Substrates mimicking the blastocyst geometry revert pluripotent stem cell to naivety.

Naive pluripotent stem cells have the highest developmental potential but their in vivo existence in the blastocyst is transient. Here we report a blastocyst motif substrate for the in vitro reversion of mouse and human pluripotent stem cells to a naive state. The substrate features randomly varied microstructures, which we call motifs, mimicking the geometry of the blastocyst. Motifs representing mouse-blastocyst-scaled curvature ranging between 15 and 62 mm-1 were the most efficient in promoting reversion to naivety, as determined by time-resolved correlative analysis. In these substrates, apical constriction enhances E-cadherin/RAC1 signalling and activates the mechanosensitive nuclear transducer YAP, promoting the histone modification of pluripotency genes. This results in enhanced levels of pluripotency transcription factor NANOG, which persist even after cells are removed from the substrate. Pluripotent stem cells cultured in blastocyst motif substrates display a higher development potential in generating embryoid bodies and teratomas. These findings shed light on naivety-promoting substrate design and their large-scale implementation.

Targeting MDM2-p53 interaction in Glioblastoma: Transcriptomic analysis and Peptide-Based inhibition strategy.

MDM2 is a gene that encodes a protein involved in cell survival, growth, and DNA repair. It has been implicated in the development and progression of glioblastoma (GBM). Inhibition of the MDM2-p53 interaction has emerged as a promising strategy for treating GBM. In this study, we performed comprehensive transcriptomic expression analysis from diverse datasets and observed MDM2 overexpression in a subset of GBM cases. MDM2 negatively regulates the major onco-suppressor p53. The interaction between MDM2 and p53 is a promising target for cancer therapy, as it can trigger p53-mediated cell death in response to different stress conditions, such as oncogene activation or DNA damage. In this study, we have identified a peptide-based inhibition of MDM2 as a therapeutic strategy for GBM. We have further validated the stability of the MDM2-peptide interaction using a molecular structural dynamics approach. The major trajectories, including root mean square of deviation (RMSD), root mean square of fluctuation (RMSF), and radius of gyration (RoG), indicate that the candidate peptides have a more stable binding compared to the native ligand and control drug. The stability of the binding interaction was further estimated by MMGBSA analysis, which also suggests that MDM2 has a stable binding with both peptide molecules. Based on these results, peptides P-1843 and P-3837 could be tested further for experimental validation to confirm their targeted inhibition of MDM-2. This approach could provide a highly selective and efficient inhibitor with potentially fewer side effects and less toxicity compared to small drug-based molecules.

Macrophage mannose receptor CD206 targeting of fluoride-18 labeled mannosylated dextran: A validation study in mice.

PURPOSE: Aluminum fluoride-18-labeled 1,4,7-triazacyclononane-1,4,7-triacetic acid-conjugated mannosylated dextran derivative (Al[18F]F-NOTA-D10CM) is a new tracer for PET imaging. We report here on in vitro and in vivo validation of the tracer's ability to target the macrophage mannose receptor CD206. METHODS: First, the uptake of intravenously (i.v.) administered Al[18F]F-NOTA-D10CM was compared between wild-type (WT) and CD206-/- knockout (KO) mice. C57BL/6N mice were injected with complete Freund's adjuvant (CFA) in the left hind leg and the uptake of Al[18F]F-NOTA-D10CM after i.v. or intradermal (i.d.) injection was studied at 5 and 14 days after CFA induction of inflammation. Healthy C57BL/6N mice were studied as controls. Mice underwent PET/CT on consecutive days with [18F]FDG, i.v. Al[18F]F-NOTA-D10CM, and i.d. Al[18F]F-NOTA-D10CM. After the last imaging, Al[18F]F-NOTA-D10CM was i.v. injected for an ex vivo biodistribution study and autoradiography of inflamed tissues. Blood plasma samples were analyzed using high-performance liquid chromatography. To evaluate the specificity of Al[18F]F-NOTA-D10CM binding, an in vitro competitive displacement study was performed on inflamed tissue sections using autoradiography. CD206 expression was assessed by immunohistochemical staining. RESULTS: Compared with WT mice, the uptake of Al[18F]F-NOTA-D10CM was significantly lower in several CD206-/- KO mice tissues, including liver (SUV 8.21 ± 2.51 vs. 1.06 ± 0.16, P < 0.001) and bone marrow (SUV 1.63 ± 0.37 vs. 0.22 ± 0.05, P < 0.0001). The uptake of i.v. injected Al[18F]F-NOTA-D10CM was significantly higher in inflamed ankle joint (SUV 0.48 ± 0.13 vs. 0.18 ± 0.05, P < 0.0001) and inflamed foot pad skin (SUV 0.41 ± 0.10 vs. 0.04 ± 0.01, P < 0.0001) than in the corresponding tissues in healthy mice. The i.d.-injected Al[18F]F-NOTA-D10CM revealed differences between CFA-induced lymph node activation and lymph nodes in healthy mice. Ex vivo γ-counting, autoradiography, and immunohistochemistry supported the results, and a decrease of ~ 80% in the binding of Al[18F]F-NOTA-D10CM in the displacement study with excess NOTA-D10CM confirmed that tracer binding was specific. At 60 min after i.v. injection, an average 96.70% of plasma radioactivity was derived from intact Al[18F]F-NOTA-D10CM, indicating good in vivo stability. The uptake of Al[18F]F-NOTA-D10CM into inflamed tissues was positively associated with the area percentage of CD206-positive staining. CONCLUSION: The uptake of mannosylated dextran derivative Al[18F]F-NOTA-D10CM correlated with CD206 expression and the tracer appears promising for inflammation imaging.

In Vivo Imaging of [60]Fullerene-Based Molecular Spherical Nucleic Acids by Positron Emission Tomography.

18F-Labeled [60]fullerene-based molecular spherical nucleic acids (MSNAs), consisting of a human epidermal growth factor receptor 2 (HER2) mRNA antisense oligonucleotide sequence with a native phosphodiester and phosphorothioate backbone, were synthesized, site-specifically labeled with a positron emitting fluorine-18 and intravenously administrated via tail vein to HER2 expressing HCC1954 tumor-bearing mice. The biodistribution of the MSNAs was monitored in vivo by positron emission tomography/computed tomography (PET/CT) imaging. MSNA with a native phosphodiester backbone (MSNA-PO) was prone to rapid nuclease-mediated degradation, whereas the corresponding phosphorothioate analogue (MSNA-PS) with improved enzymatic stability showed an interesting biodistribution profile in vivo. One hour after the injection, majority of the radioactivity was observed in spleen and liver but also in blood with an average tumor-to-muscle ratio of 2. The prolonged radioactivity in blood circulation may open possibilities to the targeted delivery of the MSNAs.

A review on extraction, composition, structure, and biological activities of polysaccharides from different parts of Nelumbo nucifera.

Nelumbo nucifera (lotus plant) is an important member of the Nelumbonaceae family. This review summarizes the studies conducted on it since the past 15 years to provide an understanding on future areas of focus. Different parts of this plant, that is, leaves, roots, and seeds, have been used as food and for the treatment of various diseases. Polysaccharides have been extracted from different parts using different methods. The manuscript reviews the methods of extraction of polysaccharides used for leaves, roots, and seeds, along with their yield. Some methods can provide better yield while some provide better biological activity with low yield. The composition and structure of extracted polysaccharides have been determined in some studies. Although monosaccharide composition has been determined in various studies, too little information about the structure of polysaccharides from N. nucifera is available in the current literature. Different useful biological activities have been explored using in vivo and in vitro methods, which include antioxidant, antidiabetic, antitumor, anti-osteoporotic, immunomodulatory, and prebiotic activities. Antitumor activity from polysaccharides of lotus leaves is yet to be explored, besides lotus root has been underexplored as compared to other parts (leaves and seeds) according to our literature survey. Studies dedicated to the successful use of combination of extraction methods can be conducted in future. The plant provides a therapeutic as well as nutraceutical potential; however, antimicrobial activity and synergistic relationships of polysaccharides from different parts of the plant need further exploration.

Automated multi-class classification of skin lesions through deep convolutional neural network with dermoscopic images.

As an analytic tool in medicine, deep learning has gained great attention and opened new ways for disease diagnosis. Recent studies validate the effectiveness of deep learning algorithms for binary classification of skin lesions (i.e., melanomas and nevi classes) with dermoscopic images. Nonetheless, those binary classification methods cannot be applied to the general clinical situation of skin cancer screening in which multi-class classification must be taken into account. The main objective of this research is to develop, implement, and calibrate an advanced deep learning model in the context of automated multi-class classification of skin lesions. The proposed Deep Convolutional Neural Network (DCNN) model is carefully designed with several layers, and multiple filter sizes, but fewer filters and parameters to improve efficacy and performance. Dermoscopic images are acquired from the International Skin Imaging Collaboration databases (ISIC-17, ISIC-18, and ISIC-19) for experiments. The experimental results of the proposed DCNN approach are presented in terms of precision, sensitivity, specificity, and other metrics. Specifically, it attains 94 % precision, 93 % sensitivity, and 91 % specificity in ISIC-17. It is demonstrated by the experimental results that this proposed DCNN approach outperforms state-of-the-art algorithms, exhibiting 0.964 area under the receiver operating characteristics (AUROC) in ISIC-17 for the classification of skin lesions and can be used to assist dermatologists in classifying skin lesions. As a result, this proposed approach provides a novel and feasible way for automating and expediting the skin lesion classification task as well as saving effort, time, and human life.

A review on polysaccharides from Artemisia sphaerocephala Krasch seeds, their extraction, modification, structure, and applications.

Artemisia sphaerocephala Krasch (ASK) is an important member of Compositae (Asteraceae) family. Its seeds have been widely used as traditional medicine and to improve the quality of food. Water soluble and water insoluble polysaccharides are found in the seeds of this plant. Research has been conducted on the extraction of polysaccharides, their modification and determination of their structure. To date different techniques for extraction purposes have been applied which are reviewed here. Antioxidant, antidiabetic, anti-obesogenic, antitumor, and immunomodulatory activities have been explored using in vivo and in vitro methods. Moreover, these polysaccharides have been used as packaging material and as a sensing component for monitoring the freshness of packaged food. Some experimental results have shown that the quality of foods is also improved by using them as a food additive. We have also indicated some of the potential areas that are needed to be explored.

Attributes of successfully matched versus unmatched obstetrics and gynecology fellowship applicants.

OBJECTIVE: We sought to determine the attributes of successful and unsuccessful fellowship applicants of the American Board of Obstetrics and Gynecology Inc (ABOG)-approved fellowship programs and to identify salient differences between subspecialty applicants. STUDY DESIGN: Anonymous questionnaires were completed by obstetrics and gynecology fellowship applicants using a web-based survey after match day of 2012. Fellowship applicant practices were evaluated and included importance of prematch preparations, interview process, networking practices, and postmatch reflections. RESULTS: A total of 327 fellowship applicants applying to programs accredited by the ABOG were surveyed, and 200 completed the survey (61% response rate). A comparison between prematch educational preparations pursued by applicants showed that matched applicants were more likely to come from allopathic medical schools (94%), attain membership in Alpha Omega Alpha and/or Phi Beta Kappa (27%), and receive a letter of recommendation from a nationally known subspecialist (77%) than unmatched applicants (P = .03, .005, and .007, respectively). Applicants to reproductive endocrinology and infertility were more likely than female pelvic medicine and reconstructive surgery to be members of academic honor societies (P = .008). Research publication was common among matched subspecialist applicants, with over half publishing 1-3 peer-reviewed manuscripts prior to matching. Applicants to gynecologic oncology did more visiting electives than any other specialty applicants (P < .001). CONCLUSION: Successful obstetrics and gynecology fellowship applicants have superior prematch preparations, strong letters of recommendation from leaders in their field of interest, and multiple research publications. These data will guide applicants to a critical self-analysis before deciding to apply.

Assessment of four tissue models on knot tensile strength.

OBJECTIVE: To determine whether the tissue model onto which a knot is tied influences the knot's tensile strength. STUDY DESIGN: Zero-gauge, nonexpired, silk, polyglactin 910, polydioxanone, and polypropylene sutures were tied on 4 different mock tissue models. The tissue models were standard metal hex head screw, uncooked chicken breast, a tube of packaged "string" cheese, and a cylinder of bubble wrap. The knots were tied without a surgeon's knot and with 4 additional square knots (1 = 1 = 1 = 1 = 1). The knots were tied by a single obstetrician/gynecologist investigator (J.M.D.) over the period of 1 week to minimize fatigue. We compared the knots when subjected to a tensiometer until the suture broke or untied. A minimum of 20 knots per group were needed to detect a moderate effect size with a power of 85% and a type I error rate of 5%. RESULTS: A total of 407 knots were tied with 4 types of material (silk, polyglactin 910, polydioxanone, and polypropylene), using 4 different models (chicken, bubble wrap, cheese, and metal). Among the knot failures, 113 of 407 untied rather than broke (28%). No differences in the likelihood of knots coming untied between the different models (p = 0.34) or tension at failure (p = 0.81) were noted. A 4 × 4 factorial analysis of variance (ANOVA) was conducted to determine the effects of the suture material and model type on tension at failure and whether there was any interaction between the 2 factors. No significant difference was observed in the interaction between suture material and model type (p = 0.35), and no effect for model type was found (p = 0.22). CONCLUSIONS: Tissue models that use materials more similar to human tissue do not seem to influence knot strength when compared with standard metal models. We propose that it is possible to have an accurate understanding of how knots withstand force and to simulate an in vivo environment by using low-cost, easily accessible natural and synthetic materials for the mechanism onto which the knot is tied.

Minimum number of throws needed for knot security.

OBJECTIVE: The purpose of the study was to determine the optimal number of throws to ensure knot security. STUDY DESIGN: Knots were tied with 3, 4, 5, or 6 square throws with 0-gauge coated polyester, polydioxanone, polypropylene, and polyglactin 910. The suture was soaked in 0.9% sodium chloride and subsequently transferred to a tensiometer and broken. RESULTS: A total of 225 knots were tied. Regardless of the suture type, tension at failure for knots with 4 throws, 5 throws, and 6 throws was higher than tension at failure of knots with only 3 throws (p < 0.05 for each). We found no difference in the tensile strength between knots with 4, 5, or 6 throws (p > 0.05 for each). Knots with 4 throws were significantly more likely to come untied than knots with 5 or 6 throws (p < 0.01). CONCLUSIONS: Under laboratory conditions, the ideal knot has 5 throws to maximize tensile strength and rate of untying. This finding does not seem to vary by type of suture material.

Risk: benefit profile of etanercept in elderly patients with rheumatoid arthritis, ankylosing spondylitis or psoriatic arthritis.

Rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) are commonly thought of as inflammatory diseases that affect younger individuals. Although the initial presentation of these diseases is commonly in a patient's twenties or thirties, they usually persist for the duration of the patient's life. In addition, up to one-third of patients with RA have disease onset after 60 years of age. Older patients with any of these three diseases are more likely to have more severe disease with significant functional decline. They are also more likely to have co-morbid diseases and use concomitant medications than patients who are younger. In patients with RA, AS or PsA, the introduction of anti-tumour necrosis factor (TNF)-alpha therapies such as etanercept, infliximab and adalimumab has had a significant impact in ameliorating the signs and symptoms of disease, improving patient function and inhibiting radiographic progression. Anti-TNFalpha therapies now have well recognised safety profiles that have been demonstrated in the usual clinical trial populations for these diseases, but such populations under-represent patients > or =65 years of age. This review explores the information currently available regarding patients aged > or =65 years treated with anti-TNFalpha therapies for RA, AS or PsA, focusing on etanercept in RA because of a lack of data for other therapies and conditions. The analyses conducted show that there is similar efficacy in the treatment of RA in patients <65 years old and those > or =65 years of age. Although there are some differences in the adverse events noted in these two age groups, it appears as though treatment of patients > or =65 years of age, compared with age-matched controls, is not dissimilar to treatment of patients <65 years of age compared with their age-matched controls. Only by understanding the risks and benefits of therapy in the older age group can a true risk : benefit profile for etanercept, and ultimately other anti-TNFalpha therapies, be determined by the practising physician and the patient.

Considerations with the use of biological therapy in the treatment of rheumatoid arthritis.

The treatment of rheumatoid arthritis (RA) has changed dramatically over the past 15 years with the realisation that earlier, aggressive therapy limits progression. There is evidence that biological response modifiers (BRMs), which target specific cytokines such as TNF-alpha and IL-1, are more effective than traditional disease-modifying antirheumatic drugs (DMARDs), especially in combination with methotrexate. Four therapies are approved for use in RA; three target TNF-alpha (etanercept [Enbrel, Amgen Inc.], infliximab [Remicade, Centocor Inc.], and adalimumab [Humira, Abbott]), and one targets IL-1 (anakinra [Kineret, Amgen Inc.]). It is clear from both the clinical trials and postmarketing reports that all four agents have a different safety profile compared with traditional DMARDs. There are several areas of concern with the use of the BRMs, which include serious and opportunistic infections, malignancy/lymphoma, congestive heart failure, demyelination, injection/infusion reactions, development of autoantibodies and lupus-like disease. It is important to be fully aware of the safety profile and differences between BRMs in order to use them appropriately.

Safety and efficacy of disease-modifying anti-rheumatic agents: focus on the benefits and risks of etanercept.

The traditional approach to the treatment of rheumatoid arthritis (RA) has been the use of nonsteroidal anti-inflammatory drugs usually in combination with a disease-modifying antirheumatic drug (DMARD) such as hydroxychloroquine, gold, sulfasalazine, methotrexate, leflunomide or cyclosporin. Each of these DMARDs has its own distinct toxicities but has also been shown to be effective in reducing signs and symptoms of disease and to some extent, reduce radiological progression. Within the past 10 years, the combination of several traditional DMARDs has been shown to have increased efficacy over monotherapy without a significant increase in toxicity in a majority of studies. Recently, the US Food and Drug Administration has approved infliximab, a chimeric monoclonal antibody to tumour necrosis factor (TNF)-alpha in combination with methotrexate, for the treatment of signs and symptoms of RA, delay of radiological progression of disease and improvement of physical function while anakinra, an interleukin-1 receptor antagonist, has been approved for the treatment of the signs and symptoms of RA either as monotherapy or in combination with methotrexate. Etanercept is the first biological response modifier approved for use in RA in the US. Double-blind, randomised controlled studies have shown etanercept to be effective therapy in patients with RA who have had inadequate response to DMARDs, in combination with methotrexate, and as early monotherapy. Similar results were seen in juvenile and psoriatic arthritis in DMARD nonresponders. Open-label studies have shown efficacy in adult Still's disease, ankylosing spondylitis, progressive systemic sclerosis, Wegener's granulomatosis and chronic uveitis. Safety issues are a concern because of the ubiquitous role of TNF. To date the only consistent adverse event seen with etanercept has been injection site reactions. Infections occur at the same rate and with the same frequency as the placebo population. There should be caution, however, with using etanercept in patients with a serious infection, or recurrent infections or patients with untreated or latent tuberculosis. As of yet there has not been seen an increase of malignancies. Rare neurological and haematological events have been noted. Etanercept has been a significant addition to the armamentarium of medications for the treatment of RA, juvenile and psoriatic arthritis. Preliminary data show that it may be well tolerated and effective in other rheumatic diseases in which there is over production of TNFalpha.