Four new neo-clerodane diterpenes from the stem bark of Croton oligandrus.

Four new neo-clerodanes, crotonolins C-F (3-6), were isolated from the stem bark of Croton oligandrus together with the known clerodane crotonzambefuran A, the abietanes 7-β-hydroxydehydroabietic acid and 7-oxodehydroabietic acid, and ferulic acid. Their structures were elucidated by spectroscopic analyses including 1D and 2D NMR and HRESIMS and by comparison with previously reported data. The cytotoxicity of the isolated compounds against A549, MCF7, PC3 and PNT2 cells was evaluated using the MTT assay. Only 7-β-hydroxydehydroabietic acid showed a moderate level of activity against PC3 cells with an IC50 value of 68.9 ± 6.6 μM

Growth inhibitory activity of biflavonoids and diterpenoids from the leaves of the Libyan Juniperus phoenicea against human cancer cells

Three biflavonoids [cupressuflavone (1), amentoflavone (2)and sumaflavone (3)], four diterpenoids [13-epi-cupressic acid (4), imbricatholic acid (5), 3-hydroxy-sandaracopimaric acid (6)and dehydroabietic acid (7)]and onelignan [β-peltatin methyl ether (8)],were isolated from the cytotoxicfractions of the extracts of the leaves of the Libyan Juniperus phoeniceaL. The structures of these compounds were elucidated by spectroscopic means.Cytotoxicity of the compounds 1-6were assessedagainst the human lung cancer cell lineA549 using the MTT assay. Compounds 1and 3showed cytotoxicityagainst the A549cells(IC50= 65 µMand 77 µM, respectively), whereas, compound 2did not show any activity. Diterpenes4-6exhibited weak cytotoxicity against the A549 cells with the IC50values of 159 µM, 263 µMand 223 µM, respectively. The cytotoxicity of each compound was compared with the anticancer drug,etoposide (IC50=61 µM).Cupressuflavone (1)wasevaluatedalso for cytotoxicity against both the human PC3 cancer cell lineand the normal prostatecell line (PNT2), and this compoundrevealed a high degreeof cytotoxic selectivity towards the prostate cancer cells (PC3), with IC50value of 19.9 µM, without any evidence of cytotoxicity towards the normal prostatecell line(PNT2)

Liquid chromatography mass spectrometry analysis and cytotoxicity of Asparagus adscendens roots against human cancer cell lines

Background: Asparagus adscendens Roxb. (Asparagaceae), is native to the Himalayas. This plant has been used in the prevention and effective treatment of various forms of cancers. Objective: This paper reports, for the first time, on the cytotoxicity of the methanol (MeOH) extract of the roots of A. adscendens and its solid‑phase extraction (SPE) fractions against four human carcinoma cell lines and LC‑ESI‑QTOF‑MS analysis of the SPE fractions. Materials and Methods: Finely powdered roots of A. adscendens were macerated in methanol and extracted through SPE using gradient solvent system (water: methanol) proceeded for analysis on LC‑ESI‑QTOF‑MS and cytotoxicity against four human carcinoma cell lines: breast (MCF7), liver (HEPG2), lung (A549), and urinary bladder (EJ138), using the 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazoliumbromide assay. Results: The MeOH extract and four SPE fractions exhibited cytotoxicity against all cell lines with the IC50 values ranging from 6 to 79 μg/mL. As observedin other Asparagus species, the presence of saponins and sapogenins in the SPE fractions was evident in the liquid chromatography‑mass spectrometry data. Conclusion: It is reasonable to assume that the cytotoxicity of the MeOH extract of the roots of A. adscendens and its SPE fractions, at least partly, due to the presence of saponins and their aglycones. This suggests that A. adscendens could be exploited as a potential source of cytotoxic compounds with putative anticancer potential

Attenuated Induction of the Unfolded Protein Response in Adult Human Primary Astrocytes in Response to Recurrent Low Glucose

This is the final version. Available on open access from Frontiers Media via the DOI in this record. The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/Supplementary Material.AIMS/HYPOTHESIS: Recurrent hypoglycaemia (RH) is a major side-effect of intensive insulin therapy for people with diabetes. Changes in hypoglycaemia sensing by the brain contribute to the development of impaired counterregulatory responses to and awareness of hypoglycaemia. Little is known about the intrinsic changes in human astrocytes in response to acute and recurrent low glucose (RLG) exposure. METHODS: Human primary astrocytes (HPA) were exposed to zero, one, three or four bouts of low glucose (0.1 mmol/l) for three hours per day for four days to mimic RH. On the fourth day, DNA and RNA were collected. Differential gene expression and ontology analyses were performed using DESeq2 and GOseq, respectively. DNA methylation was assessed using the Infinium MethylationEPIC BeadChip platform. RESULTS: 24 differentially expressed genes (DEGs) were detected (after correction for multiple comparisons). One bout of low glucose exposure had the largest effect on gene expression. Pathway analyses revealed that endoplasmic-reticulum (ER) stress-related genes such as HSPA5, XBP1, and MANF, involved in the unfolded protein response (UPR), were all significantly increased following low glucose (LG) exposure, which was diminished following RLG. There was little correlation between differentially methylated positions and changes in gene expression yet the number of bouts of LG exposure produced distinct methylation signatures. CONCLUSIONS/INTERPRETATION: These data suggest that exposure of human astrocytes to transient LG triggers activation of genes involved in the UPR linked to endoplasmic reticulum (ER) stress. Following RLG, the activation of UPR related genes was diminished, suggesting attenuated ER stress. This may be a consequence of a successful metabolic adaptation, as previously reported, that better preserves intracellular energy levels and a reduced necessity for the UPR.Diabetes UKJDRF postdoctoral fellowshipMedical Research Council (MRC)Wellcome TrustBiotechnology & Biological Sciences Research Council (BBSRC)Novo Nordisk UK Research FoundationMary Kinross Charitable TrustEuropean Foundation for the Study of Diabetes/Novo Nordisk Programm

A Kernel to Exploit Informative Missingness in Multivariate Time Series from EHRs

A large fraction of the electronic health records (EHRs) consists of clinical measurements collected over time, such as lab tests and vital signs, which provide important information about a patient's health status. These sequences of clinical measurements are naturally represented as time series, characterized by multiple variables and large amounts of missing data, which complicate the analysis. In this work, we propose a novel kernel which is capable of exploiting both the information from the observed values as well the information hidden in the missing patterns in multivariate time series (MTS) originating e.g. from EHRs. The kernel, called TCK$_{IM}$, is designed using an ensemble learning strategy in which the base models are novel mixed mode Bayesian mixture models which can effectively exploit informative missingness without having to resort to imputation methods. Moreover, the ensemble approach ensures robustness to hyperparameters and therefore TCK$_{IM}$ is particularly well suited if there is a lack of labels - a known challenge in medical applications. Experiments on three real-world clinical datasets demonstrate the effectiveness of the proposed kernel.Comment: 2020 International Workshop on Health Intelligence, AAAI-20. arXiv admin note: text overlap with arXiv:1907.0525

Cytotoxicity of the Roots of Trillium govanianum Against Breast (MCF7), Liver (HepG2), Lung (A549) and Urinary Bladder (EJ138) Carcinoma Cells.

Trillium govanianum Wall. (Melanthiaceae alt. Trilliaceae), commonly known as 'nag chhatri' or 'teen patra', is a native species of the Himalayas. It is used in various traditional medicines containing both steroids and sex hormones. In folk medicine, the rhizomes of T. govanianum are used to treat boils, dysentery, inflammation, menstrual and sexual disorders, as an antiseptic and in wound healing. With the only exception of the recent report on the isolation of a new steroidal saponin, govanoside A, together with three known steroidal compounds with antifungal property from this plant, there has been no systematic pharmacological and phytochemical work performed on T. govanianum. This paper reports, for the first time, on the cytotoxicity of the methanol extract of the roots of T. govanianum and its solid-phase extraction (SPE) fractions against four human carcinoma cell lines: breast (MCF7), liver (HEPG2), lung (A549) and urinary bladder (EJ138), using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide cytotoxicity assay and liquid chromatography and electrospray ionization quadrupole time-of-flight mass spectrometry analysis of the SPE fractions. The methanol extract and all SPE fractions exhibited considerable levels of cytotoxicity against all cell lines, with the IC50 values ranging between 5 and 16 µg/mL. Like other Trillium species, presence of saponins and sapogenins in the SPE fractions was evident in the liquid chromatography mass spectrometry data. Copyright © 2016 John Wiley & Sons, Ltd

A frequentist framework of inductive reasoning

Reacting against the limitation of statistics to decision procedures, R. A. Fisher proposed for inductive reasoning the use of the fiducial distribution, a parameter-space distribution of epistemological probability transferred directly from limiting relative frequencies rather than computed according to the Bayes update rule. The proposal is developed as follows using the confidence measure of a scalar parameter of interest. (With the restriction to one-dimensional parameter space, a confidence measure is essentially a fiducial probability distribution free of complications involving ancillary statistics.) A betting game establishes a sense in which confidence measures are the only reliable inferential probability distributions. The equality between the probabilities encoded in a confidence measure and the coverage rates of the corresponding confidence intervals ensures that the measure's rule for assigning confidence levels to hypotheses is uniquely minimax in the game. Although a confidence measure can be computed without any prior distribution, previous knowledge can be incorporated into confidence-based reasoning. To adjust a p-value or confidence interval for prior information, the confidence measure from the observed data can be combined with one or more independent confidence measures representing previous agent opinion. (The former confidence measure may correspond to a posterior distribution with frequentist matching of coverage probabilities.) The representation of subjective knowledge in terms of confidence measures rather than prior probability distributions preserves approximate frequentist validity.Comment: major revisio

Growth disrupting mutations in epigenetic regulatory molecules are associated with abnormalities of epigenetic aging.

Germline mutations in fundamental epigenetic regulatory molecules including DNA methyltransferase 3 alpha (DNMT3A) are commonly associated with growth disorders, whereas somatic mutations are often associated with malignancy. We profiled genome-wide DNA methylation patterns in DNMT3A c.2312G > A; p.(Arg771Gln) carriers in a large Amish sibship with Tatton-Brown-Rahman syndrome (TBRS), their mosaic father, and 15 TBRS patients with distinct pathogenic de novo DNMT3A variants. This defined widespread DNA hypomethylation at specific genomic sites enriched at locations annotated as genes involved in morphogenesis, development, differentiation, and malignancy predisposition pathways. TBRS patients also displayed highly accelerated DNA methylation aging. These findings were most marked in a carrier of the AML-associated driver mutation p.Arg882Cys. Our studies additionally defined phenotype-related accelerated and decelerated epigenetic aging in two histone methyltransferase disorders: NSD1 Sotos syndrome overgrowth disorder and KMT2D Kabuki syndrome growth impairment. Together, our findings provide fundamental new insights into aberrant epigenetic mechanisms, the role of epigenetic machinery maintenance, and determinants of biological aging in these growth disorders

Novel epigenetic clock for fetal brain development predicts prenatal age for cellular stem cell models and derived neurons

Induced pluripotent stem cells (iPSCs) and their differentiated neurons (iPSC-neurons) are a widely used cellular model in the research of the central nervous system. However, it is unknown how well they capture age-associated processes, particularly given that pluripotent cells are only present during the earliest stages of mammalian development. Epigenetic clocks utilize coordinated age-associated changes in DNA methylation to make predictions that correlate strongly with chronological age. It has been shown that the induction of pluripotency rejuvenates predicted epigenetic age. As existing clocks are not optimized for the study of brain development, we developed the fetal brain clock (FBC), a bespoke epigenetic clock trained in human prenatal brain samples in order to investigate more precisely the epigenetic age of iPSCs and iPSC-neurons. The FBC was tested in two independent validation cohorts across a total of 194 samples, confirming that the FBC outperforms other established epigenetic clocks in fetal brain cohorts. We applied the FBC to DNA methylation data from iPSCs and embryonic stem cells and their derived neuronal precursor cells and neurons, finding that these cell types are epigenetically characterized as having an early fetal age. Furthermore, while differentiation from iPSCs to neurons significantly increases epigenetic age, iPSC-neurons are still predicted as being fetal. Together our findings reiterate the need to better understand the limitations of existing epigenetic clocks for answering biological research questions and highlight a limitation of iPSC-neurons as a cellular model of age-related diseases

Teaching Medicine to Non-English Speaking Background Learners in a Foreign Country

Teaching abroad exposes medical educators to unfamiliar teaching methods and learning styles that can enhance their overall teaching repertoire. Based on the author’s experience teaching residents for one month at a community hospital in Japan and a review of the non-English speaking background (NESB) educational literature, pedagogical principles and lessons for successful international NESB instruction are outlined. These methods include understanding the dissimilar linguistic, cultural, and academic backgrounds of the learners, emphasizing pace and clarity of speech, presenting a conceptual framework instead of detailed discourse on subjects, and regular visual reinforcement of spoken words. The limitations introduced by the language barrier and the use of interpreters are briefly discussed. As society and institutions of higher learning become more global and multicultural, clinician–educators may benefit from teaching in other countries in order to enhance their teaching skills with NESB learners, both abroad and in their own institutions