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Found 37769 matches. Displaying 4541-4550
Gleicher N, Vidali A, Braverman J, Kushnir VA, Barad DH, Hudson C, Wu YG, Wang Q, Zhang L
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Response to comment on: Gleicher N et al., 2016. Reprod biol endocrinol Sep 5; 14(1): 54

REPRODUCTIVE BIOLOGY AND ENDOCRINOLOGY 2017 APR 5; 15(?):1-2
We appreciate the interest of Tiegs et al. in our manuscript [1] but find the criticism surprising. When we wrote our paper, their abstract had been published in 2015 in Fertility& Sterility [2]. It, therefore, was appropriately referenced, while their full length manuscript, in contrast, had not yet been published and, therefore, was at the time unknown to us. The manuscript appeared only at the end of July [3]. Had we known of the manuscript we, of course, would have quoted the full length manuscript, rather than the abstract, though both in the end offered the same data set, out of a total of 525 embryo transfers, reporting on only 5 alleged clinical misdiagnoses that were reanalyzed.
Zeravcic Z, Brenner MP
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Spontaneous emergence of catalytic cycles with colloidal spheres

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2017 APR 25; 114(17):4342-4347
Colloidal particles endowed with specific time-dependent interactions are a promising route for realizing artificial materials that have the properties of living ones. Previous work has demonstrated how this system can give rise to self-replication. Here, we introduce the process of colloidal catalysis, in which clusters of particles catalyze the creation of other clusters through templating reactions. Surprisingly, we find that simple templating rules generically lead to the production of huge numbers of clusters. The templating reactions among this sea of clusters give rise to an exponentially growing catalytic cycle, a specific realization of Dyson's notion of an exponentially growing metabolism. We demonstrate this behavior with a fixed set of interactions between particles chosen to allow a catalysis of a specific six-particle cluster from a specific seven-particle cluster, yet giving rise to the catalytic production of a sea of clusters of sizes between 2 and 11 particles. The fact that an exponentially growing cycle emerges naturally from such a simple scheme demonstrates that the emergence of exponentially growing metabolisms could be simpler than previously imagined.
Roy S, Axup JY, Forsyth JS, Goswami RK, Hutchins BM, Bajuri KM, Kazane SA, Smider VV, Felding BH, Sinha SC
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SMI-Ribosome inactivating protein conjugates selectively inhibit tumor cell growth

CHEMICAL COMMUNICATIONS 2017 APR 18; 53(30):4234-4237
Cell-targeting conjugates of Saporin 6, a ribosome inactivating protein (RIP), were prepared using the Saporin Ala 157 Cys mutant, a small molecule inhibitor (SMI) of integrins alpha(v)beta(3)/alpha(v)beta(5), and a potent cytotoxin, auristatin F (AF). The conjugates selectively and potently inhibited proliferation of tumor cells expressing the target integrins. We anticipate that the small molecule-RIP bioconjugate approach can be broadly applied using other small molecule drugs.
Cohn LB, Nussenzweig MC
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HIV: Persistence through division

JOURNAL OF EXPERIMENTAL MEDICINE 2017 APR; 214(4):875-876
Bradde S, Vucelja M, Tesileanu T, Balasubramanian V
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Dynamics of adaptive immunity against phage in bacterial populations

PLOS COMPUTATIONAL BIOLOGY 2017 APR; 13(4):? Article e1005486
The CRISPR (clustered regularly interspaced short palindromic repeats) mechanism allows bacteria to adaptively defend against phages by acquiring short genomic sequences (spacers) that target specific sequences in the viral genome. We propose a population dynamical model where immunity can be both acquired and lost. The model predicts regimes where bacterial and phage populations can co-exist, others where the populations exhibit damped oscillations, and still others where one population is driven to extinction. Our model considers two key parameters: (1) ease of acquisition and (2) spacer effectiveness in conferring immunity. Analytical calculations and numerical simulations show that if spacers differ mainly in ease of acquisition, or if the probability of acquiring them is sufficiently high, bacteria develop a diverse population of spacers. On the other hand, if spacers differ mainly in their effectiveness, their final distribution will be highly peaked, akin to a "winner-take-all" scenario, leading to a specialized spacer distribution. Bacteria can interpolate between these limiting behaviors by actively tuning their overall acquisition probability.
Zhou Y, Rubinstein M, Low MJ, Kreek MJ
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Hypothalamic-specific proopiomelanocortin deficiency reduces alcohol drinking in male and female mice

GENES BRAIN AND BEHAVIOR 2017 APR; 16(4):449-461
Opioid receptor antagonist naltrexone reduces alcohol consumption and relapse in both humans and rodents. This study investigated whether hypothalamic proopiomelanocortin (POMC) neurons (producing beta-endorphin and melanocortins) play a role in alcohol drinking behaviors. Both male and female mice with targeted deletion of two neuronal Pomc enhancers nPE1 and nPE2 (nPE-/-), resulting in hypothalamic-specific POMC deficiency, were studied in short-access (4-h/day) drinking-in-the-dark (DID, alcohol in one bottle, intermittent access (IA, 24-h cycles of alcohol access every other day, alcohol vs. water in a two-bottle choice) and alcohol deprivation effect (ADE) models. Wild-type nPE+/+ exposed to 1-week DID rapidly established stable alcohol drinking behavior with more intake in females, whereas nPE-/- mice of both sexes had less intake and less preference. Although nPE-/- showed less saccharin intake and preference than nPE+/+, there was no genotype difference in sucrose intake or preference in the DID paradigm. After 3-week IA, nPE+/+ gradually escalated to high alcohol intake and preference, with more intake in females, whereas nPE-/- showed less escalation. Pharmacological blockade of mu-opioid receptors with naltrexone reduced intake in nPE+/+ in a dose-dependent manner, but had blunted effects in nPE-/- of both sexes. When alcohol was presented again after 1-week abstinence from IA, nPE+/+ of both sexes displayed significant increases in alcohol intake (ADE or relapse-like drinking), with more pronounced ADE in females, whereas nPE-/- did not show ADE in either sex. Our results suggest that neuronal POMC is involved in modulation of alcohol 'binge' drinking, escalation and 'relapse', probably via hypothalamic-mediated mechanisms, with sex differences.
Adams ZM, Fins JJ
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The historical origins of the vegetative state: Received wisdom and the utility of the text

JOURNAL OF THE HISTORY OF THE NEUROSCIENCES 2017 APR-JUN; 26(2):140-153
The persistent vegetative state (PVS) is one of the most iconic and misunderstood phrases in clinical neuroscience. Coined as a diagnostic category by Scottish neurosurgeon Bryan Jennett and American neurologist Fred Plum in 1972, the phrase vegetative first appeared in Aristotle's treatise On the Soul (circa mid-fourth century BCE). Aristotle influenced neuroscientists of the nineteenth and early-twentieth centuries, Xavier Bichat and Walter Timme, and informed their conceptions of the vegetative nervous system. Plum credits Bichat and Timme in his use of the phrase, thus putting the ancient and modern in dialogue. In addition to exploring Aristotle's definition of the vegetative in the original Greek, we put Aristotle in conversation with his contemporariesPlato and the Hippocraticsto better apprehend theories of mind and consciousness in antiquity. Utilizing the discipline of reception studies in classics scholarship, we demonstrate the importance of etymology and historical origin when considering modern medical nosology.
Brunner PM, Guttman-Yassky E, Leung DYM
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The immunology of atopic dermatitis and its reversibility with broad-spectrum and targeted therapies

JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY 2017 APR; 139(4):S65-S76
Atopic dermatitis (AD), the most common chronic inflammatory skin disease, is driven by both terminal keratinocyte differentiation defects and strong type 2 immune responses. In contrast to chronic plaque-type psoriasis, AD is now understood to be a much more heterogeneous disease, with additional activation of TH22, TH17/IL-23, and TH1 cytokine pathways depending on the subtype of the disease. In this review we discuss our current understanding of the AD immune map in both patients with early-onset and those with chronic disease. Clinical studies with broad and targeted therapeutics have helped to elucidate the contribution of various immune axes to the disease phenotype. Importantly, immune activation extends well beyond lesional AD because nonlesional skin and the blood component harbor AD-specific inflammatory changes. For this reason, future therapeutics will need to focus on a systemic treatment approach, especially in patients with moderate-to-severe disease.
Ilic N, Birsoy K, Aguirre AJ, Kory N, Pacold ME, Singh S, Moody SE, DeAngelo JD, Spardy NA, Freinkman E, Weir BA, Tsherniak A, Cowley GS, Root DE, Asara JM, Vazquez F, Widlund HR, Sabatini DM, Hahn WC
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PIK3CA mutant tumors depend on oxoglutarate dehydrogenase

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2017 APR 25; 114(17):E3434-E3443
Oncogenic PIK3CA mutations are found in a significant fraction of human cancers, but therapeutic inhibition of PI3K has only shown limited success in clinical trials. To understand how mutant PIK3CA contributes to cancer cell proliferation, we used genome scale loss-of-function screening in a large number of genomically annotated cancer cell lines. As expected, we found that PIK3CA mutant cancer cells require PIK3CA but also require the expression of the TCA cycle enzyme 2-oxoglutarate dehydrogenase (OGDH). To understand the relationship between oncogenic PIK3CA and OGDH function, we interrogated metabolic requirements and found an increased reliance on glucose metabolism to sustain PIK3CA mutant cell proliferation. Functional metabolic studies revealed that OGDH suppression increased levels of the metabolite 2-oxoglutarate (2OG). We found that this increase in 2OG levels, either by OGDH suppression or exogenous 2OG treatment, resulted in aspartate depletion that was specifically manifested as auxotrophy within PIK3CA mutant cells. Reduced levels of aspartate deregulated the malate-aspartate shuttle, which is important for cytoplasmic NAD(+) regeneration that sustains rapid glucose breakdown through glycolysis. Consequently, because PIK3CA mutant cells exhibit a profound reliance on glucose metabolism, malate-aspartate shuttle deregulation leads to a specific proliferative block due to the inability to maintain NAD(+)/NADH homeostasis. Together these observations define a precise metabolic vulnerability imposed by a recurrently mutated oncogene.
Manna PT, Obado SO, Boehm C, Gadelha C, Sali A, Chait BT, Rout MP, Field MC
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Lineage-specific proteins essential for endocytosis in trypanosomes

JOURNAL OF CELL SCIENCE 2017 APR 15; 130(8):1379-1392
Clathrin-mediated endocytosis (CME) is the most evolutionarily ancient endocytic mechanism known, and in many lineages the sole mechanism for internalisation. Significantly, in mammalian cells CME is responsible for the vast bulk of endocytic flux and has likely undergone multiple adaptations to accommodate specific requirements by individual species. In African trypanosomes, we previously demonstrated that CME is independent of the AP-2 adaptor protein complex, that orthologues to many of the animal and fungal CME protein cohort are absent, and that a novel, trypanosomerestricted protein cohort interacts with clathrin and drives CME. Here, we used a novel cryomilling affinity isolation strategy to preserve transient low-affinity interactions, giving the most comprehensive trypanosome clathrin interactome to date. We identified the trypanosome AP-1 complex, Trypanosoma brucei (Tb) EpsinR, several endosomal SNAREs plus orthologues of SMAP and the AP-2 associated kinase AAK1 as interacting with clathrin. Novel lineage-specific proteins were identified, which we designate TbCAP80 and TbCAP141. Their depletion produced extensive defects in endocytosis and endomembrane system organisation, revealing a novel molecular pathway subtending an early-branching and highly divergent form of CME, which is conserved and likely functionally important across the kinetoplastid parasites.