gebhart/patrepeval huggingface dataset:
A fresh look at tobacco harm reduction: the case for the electronic cigarette (2013)

Smokers of any age can reap substantial health benefits by quitting. In fact, no other single public health effort is likely to achieve a benefit comparable to large-scale smoking cessation. Surveys document that most smokers would like to quit, and many have made repeated efforts to do so. However, conventional smoking cessation approaches require nicotine addicted smokers to abstain from tobacco and nicotine entirely. Many smokers are unable--or at least unwilling--to achieve this goal, and so they continue smoking in the face of impending adverse health consequences. In effect, the status quo in smoking cessation presents smokers with just two unpleasant alternatives: quit or suffer the harmful effects of continuing smoking. But, there is a third choice for smokers: tobacco harm reduction. It involves the use of alternative sources of nicotine, including modern smokeless tobacco products like snus and the electronic cigarette (E-cig), or even pharmaceutical nicotine products, as a replacement for smoking. E-cigs might be the most promising product for tobacco harm reduction to date, because, besides delivering nicotine vapour without the combustion products that are responsible for nearly all of smoking's damaging effect, they also replace some of the rituals associated with smoking behaviour. Thus it is likely that smokers who switch to E-cigs will achieve large health gains. The focus of this article is on the health effects of using an E-cig, with consideration given to the acceptability, safety and effectiveness of this product as a long-term substitute for smoking.
Identification of an Aggregation-Prone Structure of Tau (2012)

The aggregation and deposition of normally soluble proteins is the hallmark of several devastating neurodegenerative disorders. For proteins such as tau in Alzheimer's disease and α-synuclein in Parkinson's disease, aggregation involves a transition from an intrinsically disordered monomer to a highly structured fiber. While understanding the role of these proteins in neurodegeneration requires elucidation of the structural basis of self-association, the conformational heterogeneity of disordered proteins makes their structural characterization inherently challenging. Here we use single molecule Förster resonance energy transfer to measure the conformational ensemble of tau in the absence and presence of heparin to identify critical conformational changes relevant to the initiation of aggregation. We find that different domains of tau display distinct conformational properties that are strongly correlated with their degree of disorder and that may relate to their roles in aggregation. Moreover, we observe that heparin binding induces a distinct two-state structural transition in tau characterized by a loss of long-range contacts and a concomitant compaction of the microtubule binding domain. Our results describe a conformational intermediate of tau that precedes the formation of aggregates and could serve as a target for tau-focused therapeutics.
Regulation in the heart field of zebrafish (1998)

In many vertebrates, removal of early embryonic heart precursors can be repaired, leaving the heart and embryo without visible deficit. One possibility is that this 'regulation' involves a cell fate switch whereby cells, perhaps in regions surrounding normal progenitors, are redirected to the heart cell fate. However, the lineage and spatial relationships between cells that are normal heart progenitors and those that can assume that role after injury are not known, nor are their molecular distinctions. We have adapted a laser-activated technique to label single or small patches of cells in the lateral plate mesoderm of the zebrafish and to track their subsequent lineage. We find that the heart precursor cells are clustered in a region adjacent to the prechordal plate, just anterior to the notochord tip. Complete unilateral ablation of all heart precursors with a laser does not disrupt heart development, if performed before the 18-somite stage. By combining extirpation of the heart precursors with cell labeling, we find that cells anterior to the normal cardiogenic compartments constitute the source of regulatory cells that compensate for the loss of the progenitors. One of the earliest embryonic markers of the premyocardial cells is the divergent homeodomain gene, Nkx2.5. Interestingly, normal cardiogenic progenitors derive from only the anterior half of the Nkx2.5-expressing region in the lateral plate mesoderm. The posterior half, adjacent to the notochord, does not include cardiac progenitors and the posterior Nkx2.5-expressing cells do not contribute to the heart, even after ablation of the normal cardiogenic region. The cells that can acquire a cardiac cell fate after injury to the normal progenitors also reside near the prechordal plate, but anterior to the Nkx2.5-expressing domain. Normally they give rise to head mesenchyme. They share with cardiac progenitors early expression of GATA 4. The location of the different elements of the cardiac field, and their response to injury, suggests that the prechordal plate supports and/or the notochord suppresses the cardiac fate.
Retinoic Acid Upregulates Ret and Induces Chain Migration and Population Expansion in Vagal Neural Crest Cells to Colonise the Embryonic Gut (2013)

Vagal neural crest cells (VNCCs) arise in the hindbrain, and at (avian) embryonic day (E) 1.5 commence migration through paraxial tissues to reach the foregut as chains of cells 1-2 days later. They then colonise the rest of the gut in a rostrocaudal wave. The chains of migrating cells later resolve into the ganglia of the enteric nervous system. In organ culture, E4.5 VNCCs resident in the gut (termed enteric or ENCC) which have previously encountered vagal paraxial tissues, rapidly colonised aneural gut tissue in large numbers as chains of cells. Within the same timeframe, E1.5 VNCCs not previously exposed to paraxial tissues provided very few cells that entered the gut mesenchyme, and these never formed chains, despite their ability to migrate in paraxial tissue and in conventional cell culture. Exposing VNCCs in vitro to paraxial tissue normally encountered en route to the foregut conferred enteric migratory ability. VNCC after passage through paraxial tissue developed elements of retinoic acid signalling such as Retinoic Acid Binding Protein 1 expression. The paraxial tissue's ability to promote gut colonisation was reproduced by the addition of retinoic acid, or the synthetic retinoid Am80, to VNCCs (but not to trunk NCCs) in organ culture. The retinoic acid receptor antagonist CD 2665 strongly reduced enteric colonisation by E1.5 VNCC and E4.5 ENCCs, at a concentration suggesting RARα signalling. By FACS analysis, retinoic acid application to vagal neural tube and NCCs in vitro upregulated Ret; a Glial-derived-neurotrophic-factor receptor expressed by ENCCs which is necessary for normal enteric colonisation. This shows that early VNCC, although migratory, are incapable of migrating in appropriate chains in gut mesenchyme, but can be primed for this by retinoic acid. This is the first instance of the characteristic form of NCC migration, chain migration, being attributed to the application of a morphogen.
Improved insulin stability through amino acid substitution (1992)

Insulin analogs designed to decrease self-association and increase absorption rates from subcutaneous tissue were found to have altered stability. Replacement of HB10 with aspartic acid increased stability while substitutions at B28 and/or B29 were either comparable to insulin or had decreased stability. The principal chemical degradation product of accelerated storage conditions was a disulfide-linked multimer that was formed through a disulfide interchange reaction which resulted from beta-elimination of the disulfides. The maintenance of the native state of insulin was shown to be important in protecting the disulfides from reduction by dithiothreitol and implicitly from the disulfide interchange reaction that occurs during storage. To understand how these amino acid changes alter chemical stability, the intramolecular conformational equilibria of each analog was assessed by equilibrium denaturation. The Gibbs free energy of unfolding was compared with the chemical stability during storage for over 20 analogs. A significant positive correlation (R2 = 0.8 and P less than 0.0005) exists between the conformational stability and chemical stability of these analogs, indicating that the chemical stability of insulin's disulfides is under the thermodynamic control of the conformational equilibria.
Estrogenic potential of progestins in oral contraceptives to stimulate human breast cancer cell proliferation. (1992)

Most oral contraceptives (OC) contain a progestin in combination with an estrogen, and the progestin component in OC includes one of the following 19-nortestosterone derivatives: norethynodrel; norethindrone; or norgestrel (levonorgestrel). It is well known that estrogens promote the growth of breast cancer. However, progestins have recently also been implicated in the development of breast cancer. We have compared and contrasted the ability of synthetic progestins to stimulate the proliferation of cultured human breast cancer cells and examined their possible mechanism of action. We found that some progestins used in OC were able to stimulate the growth of estrogen receptor-positive (ER+) MCF-7 and T47DA18 human breast cancer cells but not ER- MDA-MB-231, BT-20, and T47DC4 human breast cancer cells. However, two other progestins, MPA and R5020, which are not used in OC, were either not able to stimulate or only slightly stimulated growth. The potency of norethynodrel [median effective dose (EC50) = 4 x 10(-8) M] and norethindrone (EC50 = 3 x 10(-8) M) was greater than norgestrel (EC50 = 2 x 10(-7) M) in MCF-7 cells. E2 (EC50 = 8 x 10(-13) M) was an even more potent stimulator of growth. More importantly, the progestin-induced growth stimulation was blocked by the antiestrogens 4-hydroxytamoxifen and ICI 164,384 but not the antiprogestin 17 beta-hydroxy-11 beta-(4-dimethylaminophenyl)-17 alpha-(1-propynyl)-estra-4, 9-dien-3-one (RU486). To determine whether the proliferative action of progestins was mediated through the ER, cells were transfected with a chloramphenicol acetyltransferase reporter gene containing an estrogen response element derived from vitellogenin 2A gene. The progestins which stimulated the growth of breast cancer cells also increased chloramphenicol acetyltransferase activity. The induction of chloramphenicol acetyltransferase activity was blocked by the addition of the antiestrogens 4-hydroxytamoxifen and ICI 164,384 but not the antiprogestin RU486. This study provides direct evidence that the 19-nortestosterone derivatives in OC have estrogenic properties and suggests that activation of ER, but not progesterone receptor, is the growth-stimulatory mechanism for these synthetic progestins. Our results may help to explain the conflicting evidence linking OC and breast cancer risk. A rigorous evaluation of the "total" estrogenic potential of OC might produce a better correlation with breast cancer risk.
Circulating Levels of Soluble Klotho and FGF23 in X-Linked Hypophosphatemia: Circadian Variance, Effects of Treatment, and Relationship to Parathyroid Status (2010)

Serum klotho declines with age and demonstrates circadian variation but is normal in XLH. Serum FGF23 is similar in children and adults, is elevated in XLH, further increases with therapy, and demonstrates no diurnal variation. The direct relationship between FGF23 and PTH in subjects with XLH suggests that FGF23 regulation of PTH secretion is aberrant in this disorder.
The coming of age of tumour immunotherapy (1999)

Compared with the earlier incidence of acute infectious diseases, the introduction of vaccines has been one of the major public health success achievements. In contrast, vaccine development to control some persisting infections such as HIV remains a major challenge. There are many similarities with this task and that of controlling tumours by immunotherapy. Generating CTL responses by using pulsed dendritic cells has become a popular approach and has led to success with the mouse model. With viral antigens, priming with DNA plasmids and boosting with a chimeric live vector results in high levels of CTL activity, and is worth trying with cancer. A recent review highlights three other difficulties posed by tumours: epitope stability, maiming or killing of CTL by the tumour, and accessibility of the tumour vasculature to immune components. The new ability to label CTL by staining with specific tetrameric peptide/MHC complexes offers the possibility of effectively studying this third aspect. Our increased knowledge of tumour-associated antigens, viral or otherwise, and our growing ability to manipulate the immune system, offers hope that control of at least some human tumours may be within reach.
rAAV-CFTRΔR Rescues the Cystic Fibrosis Phenotype in Human Intestinal Organoids and Cystic Fibrosis Mice (2015)

Our study provides robust evidence that rAAV-mediated gene transfer of a truncated CFTR functionally rescues the CF phenotype across the nasal mucosa of CF mice and in patient-derived organoids. These results underscore the clinical potential of rAAV-CFTRΔR in offering a cure for all patients with CF in the future.
Expression and Tissue Concentration of Vascular Endothelial Growth Factor, Its Receptors, and Localization in the Bovine Corpus Luteum During Estrous Cycle and Pregnancy1 (2000)

The presence of vascular endothelial growth factor (VEGF) in the ovary has been reported in a number of species. The objective of the present study was to demonstrate the expression of VEGF, VEGF receptor (R)-1, and VEGFR-2 in detail by different methodological approaches in bovine corpora lutea (CL) obtained from different stages of the estrous cycle and during pregnancy. VEGF and VEGF receptor transcripts were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and ribonuclease protection assay. All components of the VEGF system were found in the bovine CL during the estrous cycle and pregnancy. Analysis of VEGF transcript by RT-PCR shows that CL tissues expressed predominantly the smallest isoforms (VEGF(121) and VEGF(165)). The highest mRNA expression for VEGF and VEGFR-2 mRNA was detected during the early luteal phase, followed by a significant decrease of expression during the mid and late luteal phase and a further decrease of VEGF mRNA after regression. During pregnancy, high levels of expression were always present. In contrast, no significant change in VEGFR-1 mRNA expression during the estrous cycle and pregnancy was found. The VEGF protein concentration in CL tissue was significantly higher (20.9-23.4 ng/g wet weight) during the early luteal phase (Days 1-7), followed by a decrease at the late luteal phase (14.3-18.7 ng/g wet weight) and, especially, after CL regression (2.8 ng/g wet weight). However, relatively high levels were found during pregnancy (10.1 ng/g wet weight). As achieved by immunohistochemistry, VEGF protein was localized predominantly in luteal cells. High VEGF protein and transcript concentrations and increased VEGFR-2 expression during the early luteal phase coincided with luteal vascularization. These results suggest an important role of VEGF in angiogenesis of the newly formed CL. The high VEGF mRNA expression and protein levels during matured vasculature in the mid-stage CL and pregnancy also suggest also a survival function for endothelial cells.
The Total Synthesis of Neomycin C (1980)

Abstract The total synthesis of the pseudo-tetrasaccharides antibiotic neomycin C is described, involving condensation of 6,3′,4′,5″-tetra-O-acetyl-1,3,2′,6′-tetra-N-(benzyloxycarbonyl)ribostamycin with 3,4-di-O-acetyl-2-deoxy-2-(p-methoxybenzylideneamino)-6-O-tosyl-α-d-glucopyranosyl bromide by a modified Koenigs-Knorr reaction.
Purification and characterization of IL6-PE4e, a recombinant fusion of interleukin 6 with Pseudomonas exotoxin (1993)

We have developed a procedure to purify the recombinant fusion toxin IL6-PE4E from Escherichia coli which results in a high yield of fully active monomeric protein of high purity and very low endotoxin content. The chimeric toxin is composed of human interleukin 6 (IL6) fused to a derivative of Pseudomonas exotoxin (PE) containing mutations in the binding domain which prevent binding to the PE receptor. In a typical preparation, 20 g of E. coli cells expressing the plasmid encoding IL6-PE4E were treated with lysozyme and washed repeatedly with detergent (Triton X-100), to obtain 500 mg of inclusion bodies. The recombinant protein was denatured and reduced in guanidine hydrochloride solution containing dithioerythritol and refolded in a redox buffer containing oxidized glutathione and L-arginine. After purification of the dialyzed protein by anion-exchange, polymyxin B, and sizing chromatography, we obtained 100 mg (20% of recombinant protein) of purified monomer with 0.6-2.5 endotoxin units/mg of protein. Amino terminal sequencing confirmed the first 20 amino acids. IL6-PE4E purified in this manner was fully cytotoxic toward human multiple myeloma, hepatoma, epidermoid carcinoma, and prostate carcinoma cell lines. After intravenous injection into mice, we found the dose-limiting toxicity to be to the liver, by measurement of serum transaminases and histologic evaluation of the liver. The LD50 was 450 micrograms/kg. We conclude that IL6-PE4E can be purified efficiently for preclinical testing.
Microfabricated Multiphase Reactors for the Direct Synthesis of Hydrogen Peroxide from Hydrogen and Oxygen (2007)

Hydrogen peroxide synthesis is demonstrated by direct combination of hydrogen and oxygen over supported palladium catalysts in a microchemical reactor. The direct combination process is chemically simple and environmentally benign for producing hydrogen peroxide, but the risk of handling the explosive gas mixture of hydrogen and oxygen over an active palladium catalyst limits implementation. By using a multichannel microchemical reactor with packed-bed catalyst, we realize the direct reaction of hydrogen and oxygen at hydrogen/oxygen ratios in the explosive regime at pressures of 2−3 MPa. As long as millimeter-sized void spaces are avoided, the microchannel structure and catalyst packaging effectively promote the heterogeneous reaction over the homogeneous free radical branching reactions that otherwise would lead to an explosion. Among the Pd/Al2O3, Pd/SiO2, and Pd/C catalysts investigated, Pd/C selectively yields hydrogen peroxide. The decomposition of peroxide is shown to be suppressed by the addition of bromide. Analysis of the microreactor data reveals significantly enhanced mass transfer relative to conventional reactors, consistent with previous multiphase microreactor studies.
Click-chemistry as an efficient synthetic tool for the preparation of novel conjugated polymers (2005)

The Cu(I)-catalysed 1,3-dipolar "click" cycloaddition is utilised as an efficient reaction for the preparation of novel fluorene-based conjugated polymers.
Dielectric frequency-selective structures incorporating waveguide gratings (2000)

In this paper, a frequency-selective structure based on guided-mode resonance effects in all-dielectric waveguide gratings is demonstrated theoretically and verified experimentally. Reflection (band-stop) filters with high efficiency, extended low-sideband reflection, and symmetric line shapes are designed by embedding gratings in layered antireflection structures. Reflection filter examples employing common dielectric materials illustrate linewidth control by grating modulation. An additional mechanism for linewidth control is demonstrated with phase-shifted gratings. Double-line reflection filters are obtained in structures containing two gratings with different grating periods. High-efficiency transmission (bandpass) filters are demonstrated using multilayer waveguide gratings in a high-reflectance thin-film configuration with a single grating in the center layer bordered by dielectric mirrors composed of high/low quarter-wave layers. Single-layer and multilayer waveguide gratings operating as reflection and transmission filters, respectively, were built and tested in the 4-20-GHz frequency range. The presence of guided-mode resonance notches and peaks is clearly established by the experimental results, and their spectral location and line shape is found to be in excellent agreement with the theoretical predictions.
Resonant fluorescent lamp converter provides efficient and compact solution (2002)

A zero voltage switched (ZVS) resonant power converter for driving cold cathode fluorescent lamps is described. Primarily intended for liquid crystal display (LCD) back lighting, the circuit features minimal component count and size. A specially designed integrated circuit provides all control functions for a current fed push-pull ZVS converter, and also contains an auxiliary pulse width modulated (PWM) controller to develop a programmable supply voltage for the LCD. Analysis and simulation of the converter, and a complete circuit schematic are presented. The analysis and simulation results are validated by experimental circuit waveforms and critical performance parameters.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>
Mammalian homologs of Drosophila ELAV localized to a neuronal subset can bind in vitro to the 3' UTR of mRNA encoding the Id transcriptional repressor (1994)

Mammalian cDNAs encoding a rat (Rel-N1) and a human (Hel-N1) neuronal RNA-binding protein have been cloned and characterized with respect to tissue specificity, neuroanatomical localization, and RNA binding specificity. Both proteins are highly similar to the product of the Drosophila elav gene, which is expressed in all neurons of the fly and is required for development of the nervous system. However, in situ hybridization of rat tissues demonstrated more restricted expression of Rel-N1 mRNA within a subset of neurons of the hippocampus, cortex, and other regions of the gray matter, but not in glial cells or white matter. In vitro RNA binding experiments demonstrated that Hel-N1 can bind to the 3' untranslated region (3' UTR) of Id mRNA, a transcript that encodes a helix-loop-helix transcriptional repressor that is abundantly expressed in undifferentiated neural precursors. Sequences characterized for Hel-N1 binding were also abundantly present in the 3' UTR of the Drosophila extramacrochaetae mRNA, which encodes an Id homolog. Thus, we have identified a potential link between a neuronal 3' UTR RNA-binding protein and regulatory transcription factors involved in neural development. These findings are interpreted in light of recent studies in which mRNA 3' UTRs were found to be important for the regulation of cell growth and differentiation.
Lipoprotein (a): impact by ethnicity and environmental and medical conditions (2015)

Levels of lipoprotein (a) [Lp(a)], a complex between an LDL-like lipid moiety containing one copy of apoB, and apo(a), a plasminogen-derived carbohydrate-rich hydrophilic protein, are primarily genetically regulated. Although stable intra-individually, Lp(a) levels have a skewed distribution inter-individually and are strongly impacted by a size polymorphism of the LPA gene, resulting in a variable number of kringle IV (KIV) units, a key motif of apo(a). The variation in KIV units is a strong predictor of plasma Lp(a) levels resulting in stable plasma levels across the lifespan. Studies have demonstrated pronounced differences across ethnicities with regard to Lp(a) levels and some of this difference, but not all of it, can be explained by genetic variations across ethnic groups. Increasing evidence suggests that age, sex, and hormonal impact may have a modest modulatory influence on Lp(a) levels. Among clinical conditions, Lp(a) levels are reported to be affected by kidney and liver diseases.