ketogenic diet in obesity evaluated by three standardized methods
The Journal of Clinical Endocrinology &Metabolism, Early Release.
http://ift.tt/2dq49Ii
Low-dose aspirin and sporadic anovulation in the EAGeR randomized trial
The Journal of Clinical Endocrinology &Metabolism, Early Release.
http://ift.tt/2ek9rLm
The effect of TSH-suppression on vertebral trabecular bone scores in patients with differentiated thyroid carcinoma
The Journal of Clinical Endocrinology &Metabolism, Early Release.
http://ift.tt/2dq4MBL
Familial Multiplicity of Estrogen Insensitivity Associated with a Loss-of-Function ESR1 Mutation
The Journal of Clinical Endocrinology &Metabolism, Early Release.
http://ift.tt/2ek7nDf
Diagnosis of ABCC8 congenital hyperinsulinism of infancy in a 20 year-old man evaluated for factitious hypoglycemia.
The Journal of Clinical Endocrinology &Metabolism, Early Release.
http://ift.tt/2dq15Mc
Oral nitrite circumvents antiseptic mouthwash-induced disruption of enterosalivary circuit of nitrate and promotes nitrosation and blood pressure lowering effect
Publication date: Available online 18 October 2016
Source:Free Radical Biology and Medicine
Author(s): Lucas C. Pinheiro, Graziele C. Ferreira, Jefferson H. Amaral, Rafael L. Portella, Sandra de O.C. Tella, Madla A. Passos, Jose E. Tanus-Santos
The nitric oxide (NO•) metabolites nitrite and nitrate exert antihypertensive effects by mechanisms that involve gastric formation of S-nitrosothiols. However, while the use of antiseptic mouthwash (AM) is known to attenuate the responses to nitrate by disrupting its enterosalivary cycle, there is little information about whether AM attenuates the effects of orally administered nitrite. We hypothesized that the antihypertensive effects of orally administered nitrite would not be prevented by AM because, in contrast to oral nitrate, oral nitrite could promote S-nitrosothiols formation in the stomach without intereference by AM. Chronic effects of oral nitrite or nitrate were studied in two-kidney, one-clip (2K1C) hypertensive rats (and normotensive controls) treated with AM (or vehicle) once/day. We found that orally administered nitrite exerts antihypertensive effects that were not affected by AM. This finding contrasts with lack of antihypertensive responses to oral nitrate in 2K1C hypertensive rats treated with AM. Nitrite and nitrate treatments increased plasma nitrites, nitrates, and S-nitrosothiols concentrations. However, while treatment with AM attenuated the increases in plasma nitrite concentrations after both nitrite and nitrate treatments, AM attenuated the increases in S-nitrosothiols in nitrate-treated rats, but not in nitrite-treated rats. Moreover, AM attenuated vascular S-nitrosylation (detected by the SNO-RAC method) after nitrate, but not after nitrite treatment. Significant correlations were found between the hypotensive responses and S-nitrosothiols, and vascular S-nitrosylation levels. These results show for the first time that oral nitrite exerts antihypertensive effects notwithstanding the fact that antiseptic mouthwash disrupts the enterosalivary circulation of nitrate. Our results support a major role for S-nitrosothiols formation resulting in vascular S-nitrosylation as a key mechanism for the antihypertensive effects of both oral nitrite and nitrate.
Graphical abstract
http://ift.tt/2e6OYdC
Degradation of the cytostatic 5-Fluorouracil in water by Fenton and photo-assisted oxidation processes
Abstract
Cytostatics are part of the forefront research topics due to their high prescription, high toxicity, and the lack of effective solutions to stop their entrance and spread in the environment. Among them, 5-Fluorouracil (5-Fu) has received particular attention because is one of the most prescribed active substances in chemotherapy worldwide. The degradation of 5-Fu by advanced oxidation processes (AOPs) is a poorly addressed topic, and this work brings valuable inputs concerning this matter. Herein, the efficacy of Fenton's process in the degradation of 5-Fu is explored for the first time; the study of the main variables and its successful application to the treatment of real wastewaters is demonstrated. Moreover, hydrogen peroxide-based and photo-assisted techniques (direct photolysis, photodegradation with H2O2 and photo-Fenton) are also investigated for purposes of comparison. Under the best operation conditions obtained (T = 30 °C, [Fe2+]0 = 0.5 mM; [H2O2]0 = 240 mM and pH = 3 for [5-Fu]0 = 0.38 mM), 5-Fu was completely eliminated after 2 h of Fenton's reaction and about 50 % of mineralization was reached after 8 h. The best performance was obtained by the photo-Fenton process, with 5-Fu mineralization level as high as 67 %, using an iron dose within the legal limits required for direct water discharge. Toxicity (towards Vibrio fischeri) of the effluents that resulted from the application of the above-mentioned AOPs was also evaluated; it was found that the degradation products generated from the photo-assisted processes are less toxic than the parent compound, putting into evidence the relevance of such technologies for degradation of cytostatics like 5-Fu.
http://ift.tt/2esVCGQ
Calcium polysulphide, its applications and emerging risk of environmental pollution—a review article
Abstract
Easy availability, preparation technique, and economic value make calcium polysulphide (CaSx ) a very useful inorganic chemical for various field and industrial applications. In this article, disparate applications of CaSx solution have been reviewed to suggest potential and future consolidation. This article also encompasses the physiochemical properties and production of CaSx solution, with critical appraisal on research focusing on CaSx application in agriculture industries and removal of potentially toxic elements (PTEs) from the environment. The kinetics of CaSx , technical issues associated with optimization of its dosage and environmental fate is also discussed in detail. This study covers almost all of the peer-reviewed research that has been performed since 1914. Some of the critiques in this article include the lack of integration between the exposure effect and the efficiency of treatment method, effects of oxidizing environments on the long-term performance of CaSx solution, and kinetics of CaSx solution with the PTEs. The working model of CaSx with PTEs is still system dependent, and therefore cannot be used with other applications. The kinetics of CaSx is described in detail with various phase stoichiometric reactions. Environmental fate is discussed based on applications, government reports, peer-reviewed articles and kinetics of CaSx , which provides a clear picture of emerging contaminants in the environment in relation to the insect resistance and ecotoxicology. Real time, lab based research articles are needed to identify toxicity limits of CaSx in environment in order to describe its effective permissible limit in environmental system. This review article provides a risk assessment of environmental pollution by CaSx based on its physicochemical characteristic, stoichiometry, kinetics, field, and industrial applications.
http://ift.tt/2e51oA7
A modeling approach to direct interspecies electron transfer process in anaerobic transformation of ethanol to methane
Abstract
Recent studies have shown that direct interspecies electron transfer (DIET) plays an important part in contributing to methane production from anaerobic digestion. However, so far anaerobic digestion models that have been proposed only consider two pathways for methane production, namely, acetoclastic methanogenesis and hydrogenotrophic methanogenesis, via indirect interspecies hydrogen transfer, which lacks an effective way for incorporating DIET into this paradigm. In this work, a new mathematical model is specifically developed to describe DIET process in anaerobic digestion through introducing extracellular electron transfer as a new pathway for methane production, taking anaerobic transformation of ethanol to methane as an example. The developed model was able to successfully predict experimental data on methane dynamics under different experimental conditions, supporting the validity of the developed model. Modeling predictions clearly demonstrated that DIET plays an important role in contributing to overall methane production (up to 33 %) and conductive material (i.e., carbon cloth) addition would significantly promote DIET through increasing ethanol conversion rate and methane production rate. The model developed in this work will potentially enhance our current understanding on syntrophic metabolism via DIET.
http://ift.tt/2esWVVU
Humor Appreciation Involves Parametric and Synchronized Activity in the Medial Prefrontal Cortex and Hippocampus
Humor perception is a ubiquitous phenomenon in human societies. In theories of humor perception, three factors, non-seriousness, social context, and incongruity, have been implicated in humor. In another theory, however, elaboration and reinterpretation of contexts are considered to play a role in eliciting humor. Although the neural correlates of humor appreciation have been investigated using neuroimaging methods, only a few studies have conducted such experiments under natural conditions. In the present study, two functional magnetic resonance imaging experiments, using a comedy movie as a stimulus, were conducted to investigate the neural correlates of humor under natural conditions. The subjects' brain activity was measured while watching and enjoying a movie. In experiment 1, a parametric analysis showed that the medial prefrontal cortex (MPFC) and hippocampus/amygdala had a positive relationship with the subjective rating of funniness. In experiment 2, intersubject correlation was analyzed to investigate synchronized activity across all participants. Signal synchronization that paralleled increased funniness ratings was observed in the MPFC and hippocampus. Thus, it appears that both parametric and synchronized activity in the MPFC and hippocampus are important during humor appreciation. The present study has revealed the brain regions that are predominantly involved in humor sensation under natural condition.
http://ift.tt/2esUHG4
An Accurate Method of Designing and Performing Individual-Specific Genioglossus Advancement
There is too much individual patient variation in mandibular anatomy for any single described genioglossus advancement technique to be used consistently. Virtual surgical planning allows surgeons to design genioglossus osteotomy that captures the structures of interest. Intraoperative osteotomy and positioning guides mitigate known risks of the procedure while maximizing the reproducibility and efficacy of the procedure. In this report, we demonstrate the protocol step by step as it had been used on 10 patients, and we highlight 3 clinical scenarios that exemplify its utility.
http://ift.tt/2ePT3Bz
MACF1 Controls Migration and Positioning of Cortical GABAergic Interneurons in Mice
GABAergic interneurons develop in the ganglionic eminence in the ventral telencephalon and tangentially migrate into the cortical plate during development. However, key molecules controlling interneuron migration remain poorly identified. Here, we show that microtubule-actin cross-linking factor 1 (MACF1) regulates GABAergic interneuron migration and positioning in the developing mouse brain. To investigate the role of MACF1 in developing interneurons, we conditionally deleted the MACF1 gene in mouse interneuron progenitors and their progeny using Dlx5/6-Cre-IRES-EGFP and Nkx2.1-Cre drivers. We found that MACF1 deletion results in a marked reduction and defective positioning of interneurons in the mouse cerebral cortex and hippocampus, suggesting abnormal interneuron migration. Indeed, the speed and mode of interneuron migration were abnormal in the MACF1-mutant brain, compared with controls. Additionally, MACF1-deleted interneurons showed a significant reduction in the length of their leading processes and dendrites in the mouse brain. Finally, loss of MACF1 decreased microtubule stability in cortical interneurons. Our findings suggest that MACF1 plays a critical role in cortical interneuron migration and positioning in the developing mouse brain.
http://ift.tt/2e4ZGyK
Human-derived extracellular matrix from Wharton’s jelly: an untapped substrate to build up a standardized and homogeneous coating for vascular engineering
Publication date: Available online 18 October 2016
Source:Acta Biomaterialia
Author(s): Pan Dan, Émilie Velot, Grégory Francius, Patrick Menu, Véronique Decot
One of the outstanding goals in tissue engineering is to develop a natural coating surface which is easy to manipulate, effective for cell adhesion and fully biocompatible. The ideal surface would be derived from human tissue, perfectly controllable, and pathogen-free, thereby satisfying all of the standards of the health authorities. This paper reports an innovative approach to coating surfaces using a natural extracellular matrix (ECM) extracted from the Wharton's jelly (WJ) of the umbilical cord (referred to as WJ-ECM). We have shown by atomic force microscopy (AFM), that the deposition of WJ-ECM on surfaces is homogenous with a controllable thickness, and that this easily-prepared coating is appropriate for both the adhesion and proliferation of human mesenchymal stem cells and mature endothelial cells. Furthermore, under physiological shear stress conditions, a larger number of cells remained adhered to WJ-ECM than to a conventional coating such as collagen − a result supported by the higher expression of both integrins α2 and β1 in cells cultured on WJ-ECM. Our data clearly show that Wharton's jelly is a highly promising coating for the design of human biocompatible surfaces in tissue engineering as well as in regenerative medicine.Statement of SignificanceDiscovery and design of biomaterial surface are a hot spot in the tissue engineering field. Natural matrix is preferred to mimic native cell microenvironment but its use is limited due to poor resource availability. Moreover, current studies often use single or several components of natural polymers, which is not the case in human body. This paper reports a natural extracellular matrix with full components derived from healthy human tissue: Wharton's jelly of umbilical cord. Reconstituting this matrix as a culture surface, our easily-prepared coating provides superior biocompatibility for stem and mature cells. Furthermore, we observed improved cell performance on this coating under both static and dynamic condition. This novel human derived ECM would be a promising choice for regenerative medicine.
Graphical abstract
http://ift.tt/2ejZRZd
Mucoadhesive chitosan hydrogels as rectal drug delivery vessels to treat ulcerative colitis
Publication date: Available online 18 October 2016
Source:Acta Biomaterialia
Author(s): Jinke Xu, Mifong Tam, Sepideh Samadei, Sophie Lerouge, Jake Barralet, Mary M. Stevenson, Marta Cerruti
Mucoadhesive drug delivery systems stick to mucosal tissues and prolong the local retention time of drugs. Since the colon is covered by a mucosal layer, mucoadhesive rectal formulations may improve treatment of such diseases as hypertension or colon cancer. Ulcerative colitis (UC) is an inflammatory bowel disease characterized by chronic inflammation of the colonic mucosa. It is commonly treated with sulfasalazine (SSZ), which is metabolized by the intestinal flora into the therapeutic 5-aminosalicylic acid (5-ASA) and a toxic by-product sulfapyridine (SP). SSZ can be administered orally or rectally. The latter route avoids unintended absorption of the drug or its degradation products in the upper gastrointestinal tract, but often fails due to limited retention time. Here, we propose a mucoadhesive hydrogel to improve the efficacy of rectal SSZ administration. The gel is made of catechol modified-chitosan (Cat-CS) crosslinked by genipin. After loading the gel with SSZ, we evaluated its efficacy in a mouse model of UC. Compared to oral SSZ treatment, rectal SSZ/Cat-CS delivery was more therapeutic, showed equivalent histological scores, and induced a lower plasma concentration of the potentially toxic SP by-product. These results show SSZ/Cat-CS rectal hydrogels are more effective and safer formulations for UC treatment than oral SSZ.
Graphical abstract
http://ift.tt/2ek1Mgf
Functional improvement of hemostatic dressing by addition of recombinant batroxobin
Publication date: Available online 18 October 2016
Source:Acta Biomaterialia
Author(s): Gyeung Mi Seon, Mi Hee Lee, Byeong-Ju Kwon, Min Sung Kim, Min-Ah Koo, Dohyun Kim, Young Seomun, Jong-Tak Kim, Jong-Chul Park
Although a number of natural materials have been used as hemostatic agents, many substances do not act quickly enough. Here, we created a novel dressings using collagen and chitosan with recombinant batroxobin (r-Bat) to promote faster and more effective hemostasis. We hypothesized that r-Bat would promote synergetic blood coagulation because it contains a blood coagulation active site different than those of collagen and chitosan. Our results suggest that each substances can maintain hemostatic properties while in the mixed dressings and that our novel hemostatic dressings promotes potent control of bleeding, as demonstrated by a whole blood assay and rat hemorrhage model. In a rat femoral artery model, the scaffold with a high r-Bat concentration more rapidly controlled excessive bleeding. This novel dressings has enormous possible for rapidly controlling bleeding and it improves upon the effect of collagen and chitosan used alone. Our novel r-Bat dressings is a possible candidate for improving preoperative care and displays promising properties as an absorbable agent in hemostasis.Statement of significanceDespite the excellent hemostatic properties of collagen and chitosan pads, they reported to brittle behavior and lack sufficient hemostatic effect within relevant time. Therefore, we created a novel pad using collagen and chitosan with recombinant batroxobin (r-Bat). r-Bat acts as a thrombin-like enzyme in the coagulation cascade. Specifically, r-Bat, in contrast to thrombin, only splits fibrinopeptide A off and does not influence other hemostatic factors or cells, which makes it clinically useful as a stable hemostatic agent. Also the materials in the pad have synergetic effect because they have different hemostatic mechanisms in the coagulation cascade. This report propose the novel hemostatic pad isreasonable that a great potential for excessive bleeding injury and improve effects of natural substance hemostatic pad.
Graphical abstract
http://ift.tt/2ek0xxO
Carbon nanotube-composite hydrogels promote intercalated disc assembly in engineered cardiac tissues through β1-integrin mediated FAK and RhoA pathway
Publication date: Available online 18 October 2016
Source:Acta Biomaterialia
Author(s): Hongyu Sun, Jiajia Tang, Yongchao Mou, Jing Zhou, Linlin Qu, Kayla Duval, Zhu Huang, Ning Lin, Ruiwu Dai, Chengxiao Liang, Zi Chen, Lijun Tang, Fuzhou Tian
Carbon nanotube (CNT)-based hydrogels have been shown to support cardiomyocyte growth and function. However, their role in cellular integrity among cardiomyocytes has not been studied in detail and the mechanisms underlying this process remain unclear. Here, single walled CNTs incorporated into gelatin with methacrylate anhydride (CNT/GelMA) hydrogels were utilized to construct cardiac tissues, which enhanced cardiomyocyte adhesion and maturation. Furthermore, through the use of immunohistochemical staining, transmission electron microscopy and intracellular calcium transient measurement, the incorporation of CNTs into the scaffolds was observed to markedly enhance the assembly and formation in the cardiac constructs. Importantly, we further explored the underlying mechanism behind these effects through the use of immunohistochemical staining and western blotting. The β1-integrin-mediated FAK and RhoA signaling pathways were found to be responsible for CNT-induced upregulation of electrical and mechanical junction proteins respectively. Together, our study provides new insights into the facilitative effects of CNTs on ID formation, which has important significance for improving the quality of engineered cardiac tissue and applying them to cardiac regenerative therapies.Statement of SignificanceCurrently, the bottleneck to engineering cardiac tissues (ECTs) for cardiac regeneration is the lack of efficient cellular integrity among adjacent cells, especially the insufficient remodeling of intercalated discs (IDs) in ECTs. Recently, carbon nanotube (CNT) hydrogels provide an advantageous supporting microenvironment and therefore benefit greatly the functional performance of ECTs. Although their beneficial effect in modulating ECT performance is evident, the influence of CNTs on structural integrity of ECTs has not been studied in detail, and the mechanisms underlying the process remain to be determined. Here, we utilized carbon nanotube incorporated into gelatin with methacrylate anhydride (CNT/GelMA) hydrogels to construct cardiac tissues, determined the influence of CNTs on intercalated discs (IDs) assembly and formation and explored the underlying mechanisms.
Graphical abstract
http://ift.tt/2ejZ3U8
Enzyme-mediated stiffening hydrogels for probing activation of pancreatic stellate cells
Publication date: Available online 18 October 2016
Source:Acta Biomaterialia
Author(s): Hung-Yi Liu, Tanja Greene, Tsai-Yu Lin, Camron S. Dawes, Murray Korc, Chien-Chi Lin
The complex network of biochemical and biophysical cues in the pancreatic desmoplasia not only presents challenges to the fundamental understanding of tumor progression, but also hinders the development of therapeutic strategies against pancreatic cancer. Residing in the desmoplasia, pancreatic stellate cells (PSCs) are the major stromal cells affecting the growth and metastasis of pancreatic cancer cells by means of paracrine effects and extracellular matrix protein deposition. PSCs remain in a quiescent/dormant state until they are 'activated' by various environmental cues. While the mechanisms of PSC activation are increasingly being described in literature, the influence of matrix stiffness on PSC activation is largely unexplored. To test the hypothesis that matrix stiffness affects myofibroblastic activation of PSCs, we have prepared cell-laden hydrogels capable of being dynamically stiffened through an enzymatic reaction. The stiffening of the microenvironment was created by using a peptide linker with additional tyrosine residues, which were susceptible to tyrosinase-mediated crosslinking. Tyrosinase catalyzes the oxidation of tyrosine into dihydroxyphenylalanine (DOPA), DOPA quinone, and finally into DOPA dimer. The formation of DOPA dimer led to additional crosslinks and thus stiffening the cell-laden hydrogel. In addition to systematically studying the various parameters relevant to the enzymatic reaction and hydrogel stiffening, we also designed experiments to probe the influence of dynamic matrix stiffening on cell fate. Protease-sensitive peptides were used to crosslink hydrogels, whereas integrin-binding ligands (e.g., RGD motif) were immobilized in the network to afford cell-matrix interaction. PSC-laden hydrogels were placed in media containing tyrosinase for 6 hours to achieve in situ gel stiffening. We found that PSCs encapsulated and cultured in a stiffened matrix expressed higher levels of αSMA and hypoxia-inducible factor 1α (HIF-1α), suggestive of a myofibroblastic phenotype. This hydrogel platform offers a facile means of in situ stiffening of cell-laden matrices and should be valuable for probing cell fate process dictated by dynamic matrix stiffness.Statement of SignificanceHydrogels with spatial-temporal controls over crosslinking kinetics (i.e., dynamic hydrogel) are increasingly being developed for studying mechanobiology in 3D. The general principle of designing dynamic hydrogel is to perform cell encapsulation within a hydrogel network that allows for postgelation modification in gel crosslinking density. The enzyme-mediated in situ gel stiffening is innovative because of the specificity and efficiency of enzymatic reaction. Although tyrosinase has been used for hydrogel crosslinking and in situ cell encapsulation, to the best of our knowledge tyrosinase-mediated DOPA formation has not been explored for in situ stiffening of cell-laden hydrogels. Furthermore, the current work provides a gradual matrix stiffening strategy that may more closely mimic the process of tumor development.
Graphical abstract
http://ift.tt/2ek1LZJ
Polymeric nanoparticles enable reversing macrophage in tumor microenvironment for immunotherapy
Source:Biomaterials, Volume 112
Author(s): Yi Wang, Yao-Xin Lin, Sheng-Lin Qiao, Hong-Wei An, Yang Ma, Zeng-Ying Qiao, R.P.Yeshan J. Rajapaksha, Hao Wang
Immunotherapy has shown a promising effect for a variety of cancers. However, the immune treatment efficiency of solid tumor is limited due to barely infiltration of immune cells in solid tumor. Researchers realized conversion of tumor supportive macrophages to tumor against ones was an effective method to induce the functional reverse of macrophage and contributed to the subsequent antitumor response. The current challenge in the field is that while making use of cytokines usually coupled with poor-distribution and systemic side effects. As a solution to this issue, we designed and synthesized microenvironment-responsive nanoparticles (P) with IL-12 payload (IL-12⊂P1), the IL-12⊂P1 which could adopt by systemic administration and release IL-12 in the tumor microenvironment, the local-responsive property of IL-12⊂P1 re-educate tumor-associated macrophages (TAMs) subsequently. Particularly, it illustrated great therapeutic effects which derived from functional conversion of macrophages. Our strategy was to design a microenvironment-responsive material for local macrophage reverse modification which could overcome the physiological barrier of solid tumor. The shifting of macrophages by IL-12⊂P1 realized immunomodulation in microenvironment for cancer therapy with negligible cytotoxicity. We expected that regulating the function of TAMs by pH-responsive nanomaterials would be a promising therapeutic approach for cancer immunotherapy.
http://ift.tt/2e50zY4
Synergistic thermoradiotherapy based on PEGylated Cu3BiS3 ternary semiconductor nanorods with strong absorption in the second near-infrared window
Source:Biomaterials, Volume 112
Author(s): Ang Li, Xiang Li, Xujiang Yu, Wei Li, Ruyi Zhao, Xiao An, Daxiang Cui, Xiaoyuan Chen, Wanwan Li
In this work, we report a successful synthesis of copper bismuth sulfide nanorods (NRs) with broad and strong photoabsorption ranging from ultraviolet (UV) to near-infrared (NIR) wavelengths, which can be used as a 1064 nm-laser-driven photothermal agent with the photothermal conversion efficiency of 40.7%, noticeably higher than most of the reported PTT agents working in NIR-II window. The as-prepared PEGylated Cu3BiS3 NRs were used as photoacoustic imaging (PAI) and CT imaging agents due to their strong NIR absorption and large X-ray attenuation coefficient of bismuth. We are the first to demonstrate that a small quantity of PEGylated Cu3BiS3 NRs in tumors can concentrate radiation energy and trigger mild PTT under NIR-II irradiation and thus, these particles could be used as a novel, synergistic thermoradiotheraputic agent that enhances the efficacy of radiotherapy.
http://ift.tt/2esTI8U
Micellar nanocomplexes for biomagnetic delivery of intracellular proteins to dictate axon formation during neuronal development
Source:Biomaterials, Volume 112
Author(s): Giulia Suarato, Seong-Il Lee, Weiyi Li, Sneha Rao, Tanvir Khan, Yizhi Meng, Maya Shelly
During mammalian embryonic development, neurons polarize to create distinct cellular compartments of axon and dendrite that inherently differ in form and function, providing the foundation for directional signaling in the nervous system. Polarization results from spatio-temporal segregation of specific proteins' activities to discrete regions of the neuron to dictate axonal vs. dendritic fate. We aim to manipulate axon formation by directed subcellular localization of crucial intracellular protein function. Here we report critical steps toward the development of a nanotechnology for localized subcellular introduction and retention of an intracellular kinase, LKB1, crucial regulator of axon formation. This nanotechnology will spatially manipulate LKB1-linked biomagnetic nanocomplexes (LKB1-NCs) in developing rodent neurons in culture and in vivo. We created a supramolecular assembly for LKB1 rapid neuronal uptake and prolonged cytoplasmic stability. LKB1-NCs retained kinase activity and phosphorylated downstream targets. NCs were successfully delivered to cultured embryonic hippocampal neurons, and were stable in the cytoplasm for 2 days, sufficient time for axon formation. Importantly, LKB1-NCs promoted axon formation in these neurons, representing unique proof of concept for the sufficiency of intracellular protein function in dictating a central developmental event. Lastly, we established NC delivery into cortical progenitors in live rat embryonic brain in utero. Our nanotechnology provides a viable platform for spatial manipulation of intracellular protein-activity, to dictate central events during neuronal development.
http://ift.tt/2e50YK2
Hearing Aid Batteries: The Past, Present, and Future
Modern digital hearing aids offer a huge variety of form factors, features, and wireless connectivity options that allow for individual hearing solutions. However, the price of functions like situation-based real-time processing, binaural algorithms, or streaming is an increased demand on battery performance. So far, the topic of efficient powering has received only scant attention, but this may change soon due to the many good reasons for using rechargeable batteries.
http://ift.tt/2e0qrD8
Monitoring Progression of 12 Cases of Non-Operated Middle Ear Cholesteatoma With Non-Echoplanar Diffusion Weighted Magnetic Resonance Imaging: Our Experience.
http://ift.tt/2ePTjAp
Evaluation of Rigid Cochlear Models for Measuring Cochlear Implant Electrode Position.
http://ift.tt/2ek6qHq
Diagnostic Criteria for Detection of Vestibular Schwannomas in the VA Population.
http://ift.tt/2ePQG1D
Posterior Fossa Spontaneous Cerebrospinal Fluid Leaks.
http://ift.tt/2ek8oaQ
Cochlear Implantation in the Elderly: Does Age Matter?.
http://ift.tt/2ePS58y
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- Hearing Aid Batteries: The Past, Present, and Future
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