546 research outputs found

    KT&G  : From Korean monopoly to ‘a global name in the tobacco industry’

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    Until the late 1980s, the former South Korean tobacco monopoly KT&G was focused on the protected domestic market. The opening of the market to foreign competition, under pressure from the U.S. Trade Representative, led to a steady erosion of market share over the next 10 years. Drawing on company documents and industry sources, this paper examines the adaptation of KT&G to the globalization of the South Korean tobacco industry since the 1990s. It is argued that KT&G has shifted from a domestic monopoly to an outward-looking, globally oriented business in response to the influx of transnational tobacco companies. Like other high-income countries, South Korea has also seen a decline in smoking prevalence as stronger tobacco control measures have been adopted. Faced with a shrinking domestic market, KT&G initially focused on exporting Korean-manufactured cigarettes. Since the mid-2000s, a broader global business strategy has been adopted including the building of overseas manufacturing facilities, establishing strategic partnerships and acquiring foreign companies. Trends in KT&G sales suggest an aspiring transnational tobacco company poised to become a major player in the global tobacco market. This article is part of the special issue \u27The emergence of Asian tobacco companies: Implications for global health governance\u27

    Lobster Attack Induces Sensitization In the Sea Hare, Aplysia Californica

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    Studies of the neural mechanisms of learning, especially of sensitization, have benefitted from extensive research on the model species, Aplysia californica (hereafter Aplysia). Considering this volume of literature on mechanisms, it is surprising that our understanding of the ecological context of sensitization in Aplysia is completely lacking. Indeed, the widespread use of strong electric shock to induce sensitization (an enhancement of withdrawal reflexes following noxious stimulation) is completely unnatural and leaves unanswered the question of whether this simple form of learning has any ecological relevance. We hypothesized that sublethal attack by a co-occurring predator, the spiny lobster, Panulirus interruptus, might be a natural sensitizing stimulus. We tested reflex withdrawal of the tail-mantle and head of individual Aplysia before and after attack by lobsters. Lobster attack significantly increased the amplitude of both reflexes, with a temporal onset that closely matched that observed with electric shock. This result suggests that electric shock may indeed mimic at least one naturally occurring sensitizing stimulus, suggesting, for the first time, an ecological context for this well studied form of learning

    Impact of hypercapnia on alveolar Na+-transport : Establishing a system for ENaC-protein detection

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    Acute respiratory distress syndrome is a life threatening condition triggered by a variety of pulmonary and extrapulmonary causes, that is characterized by pulmonary edema and subsequently impaired gas exchange. Due to lung protective ventilation strategies, its treatment is often associated with systemic accumulation of CO2, a condition termed permissive hypercapnia. Recent studies report a negative effect of CO2 on alveolar fluid clearance, a process mediated by its two key elements the Na+,K+-ATPase and epithelial Na+-channels (ENaCs). A reduced activity of the Na+,K+-ATPase during hypercapnia has already been demonstrated, but regulation of ENaC has never been directly linked to CO2. Many molecular signaling events that are activated during hypercapnia are known to regulate ENaC function, so the present study aimed to generate and subsequently apply techniques to investigate a possible contribution of ENaC to the reduction of alveolar epithelial fluid transport upon hypercapnia. ENaC function was studied in H441 cells by Ussing chamber experiments which revealed no significant regulation during short term hypercapnia, but a clear reduction of ENaC function during sustained hypercapnia. To identify the signaling mechanism on the molecular level, epitope-tagged human ENaC constructs for the α-, β- and γ-subunit were cloned and initially expressed in A549 cells. Exposition to hypercapnia up to 4 hours did not significantly reduce cell surface expression of the ENaC-subunits, but after 24 hours, a significant decrease of β-ENaC was observed. Since the molecular sizes of α- and γ-ENaC expressed in A549 cells were differing from previously published studies, transfection of ENaC was continued in other cells. H441 cells are commonly used for ENaC studies, so their transfection was established, yielding an efficiency of about 60 %. The molecular sizes of transfected ENaC subunits matched the pattern that was expected, but expression levels were evanescent and too low for further experiments. Since ENaC detection in these two cell lines remained problematic, a novel methodology was applied. Since the primary site of ENaC expression in the lung are epithelial cells, rat primary alveolar epithelial cells type II were used as recipients for ENaC plasmids. Non-viral transfection of ATII cells has been inefficient in the past, but during the present study a protocol was generated to efficiently deliver nucleic acids to exactly this cell type. ENaC expression was largely increased in ATII cells, compared to the cell lines used, indicating that established system might be extremely useful for further studies involving ENaC turnover. Thus, a new and highly relevant, non-viral transfection technique for primary alveolar epithelial type II cells was established, providing ground-breaking opportunities for future pulmonary research.Das Atemnotsyndrom des Erwachsenen ist eine lebensbedrohliche Erkrankung, ausgelöst durch eine Reihe von Faktoren, die direkt oder indirekt auf die Lunge einwirken . Charakteristisch für dieses Syndrom sind pulmonare Ödeme und daraus resultierend ein eingeschränkter Gasaustausch. Die daher benötigte künstliche Beatmung führt im Zuge von protektiven Beatmungsstrategien oft zu einer systemischen Anreicherung von CO2 (Hyperkapnie). Einige Studien zeigen, dass erhöhte CO2-Level den Flüssigkeitstransport der Lunge einschränken. Dieser aktive Prozess wird maßgeblich durch zwei Komponenten, die Na+,K+-ATPase und epitheliale Na+-Kanäle (ENaCs), kontrolliert. Eine Beeinträchtigung der Na+,K+-ATPase durch CO2 gezeigt, für ENaCs ist dies bislang nicht bekannt. Einige bekannte Regulatoren von ENaCs werden jedoch während Hyperkapnie aktiviert. Das Ziel der vorliegenden Arbeit war, Methoden zu etablieren und anzuwenden, die einen möglichen Einfluss von CO2 auf ENaC zeigen. Funktionelle Versuche wurden an H441-Zellen mit Ussing-Kammer-Messungen durchgeführt. Während akuter Hyperkapnie konnte keine signifikante Regulation von ENaC nachgewiesen werden, jedoch war die ENaC-Funktion bei anhaltender Hyperkapnie deutlich verringert. Um die Signalwege auf molekularer Ebene zu untersuchen, wurde die α-, β- und γ- Untereinheit des humanen ENaC kloniert, genetisch modifiziert und in A549 Zellen überexprimiert. Nach bis zu vierstündiger Hyperkapnie erfolgte keine Regulation von ENaC, jedoch wurde nach 24 Stunden eine deutlich verminderte Menge β-ENaC in der Zellmembran nachgewiesen. Da die Größen von α- und γ-ENaC von den bisher publizierten abwichen, wurden weitere Versuche in H441 Zellen durchgeführt. Die Transfektion dieser Zelllinie wurde etabliert und erreichte eine Effizienz von ungefähr 60 %. Die posttranslationale Regulation der α- und γ-Untereinheiten, insbesondere die proteolytische Aktivierung funktionierten wie in der Literatur beschrieben, jedoch waren die Expressionslevel zu gering für weitere Versuche. In der Lunge werden ENaCs überwiegend in epithelialen Zellen exprimiert. Diese Zellen konnten bisher jedoch nicht effizient transfiziert werden, ohne Viren einzusetzen. In der vorliegenden Arbeit wurde jedoch eine effiziente Methode zur Transfektion von primären epithelialen Zellen der Ratte erarbeitet. Die Expression von transfizierten ENaC-Untereinheiten war in diesen Zellen deutlich erhöht, weswegen die Etablierung dieses Systems ausschlaggebend für weitere Versuche ist. Die vorliegende Arbeit beschreibt daher zum ersten Mal die nicht-virale, effiziente Transfektion von primären alveolaren Zellen und liefert damit ein bedeutendes neues Werkzeug für die Lungenforschung

    Enhanced ozone loss by active inorganic bromine chemistry in the tropical troposphere

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    Abstract Bromine chemistry, particularly in the tropics, has been suggested to play an important role in tropospheric ozone loss (Theys et al., 2011) although a lack of measurements of active bromine species impedes a quantitative understanding of its impacts. Recent modelling and measurements of bromine monoxide (BrO) by Wang et al. (2015) have shown current models under predict BrO concentrations over the Pacific Ocean and allude to a missing source of BrO. Here, we present the first simultaneous aircraft measurements of atmospheric bromine monoxide, BrO (a radical that along with atomic Br catalytically destroys ozone) and the inorganic Br precursor compounds HOBr, BrCl and Br2 over the Western Pacific Ocean from 0.5 to 7 km. The presence of 0.17-€“1.64 pptv BrO and 3.6-8 pptv total inorganic Br from these four species throughout the troposphere causes 10-20% of total ozone loss, and confirms the importance of bromine chemistry in the tropical troposphere; contributing to a 6 ppb decrease in ozone levels due to halogen chemistry. Observations are compared with a global chemical transport model and find that the observed high levels of BrO, BrCl and HOBr can be reconciled by active multiphase oxidation of halide (Br- and Cl-ˆ’) by HOBr and ozone in cloud droplets and aerosols. Measurements indicate that 99% of the instantaneous free Br in the troposphere up to 8 km originates from inorganic halogen photolysis rather than from photolysis of organobromine species

    Trypanosoma brucei aquaglyceroporin 2 is a high-affinity transporter for pentamidine and melaminophenyl arsenic drugs and the main genetic determinant of resistance to these drugs.

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    OBJECTIVES: Trypanosoma brucei drug transporters include the TbAT1/P2 aminopurine transporter and the high-affinity pentamidine transporter (HAPT1), but the genetic identity of HAPT1 is unknown. We recently reported that loss of T. brucei aquaglyceroporin 2 (TbAQP2) caused melarsoprol/pentamidine cross-resistance (MPXR) in these parasites and the current study aims to delineate the mechanism by which this occurs. METHODS: The TbAQP2 loci of isogenic pairs of drug-susceptible and MPXR strains of T. brucei subspecies were sequenced. Drug susceptibility profiles of trypanosome strains were correlated with expression of mutated TbAQP2 alleles. Pentamidine transport was studied in T. brucei subspecies expressing TbAQP2 variants. RESULTS: All MPXR strains examined contained TbAQP2 deletions or rearrangements, regardless of whether the strains were originally adapted in vitro or in vivo to arsenicals or to pentamidine. The MPXR strains and AQP2 knockout strains had lost HAPT1 activity. Reintroduction of TbAQP2 in MPXR trypanosomes restored susceptibility to the drugs and reinstated HAPT1 activity, but did not change the activity of TbAT1/P2. Expression of TbAQP2 sensitized Leishmania mexicana promastigotes 40-fold to pentamidine and >1000-fold to melaminophenyl arsenicals and induced a high-affinity pentamidine transport activity indistinguishable from HAPT1 by Km and inhibitor profile. Grafting the TbAQP2 selectivity filter amino acid residues onto a chimeric allele of AQP2 and AQP3 partly restored susceptibility to pentamidine and an arsenical. CONCLUSIONS: TbAQP2 mediates high-affinity uptake of pentamidine and melaminophenyl arsenicals in trypanosomes and TbAQP2 encodes the previously reported HAPT1 activity. This finding establishes TbAQP2 as an important drug transporter

    ‘Sons of athelings given to the earth’: Infant Mortality within Anglo-Saxon Mortuary Geography

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    FOR 20 OR MORE YEARS early Anglo-Saxon archaeologists have believed children are underrepresented in the cemetery evidence. They conclude that excavation misses small bones, that previous attitudes to reporting overlook the very young, or that infants and children were buried elsewhere. This is all well and good, but we must be careful of oversimplifying compound social and cultural responses to childhood and infant mortality. Previous approaches have offered methodological quandaries in the face of this under-representation. However, proportionally more infants were placed in large cemeteries and sometimes in specific zones. This trend is statistically significant and is therefore unlikely to result entirely from preservation or excavation problems. Early medieval cemeteries were part of regional mortuary geographies and provided places to stage events that promoted social cohesion across kinship systems extending over tribal territories. This paper argues that patterns in early Anglo-Saxon infant burial were the result of female mobility. Many women probably travelled locally to marry in a union which reinforced existing social networks. For an expectant mother, however, the safest place to give birth was with experience women in her maternal home. Infant identities were affected by personal and legal association with their mother’s parental kindred, so when an infant died in childbirth or months and years later, it was their mother’s identity which dictated burial location. As a result, cemeteries central to tribal identities became places to bury the sons and daughters of a regional tribal aristocracy

    T Cell Cross-Reactivity and Conformational Changes during TCR Engagement

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    All thymically selected T cells are inherently cross-reactive, yet many data indicate a fine specificity in antigen recognition, which enables virus escape from immune control by mutation in infections such as the human immunodeficiency virus (HIV). To address this paradox, we analyzed the fine specificity of T cells recognizing a human histocompatibility leukocyte antigen (HLA)-A2–restricted, strongly immunodominant, HIV gag epitope (SLFNTVATL). The majority of 171 variant peptides tested bound HLA-A2, but only one third were recognized. Surprisingly, one recognized variant (SLYNTVATL) showed marked differences in structure when bound to HLA-A2. T cell receptor (TCR) recognition of variants of these two peptides implied that they adopted the same conformation in the TCR–peptide–major histocompatibility complex (MHC) complex. However, the on-rate kinetics of TCR binding were identical, implying that conformational changes at the TCR–peptide–MHC binding interface occur after an initial permissive antigen contact. These findings have implications for the rational design of vaccines targeting viruses with unstable genomes

    Modeling the System Parameters of 2M1533+3759: A New Longer-Period Low-Mass Eclipsing sdB+dM Binary

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    We present new photometric and spectroscopic observations for 2M 1533+3759 (= NSVS 07826147). It has an orbital period of 0.16177042 day, significantly longer than the 2.3--3.0 hour periods of the other known eclipsing sdB+dM systems. Spectroscopic analysis of the hot primary yields Teff = 29230 +/- 125 K, log g = 5.58 +/- 0.03 and log N(He)/N(H) = -2.37 +/- 0.05. The sdB velocity amplitude is K1 = 71.1 +/- 1.0 km/s. The only detectable light contribution from the secondary is due to the surprisingly strong reflection effect. Light curve modeling produced several solutions corresponding to different values of the system mass ratio, q(M2/M1), but only one is consistent with a core helium burning star, q=0.301. The orbital inclination is 86.6 degree. The sdB primary mass is M1 = 0.376 +/- 0.055 Msun and its radius is R1 = 0.166 +/- 0.007 Rsun. 2M1533+3759 joins PG0911+456 (and possibly also HS2333+3927) in having an unusually low mass for an sdB star. SdB stars with masses significantly lower than the canonical value of 0.48 Msun, down to as low as 0.30 Msun, were theoretically predicted by Han et al. (2002, 2003), but observational evidence has only recently begun to confirm the existence of such stars. The existence of core helium burning stars with masses lower than 0.40--0.43 Msun implies that at least some sdB progenitors have initial main sequence masses of 1.8--2.0 Msun or more, i.e. they are at least main sequence A stars. The secondary is a main sequence M5 star.Comment: 47 pages, 7 figure

    The liver X receptor pathway is highly upregulated in rheumatoid arthritis synovial macrophages and potentiates TLR-driven cytokine release

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    <p>Objectives: Macrophages are central to the inflammatory processes driving rheumatoid arthritis (RA) synovitis. The molecular pathways that are induced in synovial macrophages and thereby promote RA disease pathology remain poorly understood.</p> <p>Methods: We used microarray to characterise the transcriptome of synovial fluid (SF) macrophages compared with matched peripheral blood monocytes from patients with RA (n=8).</p> <p>Results: Using in silico pathway mapping, we found that pathways downstream of the cholesterol activated liver X receptors (LXRs) and those associated with Toll-like receptor (TLR) signalling were upregulated in SF macrophages. Macrophage differentiation and tumour necrosis factor α promoted the expression of LXRα. Furthermore, in functional studies we demonstrated that activation of LXRs significantly augmented TLR-driven cytokine and chemokine secretion.</p> <p>Conclusions: The LXR pathway is the most upregulated pathway in RA synovial macrophages and activation of LXRs by ligands present within SF augments TLR-driven cytokine secretion. Since the natural agonists of LXRs arise from cholesterol metabolism, this provides a novel mechanism that can promote RA synovitis.</p&gt
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