Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago.

The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200-800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700-50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.

A solid phase extraction-liquid chromatographic-tandem mass spectrometry method for determination of concentrations of GDC-0941, a small molecule class I phosphatidylinositide 3-kinase inhibitor, to support clinical development.

A solid phase extraction (SPE) liquid chromatographic-tandem mass spectrometry (LC-MS/MS) method for the determination of GDC-0941 concentrations in human plasma has been developed and validated to support clinical development. An Oasis MCX 10mg 96-well SPE plate was used to extract plasma samples (50 µL) and the resulting extracts were analyzed using reverse-phase chromatography and mass spectrometer coupled with a turbo-ionspray interface. The method was validated over the calibration curve range 0.500-500 ng/mL with linear regression and 1/x(2) weighting. Within-run relative standard deviation (%RSD) ranged from 1.5 to 11.5%, while the between-run %RSD varied from 0.0 to 4.4%. The accuracy ranged from 96.0% to 110.0% of nominal for within-run and 98.0% to 108.0% of nominal for between-run at all concentrations including the LLOQ quality control at 0.500 ng/mL. Extraction recovery of GDC-0941 was between 79.0% and 86.2%. Stability of GDC-0941 was established in human plasma for 602 days at -70 °C and 598 days at -20°C, respectively, and established in reconstituted sample extracts for 167 h when stored at room temperature. Internal standard normalized matrix factor was 1.1, demonstrating that the use of the stable-labeled internal standard GDC-0941-d(8) effectively compensated observed matrix effect and resulting in no adverse impact on the quality of the data produced. This assay was used for the determination of GDC-0941 human plasma concentrations over a sufficient time period to determine pharmacokinetic parameters at relevant clinical doses.

The course of hepatitis C viraemia in transfusion recipients prior to availability of antiviral therapy.

Knowing the likely distribution of intervals from hepatitis C infection to first RNA-negativity is important in deciding about therapeutic intervention. Prospectively collected sera and data from the Transfusion-transmitted Viruses Study (1974-1980) provide specific dates of infection and pattern of alanine aminotransferase (ALT) elevations. We examined frequency, timing and correlates of spontaneous resolution for 94 acutely infected transfusion recipients followed for a median of 9.5 months. Later, follow-up sera (>10 years) were available for 27 of the 94 cases from a Veterans Administration (VA) Study (1989-1990). Twenty-five (27%) of the 94 cases were classified as probably resolved during the episode itself. First RNA negativity occurred at 6-50 weeks (median, 19.5 weeks) after infection, and 5-43 weeks (median, 11 weeks) after ALT elevation. Thirteen of the 25 cases remained RNA-negative subsequently; 12 others had 1-6 RNA-positive sera intercalated between first and last RNA-negative results. RNA negativity, therefore, began variably and was interrupted in 12 cases of 25 (48%) by transient RNA-positive sera. Five of these 25 patients who were RNA-negative in the last study specimen had late, Veterans Administration Study follow-up; none showed viraemia. Of the remaining 69 transfusion transmitted virus study recipients, whose last serum was RNA-positive, two cleared viraemia after the last study serum but before late follow-up. Eleven (16%) had 23 intercalated RNA-negative sera before last positivity. RNA status, therefore, needs monitoring for many months before judging the spontaneous outcome as transient negativity may occur. Resolution was significantly more common in women and symptomatic cases; it was not associated with viral load in the infectious donation, HCV genotype, or the recipient's age.

Antibodies to a novel antigen in acute hepatitis C virus infections.

BACKGROUND: Conformational viral proteins potentially play an important role in the immunobiology of acute hepatitis C virus (HCV) infection and may enable earlier antibody detection. MATERIALS AND METHODS: HCV RNA was detected using nucleic acid testing. Early antibody production was evaluated using three enzyme immunoassays (EIAs) containing antigenic proteins not present in licensed EIAs. Respectively, these contained: (1) multiple-epitope fusion antigen (MEFA) 7.1-NS3/4a, (2) F and Core, and (3) E1/E2 proteins. NS3/4a is a conformational antigen retaining protease and helicase enzymatic activities. MEFA 7.1 contains the linear epitopes used in licenced EIAs, including the latest EIA-3.0, in combination with genotype 1-3 specific epitopes. Forty-two RNA positive, EIA-3.0 negative samples, including two persistently serosilent cases, were used to evaluate these research EIAs. As controls, 54 EIA-3.0 negative/RNA negative and three HCV RNA+/antibody positive specimens were included. RESULTS: Only the MEFA 7.1-NS3/4a EIA was positive in seven (17%) of the 42 HCV RNA + specimens, in all three EIA-3.0 positive controls but in none of 54 EIA-3.0 negative/HCV RNA negative controls. Notably, six of the seven (86%) specimens had evidence of active hepatitis (ALT > 210 IU/l). The two serosilent cases were research EIA negative. CONCLUSION: A novel EIA with conformational and linear epitopes detected HCV antibodies in 17% of viraemic specimens missed by the standard reference EIA-3.0. Our research EIA appears to detect HCV antibodies closer to the initiation of acute hepatitis. Given that the average RNA-positive, antibody-negative window period is 56.4 days, this 17% yield would translate into a 10-day earlier detection of antibodies.

Performance of ORTHO HCV core antigen and trak-C assays for detection of viraemia in pre-seroconversion plasma and whole blood donors.

OBJECTIVE: Logistics and cost of nucleic acid amplification testing (NAT) screening preclude its current use in many developing countries. Development of hepatitis C virus (HCV) core antigen assays offer an alternative to NAT. We evaluated two specimen populations to assess the sensitivity, relative to NAT, of the HCV core antigen (HCVcAg) ELISA (enzyme-linked immunosorbent assay) test system and the trak-C assay: (1) plasma donor HCV NAT-conversion panels and (2) cross-sectional whole blood donor NAT yield specimens. METHODS: Differential sensitivities among NAT (NGI; Chiron/Gen-Probe) and both HCVcAg assays (Ortho-Clinical Diagnostics, Rochester, NY) were evaluated using: (1) 102 serial ramp-up phase specimens from 37 plasma donor NAT-conversion panels (Alpha Therapeutic/BioClinical Partners); and (2) 42 cross-sectional whole blood donor NAT yield specimens (confirmed RNA positive, antibody negative) plus 54 NAT false-positive specimens (American Red Cross). RESULTS: Viral load among the plasma donor NAT-conversion panels at the cutoffs for HCVcAg and trak-C assays were 32 000 copies/ml (95% confidence interval [CI] 8000-120 000) and 8000 copies/ml (95% CI: 2200-28 000), respectively. The mean (95% CI) difference in window period reduction compared to routine mini-pool NAT screening (estimated sensitivity 100 copies/ml) was delayed 5.2 days (2.2-7.6 days) for HCVcAg assay and 3.8 days (2.1-5.5 days) for the trak-C assay. Among the 42 NAT yield specimens, the HCVcAg assay detected 31 (74%) as core antigen-positive while the trak-C assay detected 37 (88%) as core antigen-positive. Viral loads for the five specimens not detected by the trak-C HCVcAg assay ranged from 100 to 7770 copies/ml. All 54 NAT false-positive specimens were non-reactive on both HCV core antigen assays. CONCLUSION: These data indicate that the trak-C assay has sensitivity approaching routine mini-pool NAT screening for the detection of seronegative HCV infection. In the absence of routine NAT screening for early HCV infection, the use of an HCV core antigen assay should be considered.

Detection of West Nile virus RNA and antibody in frozen plasma components from a voluntary market withdrawal during the 2002 peak epidemic.

BACKGROUND: The US West Nile virus (WNV) epidemic in the summer and fall of 2002 included the first documented cases of transfusion-transmitted WNV infection. In December 2002, the FDA supported a voluntary market withdrawal by the blood banking community of frozen blood components collected in WNV high-activity areas. At the time, the prevalence of viremia and serologic markers for WNV in the blood supply was undefined. STUDY DESIGN AND METHODS: In collaboration with America's Blood Centers, 1468 frozen plasma components (of approx. 60,000 frozen units voluntarily withdrawn from the market) were selectively retrieved from the peak epidemic regions and season (June 23, 2002-September 28, 2002). These units were unlinked, subaliquoted, and tested by WNV enzyme immunoassays (EIAs; Focus Technologies and Abbott Laboratories) and nucleic acid amplification tests (NATs; Gen-Probe Inc. and Roche Molecular Systems). RESULTS: Of the 1468 EIA results from Abbott and Focus, 7 were anti-immunoglobulin M (IgM)- and anti-immunoglobulin G (IgG)-reactive by both assays, 8 and 1 were IgM-only-reactive, and 8 and 23 were IgG-only-reactive, respectively. NAT by Gen-Probe and Roche Molecular Systems yielded one RNA-positive, antibody-negative unit containing approximately 440 RNA copies per mL. An additional 10-fold replicate NAT testing by Gen-Probe on 14 of 15 IgM-reactive specimens yielded 2 additional IgM- and IgG-reactive units with low-level viremia (i.e., 7/10 and 2/10 replicates tested reactive). CONCLUSION: The prevalence of acute (RNA-positive) and recent (IgM-seroreactive) WNV infections indicates that transfusion risk in high-risk areas could have been considerable and that voluntary market withdrawal of frozen components likely averted some WNV transfusion transmissions. The existence of very-low-level viremic units raises concerns, because WNV minipool NAT screening will miss such units and individual NAT may not completely correct this situation.

Analytical and clinical sensitivity of West Nile virus RNA screening and supplemental assays available in 2003.

BACKGROUND: Transfusion-transmitted West Nile virus (WNV) infections were first reported in 2002, which led to rapid development of investigational nucleic acid amplification tests (NAT). A study was conducted to evaluate sensitivities of WNV screening and supplemental NAT assays first employed in 2003. STUDY DESIGN AND METHODS: Twenty-five member-coded panels were distributed to NAT assay manufacturers. Panels included five pedigreed WNV standards (1, 3, 10, 30, and 100 copies/mL), 15 or 16 donor units with very-low-level viremia identified through 2003 screening, and four or five negative control samples. Samples were tested neat in 10 replicates by all assays; for NAT screening assays, 10 replicates were also performed on dilutions consistent with minipool (MP)-NAT. The viral load distribution for 142 MP-NAT yield donations was characterized, relative to the analytical sensitivity of MP-NAT systems. RESULTS: Analytical sensitivities (50% limits of detection [LoD] based on Poisson model of detection of WNV standards) for screening NAT assays ranged from 3.4 to 29 copies per mL; when diluted consistent with MP pool sizes, the 50 percent LoD of screening NAT assays was reduced to 43 to 309 copies per mL. Analytical sensitivity of supplemental assays ranged from 1.5 to 7.7 copies per mL (50% LoD). Detection of RNA in donor units varied consistent with analytical LoD of assays. Detection of low-level viremia after MP dilutions was particularly compromised for seropositive units, probably reflecting lower viral loads in the postseroconversion phase. Based on the viral load distribution of MP-NAT yield donations (median, 3519 copies/mL; range, < 50-690,000), 13 to 24 percent of units had viral loads below the 50 percent LoD of screening NAT assays run in MP-NAT format. CONCLUSION: WNV screening and supplemental assays had generally excellent analytical sensitivity, comparable to human immunodeficiency virus-1 and hepatitis C virus NAT assays. The presence of low-level viremic units during epidemic periods and the impact of MP dilutions on sensitivity, however, suggest the need for further improvements in sensitivity as well as a role for targeted individual-donation NAT in epidemic regions.

Intercomparison of sampling and measurement of 7Be in air at four high-altitude locations in Europe.

For several years 7Be measurements have been conducted at high-altitude stations in Austria (Sonnblick, 3106 m), Switzerland (Jungfraujoch, 3580 m), Germany (Zugspitze, 2962 m), and Italy (Mt. Cimone, 2165 m) with the aim to support a study on vertical ozone transport in the Alps (VOTALP project). Aerosol samples, collected on filtering media with high volume samplers, are analysed for 7Be by high-resolution gamma-spectrometry. Prior to evaluation of the 7Be time series of the four stations, both sampling and measurement procedures were checked for comparability. The results of an intercomparison exercise performed within the mentioned project are reported.

Hepatitis C virus replication kinetics in chimpanzees with self-limited and chronic infections.

The availability of molecular beacon-based, real time polymerase chain reaction (PCR) and a semi-automated sample extraction procedure have made it possible for us to retrospectively examine HCV replication kinetics in HCV naive chimpanzees infected during the past 20 years. We compared these in 17 animals that developed chronic infection, and in 21 that developed self-limited infection. No differences were found in infecting dose, or replication kinetics in the acute phase between these two types of infection. An unanticipated finding was the fact that 10 of 17 animals developing chronic infection partially controlled virus replication for 48 +/- 48 weeks after typical acute phase viraemia, and prior to development of chronic infection. Twenty-nine out of 30 (29/30) sera, which were negative by quantitative PCR during the downregulated period, were, however, positive by the more sensitive Genprobe isothermal transcription-mediated amplification (TMA) assay. Thus, downregulation was not complete. Ten animals showing self-limited infection showed complete resolution of viraemia by TMA assay. Quasispecies analysis revealed that in all, except one case, the virus reappearing after downregulation was essentially identical to that of the originally infecting virus.

First report of human immunodeficiency virus transmission via an RNA-screened blood donation.

BACKGROUND AND OBJECTIVES: Blood banks in the USA have recently introduced minipool nucleic acid amplification testing (MP-NAT) of blood products to reduce the transmission of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) by transfusions. However, MP-NAT is limited in its ability to detect preseroconversion samples with very low viral RNA loads. MATERIALS AND METHODS: To determine whether a red blood cell unit, from an MP-NAT-negative donation, transmitted HIV when transfused to a patient, we compared the viral sequences from the blood donor and recipient. The implicated donation was also tested by commercially available NAT assays at a range of dilution factors to determine whether the infectious unit could have been detected using individual-donation NAT (ID-NAT). RESULTS: Phylogenetic linkage of HIV sequences in the blood donor and recipient confirmed the transmission of HIV by blood transfusion, the first such case identified since introduction of MP-NAT screening in 1999. Viral RNA was reliably detected by ID-NAT, but only inconsistently detected by MP-NAT. CONCLUSIONS: Even following the introduction of MP-NAT, a preseroconversion donation with a viral load of

Chemical characterization of bohrium (element 107)

The arrangement of the chemical elements in the periodic table highlights resemblances in chemical properties, which reflect the elements' electronic structure. For the heaviest elements, however, deviations in the periodicity of chemical properties are expected: electrons in orbitals with a high probability density near the nucleus are accelerated by the large nuclear charges to relativistic velocities, which increase their binding energies and cause orbital contraction. This leads to more efficient screening of the nuclear charge and corresponding destabilization of the outer d and f orbitals: it is these changes that can give rise to unexpected chemical properties. The synthesis of increasingly heavy elements, now including that of elements 114, 116 and 118, allows the investigation of this effect, provided sufficiently long-lived isotopes for chemical characterization are available. In the case of elements 104 and 105, for example, relativistic effects interrupt characteristic trends in the chemical properties of the elements constituting the corresponding columns of the periodic table, whereas element 106 behaves in accordance with the expected periodicity. Here we report the chemical separation and characterization of six atoms of element 107 (bohrium, Bh), in the form of its oxychloride. We find that this compound is less volatile than the oxychlorides of the lighter elements of group VII, thus confirming relativistic calculations that predict the behaviour of bohrium, like that of element 106, to coincide with that expected on the basis of its position in the periodic table.

Performance of second- and third-generation RIBAs for confirmation of third-generation HCV EIA-reactive blood donations. Retrovirus Epidemiology Donor Study.

BACKGROUND: Licensure of an enhanced HCV screening assay (HCV 3.0 EIA) without concurrent licensure of a complementary supplemental assay (i.e., RIBA HCV 3.0 strip immunoblot assay [RIBA-3]) decoupled screening and supplemental testing. In March 1998, the FDA Center for Biologics Evaluation and Research (CBER) recommended the use of RIBA-3 on RIBA HCV 2.0 strip immunoblot assay (RIBA-2)-indeterminate units screened with HCV EIA 3.0. STUDY DESIGN AND METHODS: The sensitivity of RIBA-2 and RIBA-3 was compared in tests on HCV 3.0 EIA-repeatably reactive (RR) units identified immediately after the implementation of HCV 3.0 EIA screening. Two protocols were evaluated: parallel testing of HCV 3.0 EIA-RR units by RIBA-2 and RIBA-3 and reflex testing of HCV 3.0 EIA-RR and RIBA-3-confirmed-positive units by RIBA-2. All specimens with discordant RIBA-2 and RIBA-3 results and a representative sampling with concordant RIBA results were tested by PCR. RESULTS: In the parallel testing protocol, 99,777 donations were screened, with 245 HCV 3.0 EIA-RR specimens included in the study. Of 166 RIBA-2-positive samples, 165 tested positive in RIBA-3 (1 sample reacted to the control superoxide dismutase antigen in RIBA-3). Thirty-two (74%) of 43 RIBA-2-indeterminate specimens and 4 (11%) of 36 RIBA-2-negative specimens tested positive in RIBA-3. HCV RNA was identified in 5 (16%) of 32 RIBA-2-indeterminate/RIBA-3-positive donations, as well as in 26 (70%) of 37 concordant RIBA-2/RIBA-3-positive donations. In the reflex testing protocol, 292,459 donations were screened, with 709 HCV 3.0 EIA-RR specimens included in the study. RIBA-3 testing yielded 517 (73%) positive specimens, of which 50 (9.7%) tested indeterminate and 15 (2.9%) tested negative in RIBA-2. Among the RIBA-discordant specimens, 10 (20%) RIBA-2-indeterminate specimens and 1 (7%) RIBA-2-negative specimens tested positive in PCR; in comparison, 60 (77%) of 78 concordant RIBA-2/RIBA-3-positive units tested positive in PCR. CONCLUSIONS: RIBA-3 is significantly more sensitive than RIBA-2 in testing of HCV 3.0 EIA-screened donations. During the review process of this manuscript, the FDA licensed the RIBA-3 test.

Lookback on donors who are repeatedly reactive on first-generation hepatitis C virus assays:justification and rational implementation.

BACKGROUND: The purpose of this study was to explore strategies to minimize the number of unwarranted consignee notifications resulting from hepatitis C virus (HCV) first-generation (single-antigen) enzyme immunoassay (EIA 1.0) targeted lookback. STUDY DESIGN AND METHOD: The four blood centers participating in this study contributed data on 3753 HCV EIA 1.0-repeatably reactive (RR) donations. The analysis focused on 1) statistical evaluation of HCV EIA 1.0 signal-to-cutoff (S/CO) ratios versus HCV second-generation recombinant immunoblot assay (RIBA 2.0) interpretation from all participating blood centers and 2) RNA testing using transcription-mediated amplification on all HCV EIA 1.0 RR/RIBA 2. 0-positive or -indeterminate specimens and a subset of RIBA 2. 0-negative donations for which specimens were available. RESULTS: Analysis of HCV EIA 1.0 S/CO ratios versus RIBA 2.0 indicated that 1180 (89%) of 1326 RIBA 2.0-positive specimens had an S/CO ratio >2. 5, while 146 (11%) had a ratio 2.5, while 1954 (87%) had a ratio 2.5. HCV RNA was detected in only 2 (1.5%) of 137 HCV EIA 1.0-RR/RIBA 2.0-negative specimens: 1 of these 2 specimens had an S/CO >2.5, while the other had an S/CO 2.5 yielded an 89- percent sensitivity for RIBA 2.0-positive specimens, and donations with an S/CO ratio >2.5 had a 75-percent probability of being RIBA 2.0 positive. A policy recommendation to use the S/CO ratio to triage lookback would prevent unwarranted notification of 87 percent of recipients of blood from RIBA 2.0-negative donors and would result in a failure to notify only 5 to 10 percent of recipients potentially exposed to infectious units.

Lead isotope measurements on aerosol samples with ICP-MS.

Size fractionated aerosols were collected with low pressure Berner impactors on a radio/TV tower 110 m above ground on a hill 10 km east of Bern at a total elevation of 1060 m asl. Two different wind sectors were chosen with the goal of assessing any differences in lead concentration and the 3 radiogenic lead isotopes (206,207,208) for east and west wind, respectively. A leaching technique was used to extract the lead quantitatively from the surface of the impaction foils. This method has been proven to be better suited for airborne particles than complete microwave digestion because it is less time consuming and contamination risk is smaller. Blank considerations played a major role in choosing all the chemicals, tubes, beakers and selecting the analytical method. Lead concentrations were determined with GF-AAS and lead isotopes with two different ICP-MS systems, one being a multicollector system. Precision of the simultaneous multicollector system was found to be at least a factor of 3 better than that of the sequentially operating ICP-MS. The small variations in isotope ratios from the two wind sectors can be distinctly seen with this enhanced precision. The observed relative difference in isotope ratios between east- and westwind was approximately 0.6% for 207Pb/206Pb and approximately 0.5% for 208Pb/206Pb.

Exposure of Allan Hills 84001 and other achondrites on the Antarctic ice.

The enrichment of F on Antarctic meteorites is the result of their exposure to the atmosphere, and its measurement allows a subdivision of the terrestrial age into a duration of exposure on the ice and the time a meteorite was enclosed by the ice. In many cases, the periods of surface exposure are only small fractions of the terrestrial ages of meteorites collected in Antarctica. The enrichment of F on the surfaces of Antarctic achondrites was investigated by means of nuclear reaction analysis (NRA): scanning proton beams with an energy of 2.7 and 3.4 MeV were used to induce the reactions 19F(p, alpha gamma)16O and 19F(p,p gamma)19F, respectively. Gamma signals proportional to the F content were measured. The following Antarctic achondrites were investigated: Martian meteorite ALH 84001; diogenite ALHA77256; the eucrites ALHA81011 and ALHA78132; and in addition, the H5 chondrite ALHA79025. For ALH 84001, our data indicate a period of exposure on the ice of <500 years. Thus, this specimen was enclosed in the ice >95% of its terrestrial age of 13 000 years.