bluuebunny/crossref_metadata_2025_split huggingface dataset:
Short-Lived Infected Cells Support Virus Replication in Sooty Mangabeys Naturally Infected with Simian Immunodeficiency Virus: Implications for AIDS Pathogenesis
Authors: Gordon Shari N. , Dunham Richard M. , Engram Jessica C. , Estes Jacob , Wang Zichun , Klatt Nichole R. , Paiardini Mirko , Pandrea Ivona V. , Apetrei Cristian , Sodora Donald L. , Lee Ha Youn , Haase Ashley T. , Miller Michael D. , Kaur Amitinder , Staprans Silvija I. , Perelson Alan S. , Feinberg Mark B. , Silvestri Guido 
Published: January 2008

ABSTRACT

Sooty mangabeys (SMs) naturally infected with simian immunodeficiency virus (SIV) do not develop AIDS despite high levels of virus replication. At present, the mechanisms underlying this disease resistance are poorly understood. Here we tested the hypothesis that SIV-infected SMs avoid immunodeficiency as a result of virus replication occurring in infected cells that live significantly longer than human immunodeficiency virus (HIV)-infected human cells. To this end, we treated six SIV-infected SMs with potent antiretroviral therapy (ART) and longitudinally measured the decline in plasma viremia. We applied the same mathematical models used in HIV-infected individuals and observed that SMs naturally infected with SIV also present a two-phase decay of viremia following ART, with the bulk (92 to 99%) of virus replication sustained by short-lived cells (average life span, 1.06 days), and only 1 to 8% occurring in longer-lived cells. In addition, we observed that ART had a limited impact on CD4
+
T cells and the prevailing level of T-cell activation and proliferation in SIV-infected SMs. Collectively, these results suggest that in SIV-infected SMs, similar to HIV type 1-infected humans, short-lived activated CD4
+
T cells, rather than macrophages, are the main source of virus production. These findings indicate that a short in vivo life span of infected cells is a common feature of both pathogenic and nonpathogenic primate lentivirus infections and support a model for AIDS pathogenesis whereby the direct killing of infected cells by HIV is not the main determinant of disease progression.
Cdc55p-Mediated E4orf4 Growth Inhibition in
Saccharomyces cerevisiae
Is Mediated Only in Part via the Catalytic Subunit of Protein Phosphatase 2A
Authors: Li Yikun , Wei Huijun , Hsieh Tung-Chin , Pallas David C. 
Published: January 2008

ABSTRACT

The adenovirus early region 4 open reading frame 4 (E4orf4) protein specifically induces p53-independent cell death of transformed but not normal human cells, suggesting that elucidation of its mechanism may provide important new avenues for cancer therapy. Wild-type E4orf4 and mutants that retain cancer cell toxicity also induce growth inhibition in
Saccharomyces cerevisiae
, which provides a genetically tractable system for studying E4orf4 function. Interaction with the protein phosphatase 2A (PP2A) B regulatory subunit is required for E4orf4's effects, suggesting that E4orf4 may function by regulating B subunit-containing heterotrimeric PP2A holoenzymes (PP2A
BAC
), which consist of a B subunit complexed with the PP2A structural (A) and catalytic (C) subunits. However, it is not known whether E4orf4-induced growth inhibition requires interaction with the PP2A C subunit or whether E4orf4 might have PP2A B subunit-dependent effects that are independent of PP2A
BAC
holoenzyme formation. To test these possibilities in
S. cerevisiae
, we disrupted the stable formation of PP2A
BAC
heterotrimers and thus E4orf4/C subunit association by PP2A C subunit point mutations or by deletion of the gene for the PP2A methyltransferase, Ppm1p, and assayed for effects on E4orf4-induced growth inhibition. Our results support a model in which E4orf4 mediates growth inhibition and cell killing both through PP2A
BAC
heterotrimers and through a B regulatory subunit-dependent pathway(s) that is independent of stable complex formation with the PP2A C subunit. They also indicate that Ppm1p has a function other than regulating the assembly of PP2A heterotrimers and suggest that selective PP2A trimer inhibitors and PP6 inhibitors may be useful as adjuvant anticancer therapies.
Identification of the Progenitors of Indonesian and Vietnamese Avian Influenza A (H5N1) Viruses from Southern China
Authors: Wang J. , Vijaykrishna D. , Duan L. , Bahl J. , Zhang J. X. , Webster R. G. , Peiris J. S. M. , Chen H. , Smith Gavin J. D. , Guan Y. 
Published: January 2008

ABSTRACT
The transmission of highly pathogenic avian influenza H5N1 virus to Southeast Asian countries triggered the first major outbreak and transmission wave in late 2003, accelerating the pandemic threat to the world. Due to the lack of influenza surveillance prior to these outbreaks, the genetic diversity and the transmission pathways of H5N1 viruses from this period remain undefined. To determine the possible source of the wave 1 H5N1 viruses, we recently conducted further sequencing and analysis of samples collected in live-poultry markets from Guangdong, Hunan, and Yunnan in southern China from 2001 to 2004. Phylogenetic analysis of the hemagglutinin and neuraminidase genes of 73 H5N1 isolates from this period revealed a greater genetic diversity in southern China than previously reported. Moreover, results show that eight viruses isolated from Yunnan in 2002 and 2003 were most closely related to the clade 1 virus sublineage from Vietnam, Thailand, and Malaysia, while two viruses from Hunan in 2002 and 2003 were most closely related to viruses from Indonesia (clade 2.1). Further phylogenetic analyses of the six internal genes showed that all 10 of those viruses maintained similar phylogenetic relationships as the surface genes. The 10 progenitor viruses were genotype Z and shared high similarity (≥99%) with their corresponding descendant viruses in most gene segments. These results suggest a direct transmission link for H5N1 viruses between Yunnan and Vietnam and also between Hunan and Indonesia during 2002 and 2003. Poultry trade may be responsible for virus introduction to Vietnam, while the transmission route from Hunan to Indonesia remains unclear.
Scavenger Receptor Class B Is Required for Hepatitis C Virus Uptake and Cross-Presentation by Human Dendritic Cells
Authors: Barth Heidi , Schnober Eva K. , Neumann-Haefelin Christoph , Thumann Christine , Zeisel Mirjam B. , Diepolder Helmut M. , Hu Zongyi , Liang T. Jake , Blum Hubert E. , Thimme Robert , Lambotin Mélanie , Baumert Thomas F. 
Published: January 2008

ABSTRACTClass B scavenger receptors (SR-Bs) bind lipoproteins and play an important role in lipid metabolism. Most recently, SR-B type I (SR-BI) and its splicing variant SR-BII have been found to mediate bacterial adhesion and cytosolic bacterial invasion in mammalian cells. In this study, we demonstrate that SR-BI is a key host factor required for hepatitis C virus (HCV) uptake and cross-presentation by human dendritic cells (DCs). Whereas monocytes and T and B cells were characterized by very low or undetectable SR-BI expression levels, human DCs demonstrated a high level of cell surface expression of SR-BI similar to that of primary human hepatocytes. Antibodies targeting the extracellular loop of SR-BI efficiently inhibited HCV-like particle binding, uptake, and cross-presentation by human DCs. Moreover, human high-density lipoprotein specifically modulated HCV-like particle binding to DCs, indicating an interplay of HCV with the lipid transfer function of SR-BI in DCs. Finally, we demonstrate that anti-SR-BI antibodies inhibit the uptake of cell culture-derived HCV (HCVcc) in DCs. In conclusion, these findings identify a novel function of SR-BI for viral antigen uptake and recognition and may have an important impact on the design of HCV vaccines and immunotherapeutic approaches aiming at the induction of efficient antiviral immune responses.
Smoking in the home and children’s health
Authors: Hill S C , Liang L 
Published: January 2008

Objectives:We estimate for young children the annual excess health service use, healthcare expenditures, and disability bed days for respiratory conditions associated with exposure to smoking in the home in the United States.Methods:Health service use, healthcare expenditures and disability bed days data come from the 1999 and 2001 Medical Expenditure Panel Survey (MEPS). Reported smoking in the home comes from the linked National Health Interview Survey, from which the MEPS sample is drawn. Multivariate statistical analysis controls for potential confounding factors. The sample is 2759 children aged 0–4.Results:Smoking in the home is associated with an increase in the probability of emergency department visits for respiratory conditions by five percentage points and the probability of inpatient use for these conditions by three percentage points. There is no relation between indoor smoking by adults and either ambulatory visits or prescription drug expenditures. Overall, indoor smoking is associated with $117 in additional healthcare expenditures for respiratory conditions for each exposed child aged 0–4. Indoor smoking is also associated with an eight percentage point increase in the probability of having a bed day because of respiratory illness for children aged 1–4.Conclusions:Despite the significant progress made in tobacco control, many children are still exposed to secondhand smoke in their home. Reducing exposure to smoking in the home would probably reduce healthcare expenditures for respiratory conditions and improve children’s health.
Differentiation of Sclerotinia minor depends on thiol redox state and oxidative stress
Authors: Patsoukis Nikolaos , Georgiou Christos D. 
Published: January 2008

Sclerotial differentiation in Sclerotinia minor is associated with oxidative stress and thiol redox state. The significance of oxidative stress to sclerotial differentiation was revealed by the higher oxidative stress of S. minor compared with a nonsclerotiogenic counterpart. The effect of thiol redox state on sclerotial differentiation was shown by the antioxidant action of the thiol (-SH) group of N-acetylcysteine and cysteine and by an unknown (not antioxidant) role of glutathione (GSH) on S. minor. The nonantioxidant role of GSH was indicated by the differentiation-inhibiting and differentiation-noninhibiting actions of the GSH biosynthesis inhibitor l-buthionine-S,R-sulfoximine and the GSH biosynthesis inducer l-2-oxo-thiazolidine-4-carboxylate, respectively, and by the increase of oxidative stress they caused during the transition from the undifferentiated to differentiated state of S. minor. Moreover, N-acetylcysteine can be used as a potent nontoxic fungicide against this phytopathogenic fungus by acting as a growth-inhibiting cytotoxic oxidant and by sustaining the fungus in the undifferentiated hyphal stage, which is vulnerable to degradation by soil microorganisms.
Metasomatism of the upper mantle beneath the Hyblean Plateau (Sicily): evidence from pyroxenes and glass in peridotite xenoliths
Authors: Perinelli C. , Sapienza G. T. , Armienti P. , Morten L. 
Published: January 2008

Abstract

Coarse-grained, protogranular spinel peridotite xenoliths in the Upper Miocene Valle Guffari diatreme display a complex history for the shallow mantle underneath the Hyblean Plateau (SE Sicily). The mineral assemblage and composition (olivine Fo
89–91
, orthopyroxene En
88–91
, Cr-diopside En
48–49
Fs
4–6
Wo
45–48
, Cr-rich spinel with cr-number=25–39) record at least one depletion event caused by melt extraction, followed by metasomatic enrichment. One of these samples (HYB40) hosts a fresh glass vein. Rare earth elements (REE) in clinopyroxenes from these peridotites show three patterns: (1) light REE-enriched (La
n
/Yb
n
=7–17); (2) spoon-shaped (La
n
/Yb
n
=18–20; La
n
/Sm
n
=21–34; Sm
n
/Yb
n
<1); (3) nearly flat (La
n
/Yb
n
∼3). Whole-rock and clinopyroxene trace elements indicate that these patterns are associated with more or less complete equilibration with at least two distinct metasomatic melts: an alkaline silicate melt resembling the host basalt and a hawaiitic melt (for peridotite HYB40).
P
–
T
estimates yield 0.9–1.2 GPa and 870–1050 °C, suggesting that refertilization by metasomatizing melts occurred at the Crust–Mantle boundary or just below. In addition, the
P
–
T
data coincide with the palaeogeotherm reported by an earlier worker that is consistent with a high geothermal gradient. However, this thermal regime does not fit with the occurrence of an active mantle plume beneath the Hyblean area because of the deduced mantle potential temperatures, which are almost 200°C lower than those typical for a mantle plume.
f
O
2
calculation gives a redox state above the fayalite–magnetite–quartz buffer FMQ (up to +1.7 Δlog units) related to melt-driven metasomatism.
Metasomatism induced by alkaline magma in the upper mantle of northern Victoria Land (Antarctica): an experimental approach
Authors: Perinelli C. , Orlando A. , Conte A. M. , Armienti P. , Borrini D. , Faccini B. , Misiti V. 
Published: January 2008

Abstract

Magma generation in the Ross Sea system is related to partial melting of strongly metasomatized mantle sources where amphibole most probably plays a crucial role. In this context, metasomatism induced by a mela-nephelinite melt in lithospheric mantle of the Mt. Melbourne Volcanic Province (northern Victoria Land (NVL), Antarctica) was investigated experimentally studying the effects of melt interaction with lherzolite at 1.5–2.0 GPa and
T
=975–1300 °C, and wehrlite at 1.0 GPa and
T
=1050–1250 °C. The experiments were designed to induce melt infiltration into the ultramafic rocks. The observed modifications in minerals are compared with those found in mantle xenoliths from NVL. The effects of metasomatic modifications are evaluated on the basis of run temperature, distance from the infiltrating melt and the diffusion rates of chemical components. Both in lherzolite and wehrlite, clinopyroxene exhibits large compositional variations ranging from primary diopside to high-Mg–Cr–(Na) augitic and omphacitic clinopyroxenes in lherzolite, and to low-Mg and high-Ti–Al–Fe–Na augites in wehrlite. Olivine (in wehrlite) and spinel (in lherzolite) are also compositionally modified: the former shows enrichment in Fe and the latter displays a higher Cr/(Cr+Al) ratio. The systematic variations in mineral compositions imply modifications of the chemistry of the infiltrating melt as recorded by the glass veinlets and patches observed in some charges. In experiments involving wehrlite paragenesis, the glass composition approaches that of melt patches associated with both amphibole-free and amphibole-bearing natural samples, and is related to olivine + clinopyroxene crystallization coupled with primary clinopyroxene dissolution at the contact between the metasomatizing melt and the solid matrix. Even if amphibole crystallization was not attained in the experiments, we were able to explain the occurrence of amphibole in the natural system considering that in this case a hot metasomatizing melt infiltrates a cooler matrix.
Reconstruction of mantle sections beneath Yakutian kimberlite pipes using monomineral thermobarometry
Authors: Ashchepkov I. V. , Pokhilenko N. P. , Vladykin N. V. , Rotman A. Y. , Afanasiev V. P. , Logvinova A. M. , Kostrovitsky S. I. , Pokhilenko L. N. , Karpenko M. A. , Kuligin S. S. , Malygina E. V. , Stegnitsky Y. B. , Alymova N. A. , Khmelnikova O. S. 
Published: January 2008

Abstract

Four original monomineral methods for mantle peridotite associations are used to reconstruct
P
–
T
conditions beneath the kimberlite pipes of Yakutia. The clinopyroxene Jd–Di method gives the closest coincidence with Opx barometry in accord with all physico-chemical boundaries. Garnet thermometers calibrated using Opx, Gar–Cpx and Ni-garnet thermometers and two variants of barometers were developed separately for pyroxenites and peridotites. A Cr–Sp thermobarometer uses the monomineralic version of the Ol–Sp thermometer and a newly calibrated Cr–Sp barometer. A picroilmenite method uses the Ol–Sp thermometer and a pressure-calibration of the geikielite component. Each mantle column is divided into two (upper and lower) sections by a pyroxenite layer located near 40 kbar. Below the pyroxenite layer, the lower section comprises 3–4 lithologically distinct horizons, with a thermally perturbed layer at the base. Above the pyroxenite layer are 3–5 lithologically distinct horizons, which are more fertile than the lower sections. Splitting of the geotherms characterizes most
P
–
T
diagrams and is ascribed to multistage melt percolation processes typical for the mantle beneath kimberlite pipes. The largest pipes are diamond-bearing and have a highly depleted peridotite lens above the asthenospheric layer.
Calcic amphiboles in peridotite xenoliths from Avacha volcano, Kamchatka, and their implications for metasomatic conditions in the mantle wedge
Authors: Ishimaru S. , Arai S. 
Published: January 2008

Abstract

Highly metasomatized parts of peridotite xenoliths from Avacha volcano, Kamchatka, Russia, characteristically contain calcic amphiboles, especially tremolites. They are rich in metasomatic pyroxenes with high Mg-number (= Mg/(Mg+Fe) atomic ratio), up to 0.94–0.98, and contain Cr-poor aluminous spinels. They have the spinel lherzolite mineral assemblage and equilibrium temperatures of 900–1000 °C or higher, beyond the stability field of tremolite. The tremolite was therefore retrogressively formed after the peak of high-temperature metasomatism. The high-Mg-number, low-alkali environment facilitates the formation of tremolite instead of Al-rich calcic amphiboles. A sulphur-bearing silicic melt derived from a slab is a probable agent involved in the metasomatism. High
f
O
2
recorded in the highly metasomatized peridotites is consistent with this process. This type of metasomatism can produce high-Mg-number peridotites and pyroxenites with low-Cr-number spinel within the mantle wedge where the Mg-number of silicates is positively correlated with the Cr-number of spinel in ambient peridotites.
Asthenospheric signature in fertile spinel lherzolites from the Viliga Volcanic Field in NE Russia
Authors: Ntaflos T. , Tschegg C. , Coltorti M. , Akinin V. V. , Kosler J. 
Published: January 2008

Abstract

Mantle xenolith bearing olivine melanephelinites from the Okhotsk sector of the Okhotsk–Chukotka Volcanic Belt (OCVB), northeastern Russia, occur as small isolated volcanoes emplaced within massive late Early to Late Cretaceous subduction-related calc-alkaline rocks. The xenoliths are typical medium- to fine‐grained anhydrous mainly spinel lherzolites that are strongly to weakly foliated with intensive to minor recrystallization to equigranular texture. The primitive mantle normalized whole-rock REE have flat patterns or patterns with slightly elevated light REE (LREE) ((La/Yb)
N
=0.48–1.38). The REE in clinopyroxenes have systematically decreasing normalized abundances from Sm to La, implying that the LREE enrichments in the whole‐rock REE patterns are attributed to circulation of minor intergranular fluids or melts. Equilibration temperatures and pressures calculated for the Viliga samples are in the range of 1050–1160 °C and 15–21 kbar, respectively. Ca diffusion rates in olivine reveal a rapid transport to the surface (2–6 days) of these peridotites. Model calculations have shown that the fertile lherzolites can be produced by 2–9% batch melting, whereas the depleted peridotites require 15% batch melting of a primitive source. The cessation of the interaction between the palaeo-Pacific plate and the NE Russian margin at
c
. 87 Ma apparently caused a ‘piecemeal’ collapse of the former followed by intrusion and ascent of olivine melanephelinitic magma, which entrained xenoliths from the asthenospheric mantle of the subducted plate during the Pliocene through the generated window(s). Moreover, clinopyroxenes that have low
87
Sr/
86
Sr and high
143
Nd/
144
Nd and plot in and above the mid-ocean ridge basalt (MORB) field are consistent with an upwelling asthenospheric mantle through the window(s) created by the ‘piecemeal’ collapse of the palaeo-Pacific plate.
Heterogeneous metasomatism in cumulate xenoliths from the Spanish Central System: implications for percolative fractional crystallization of lamprophyric melts
Authors: Orejana D. , Villaseca C. 
Published: January 2008

Abstract

The alkaline lamprophyres and diabases from the Spanish Central System carry a heterogeneous suite of xenoliths including a group of highly altered ultramafic pyroxenites that contain Cr–Mg-rich high-
T
hydrous minerals (Ti-phlogopite and pargasitic to kaersutitic amphibole), indicative of modal metasomatism. The trace element mineral compositions of these xenoliths show three patterns: type A xenoliths, with light rare earth element enriched clinopyroxenes with high field strength element (HFSE) negative anomalies; type B xenoliths, with clinopyroxenes and amphiboles with high incompatible trace element contents (large ion lithophile elements (LILE), HFSE and REE); type C xenoliths, with relatively REE- and HFSE-poor clinopyroxenes and amphiboles. These metasomatic signatures suggest the involvement of three different metasomatic agents: carbonate, silicate and hydrous fluids or melts, respectively. These agents could have been derived from the progressive differentiation of a CO
2
–H
2
O-rich highly alkaline magma, genetically related to the Late Permian alkaline magmatism. Because of the original sub-alkaline nature of the pyroxenite xenoliths, they might have been formed originally as pyroxene-rich cumulates associated with underplated Hercynian calc-alkaline basic magmas. Metasomatism as a result of the infiltration of alkaline magmas within these cumulates might explain the relatively high radiogenic Nd composition of the altered ultramafic xenoliths.
Estimating Salinity between 25° and 45°S in the Atlantic Ocean Using Local Regression
Authors: Thacker W. C. 
Published: January 2008

Abstract
The empirical relationship between salinity and temperature in the South Atlantic is quantified with the aid of local regression. To capture the spatial character of the TS relationship, models are fitted to data for each point on a three-dimensional grid with spacing of 1° in latitude, 2° in longitude, and 25 dbar in the vertical. To ensure sufficient data for statistical reliability each fit is to data from a region extending over several grid points weighted so that more remote data exert less influence than those closer to the target grid point. Both temperature and its square are used as regressors to capture the curvature seen in TS plots, and latitude and longitude are used to capture systematic spatial variations over the fitting regions. In addition to using statistics of residuals to characterize how well the models fit the data, errors for data not used in fitting are examined to verify the models’ abilities to simulate independent data. The best model overall for the entire region at all depths is quadratic in temperature and linear in longitude and latitude.