Quantification of crypt and stem cell evolution in the normal and neoplastic human colon.

Human intestinal stem cell and crypt dynamics remain poorly characterized because transgenic lineage-tracing methods are impractical in humans. Here, we have circumvented this problem by quantitatively using somatic mtDNA mutations to trace clonal lineages. By analyzing clonal imprints on the walls of colonic crypts, we show that human intestinal stem cells conform to one-dimensional neutral drift dynamics with a "functional" stem cell number of five to six in both normal patients and individuals with familial adenomatous polyposis (germline APC(-/+)). Furthermore, we show that, in adenomatous crypts (APC(-/-)), there is a proportionate increase in both functional stem cell number and the loss/replacement rate. Finally, by analyzing fields of mtDNA mutant crypts, we show that a normal colon crypt divides around once every 30-40 years, and the division rate is increased in adenomas by at least an order of magnitude. These data provide in vivo quantification of human intestinal stem cell and crypt dynamics.This study was supported by Cancer Research UK (to A.-M.B. and N.A.W.), the Medical Research Council (to B.C. and S.A.C.M.), the Engineering and Physical Sciences Research Council (to A.G.F.), Microsoft Research (to A.G.F.), the National Institute for Health Research University College London Hospitals Biomedical Research Centre (to M.R.J.), the Dutch Cancer Research Foundation (to M.J.), the Wellcome Trust (to B.D.S.), and Higher Education Funding Council for England (to T.A.G.)

Complete mitochondrial DNA sequences provide new insights into the Polynesian motif and the peopling of Madagascar

More than a decade of mitochondrial DNA (mtDNA) studies have given the 'Polynesian motif' renowned status as a marker for tracing the late-Holocene expansion of Austronesian speaking populations. Despite considerable research on the Polynesian motif in Oceania, there has been little equivalent work on the western edge of its expansion - leaving major issues unresolved regarding the motif's evolutionary history. This has also led to considerable uncertainty regarding the settlement of Madagascar. In this study, we assess mtDNA variation in 266 individuals from three Malagasy ethnic groups: the Mikea, Vezo, and Merina. Complete mtDNA genome sequencing reveals a new variant of the Polynesian motif in Madagascar; two coding region mutations define a Malagasy-specific sub-branch. This newly defined 'Malagasy motif' occurs at high frequency in all three ethnic groups (13-50%), and its phylogenetic position, geographic distribution, and estimated age all support a recent origin, but without conclusively identifying a specific source region. Nevertheless, the haplotype's limited diversity, similar to those of other mtDNA haplogroups found in our Malagasy groups, best supports a small number of initial settlers arriving to Madagascar through the same migratory process. Finally, the discovery of this lineage provides a set of new polymorphic positions to help localize the Austronesian ancestors of the Malagasy, as well as uncover the origin and evolution of the Polynesian motif itself

PDEPT: polymer-directed enzyme prodrug therapy

Polymer-directed enzyme prodrug therapy (PDEPT) is a novel two-step antitumour approach using a combination of a polymeric prodrug and polymer-enzyme conjugate to generate cytotoxic drug selectively at the tumour site. In this study the polymeric prodrug N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-Gly-Phe-Leu-Gly-doxorubicin conjugate PK1 (currently under Phase II clinical evaluation) was selected as the model prodrug, and HPMA copolymer-cathepsin B as a model for the activating enzyme conjugate. Following polymer conjugation (yield of 30–35%) HPMA copolymer-cathepsin B retained ~20–25% enzymatic activity in vitro. To investigate pharmacokinetics in vivo,125I-labelled HPMA copolymer-cathepsin B was administered intravenously (i.v.) to B16F10 tumour-bearing mice. HPMA copolymer-cathespin B exhibited a longer plasma half-life (free cathepsin B t1/2α= 2.8 h; bound cathepsin B t1/2α= 3.2 h) and a 4.2-fold increase in tumour accumulation compared to the free enzyme. When PK1 (10 mg kg−1dox-equiv.) was injected i.v. into C57 mice bearing subcutaneously (s.c.) palpable B16F10 tumours followed after 5 h by HPMA copolymer-cathepsin B there was a rapid increase in the rate of dox release within the tumour (3.6-fold increase in the AUC compared to that seen for PK1 alone). When PK1 and the PDEPT combination were used to treat established B16F10 melanoma tumour (single dose; 10 mg kg−1dox-equiv.), the antitumour activity (T/C%) seen for the combination PDEPT was 168% compared to 152% seen for PK1 alone, and 144% for free dox. Also, the PDEPT combination showed activity against a COR-L23 xenograft whereas PK1 did not. PDEPT has certain advantages compared to ADEPT and GDEPT. The relatively short plasma residence time of the polymeric prodrug allows subsequent administration of polymer-enzyme without fear of prodrug activation in the circulation and polymer-enzyme conjugates have reduced immunogenicity. This study proves the concept of PDEPT and further optimisation is warranted. © 2001 Cancer Research Campaign   http://www.bjcancer.co

Volume 09

Introduction Dr. Roger A. Byrne Islamic Radicalization of Women in The United Kingdom by Mackenzie Adamson Harmony by Chad Benton The Rhetoric of Distrust: A Dangerous Game During the 2016 Presidential Campaign by Garrett Badgley Neither Man nor Monster: Frankenstein\u27s Creature as Posthuman by Anna Bultrowicz Holisticrx by Kelsey Daniel Reality Bytes: Identity in the Virtual World of Ernest Cline\u27s Ready Player One by Taylor Embrey Animation by Jose Romero Sue Klebold\u27s a Mother\u27s Reckoning: A Call to Action for Mental Health Advocacy by Taylor Hughes Hillary Clinton\u27s Rhetoric of Gender Inequality: The Past, the Present, nd the (Hypothetical) Future by Haley Klepatzki Against the Grain: Eat Gluten Free by Emily Spittle Following Judith: A Midrashic Approach to the Book of Judith by Kelsey Longnaker Identity and Dialect Adaptation: The Effect of Geography and Community on Dialect by Alexis Paige Manuel These are the Gardens Of The Desert : The Revolutionary Impact Of Bryant\u27s The Prairies on American Literature by Montana Nelson Beauty is Pain: Eating Disorders, Gender, and the Lies We Feed Young Women By Faith Shelton Be a Man: The Eradication of Gender in Y: The Last Man by Joseph Stearman A Computational Study of Molecular Electronics: The Role of Molecular Structure by John Brumfield The Importance of Voting by Monica Mcgraw Method for The Detection and Removal of Antibiotics in Bottled Water by Jayden Metzger Small Chimp Print by Maddie Smith Mental Health Impairments in Rural Communities by Lyndsey Swinhart F@#* That: The Effects of Swearing and Influence of Authority on Stress Level by Amanda N. Chappell And Haley C. Moore Friend or Faux? Prosocial and Antisocial Social Media Use and Personality Traits by Samantha Burgess, Heather Dunbar, Briana Hackett, Jackie Mcmillion, Kiana Simpkins, And Ta\u27miya Vanhook-Davis There\u27s Someone in My Head but It’s Not Me : Attitudes About Diagnosis and Treatment of Psychological Disorders by Kiana Simpkins, Lindsey Sparrock, And Leonie Verstraete Efflorescent Bonds by Kristen Melton Shower Thoughts by Ryan Bultrowic

Three dimensional structure directs T-cell epitope dominance associated with allergy

<p>Abstract</p> <p>Background</p> <p>CD4+ T-cell epitope immunodominance is not adequately explained by peptide selectivity in class II major histocompatibility proteins, but it has been correlated with adjacent segments of conformational flexibility in several antigens.</p> <p>Methods</p> <p>The published T-cell responses to two venom allergens and two aeroallergens were used to construct profiles of epitope dominance, which were correlated with the distribution of conformational flexibility, as measured by crystallographic B factors, solvent-accessible surface, COREX residue stability, and sequence entropy.</p> <p>Results</p> <p>Epitopes associated with allergy tended to be excluded from and lie adjacent to flexible segments of the allergen.</p> <p>Conclusion</p> <p>During the initiation of allergy, the N- and/or C-terminal ends of proteolytic processing intermediates were preferentially loaded into antigen presenting proteins for the priming of CD4+ T cells.</p

Resistance Exercise Reverses Aging in Human Skeletal Muscle

Human aging is associated with skeletal muscle atrophy and functional impairment (sarcopenia). Multiple lines of evidence suggest that mitochondrial dysfunction is a major contributor to sarcopenia. We evaluated whether healthy aging was associated with a transcriptional profile reflecting mitochondrial impairment and whether resistance exercise could reverse this signature to that approximating a younger physiological age. Skeletal muscle biopsies from healthy older (N = 25) and younger (N = 26) adult men and women were compared using gene expression profiling, and a subset of these were related to measurements of muscle strength. 14 of the older adults had muscle samples taken before and after a six-month resistance exercise-training program. Before exercise training, older adults were 59% weaker than younger, but after six months of training in older adults, strength improved significantly (P<0.001) such that they were only 38% lower than young adults. As a consequence of age, we found 596 genes differentially expressed using a false discovery rate cut-off of 5%. Prior to the exercise training, the transcriptome profile showed a dramatic enrichment of genes associated with mitochondrial function with age. However, following exercise training the transcriptional signature of aging was markedly reversed back to that of younger levels for most genes that were affected by both age and exercise. We conclude that healthy older adults show evidence of mitochondrial impairment and muscle weakness, but that this can be partially reversed at the phenotypic level, and substantially reversed at the transcriptome level, following six months of resistance exercise training