bluuebunny/crossref_metadata_2025 huggingface dataset:
The prevalence of Shiga toxin-producing Escherichia coli in domestic animals and food in Serbia
Authors: ČOBELJIĆ M. , DIMIĆ B. , OPAČIĆ D. , LEPšANOVIĆ Z. , STOJANOVIĆ V. , LAZIĆ S.
Published: March 2005

Faecal samples of 2660 domestic animals from 116 farms and 956 samples of food were examined for the presence of Shiga toxin-producing Escherichia coli (STEC). STEC was recovered from 126 (15·3%) cattle, 135 (11·3%) pigs, 135 (66·8%) sheep, 31 (73·8%) goats, 4 (1%) chicken, and 15 (1·6%) food samples. Of all STEC isolates, 21·5, 25·8 and 15% produced enterohaemolysin, α-haemolysin, and aerobactin respectively, 1·6% displayed localized adherence (LA) to HEp-2 cells, 27·6% were sorbitol negative, and 30% were resistant to antibiotics. Only 14 (3·1%) of the STEC isolates belonged to human infection-associated serogroups (O26, O55, O111, O128 and O157), designated as enterohaemorrhagic E. coli (EHEC). This study revealed that STEC are prevalent in domestic animals, and to a lesser extent in food of animal origin in Serbia, but the absence of a EHEC phenotypic profile (characteristic serogroup, LA, enterohaemolysin production) in most animal STEC strains may explain the low incidence of human STEC infection in this part of the world.
Human coronavirus OC43 causes influenza-like illness in residents and staff of aged-care facilities in Melbourne, Australia
Authors: BIRCH C. J. , CLOTHIER H. J. , SECCULL A. , TRAN T. , CATTON M. C. , LAMBERT S. B. , DRUCE J. D.
Published: March 2005

Three outbreaks of respiratory illness associated with human coronavirus HCoV-OC43 infection occurred in geographically unrelated aged-care facilities in Melbourne, Australia during August and September 2002. On clinical and epidemiological grounds the outbreaks were first thought to be caused by influenza virus. HCoV-OC43 was detected by RT–PCR in 16 out of 27 (59%) specimens and was the only virus detected at the time of sampling. Common clinical manifestations were cough (74%), rhinorrhoea (59%) and sore throat (53%). Attack rates and symptoms were similar in residents and staff across the facilities. HCoV-OC43 was also detected in surveillance and diagnostic respiratory samples in the same months. These outbreaks establish this virus as a cause of morbidity in aged-care facilities and add to increasing evidence of the significance of coronavirus infections.
Prevalence of verotoxin-producing Escherichia coli (VTEC) O157 in Swedish dairy herds
Authors: ERIKSSON E. , ASPAN A. , GUNNARSSON A. , VÅGSHOLM I.
Published: March 2005

A prevalence study of verotoxin-producing Escherichia coli O157 (VTEC O157) was performed in 371 randomly selected dairy herds distributed throughout Sweden. Faecal and manure samples were collected and analysed by immunomagnetic separation and culturing. Data were recorded for each herd regarding herd size, age of sampled animals and whether, in addition to cattle, the farm kept other animals. VTEC O157 was isolated from 33 (8·9%) of the 371 investigated herds. The prevalence was higher (23·3%) in Halland county than in the rest of Sweden (P>0·01). Halland was also the county in Sweden that during the study period had the highest incidence of human VTEC O157 cases. VTEC O157 was not detected on any farm in northern Sweden. Identified risk factors, in the multivariate analyses, for herds being VTEC O157 positive were herd size, geographical localization, presence of pigs on the farm and median age of sampled animals.
An outbreak of Q fever in a prison in Italy
Authors: STARNINI G. , CACCAMO F. , FARCHI F. , BABUDIERI S. , BRUNETTI B. , REZZA G.
Published: March 2005

We observed an outbreak of Q fever in a prison population. Overall, 65 of the 600 prison inmates developed the disease. The location of the prison cells had no apparent effect on the risk of infection. The outbreak was probably due to exposure to dust contaminated by a passing flock of sheep, which at the time of the outbreak was engaged in lambing. These findings highlight the possible emergence of Q fever in settings and populations not normally thought of as being at risk of exposure to the infection.
High-level aminoglycoside resistant enterococci isolated from swine
Authors: JACKSON C. R. , FEDORKA-CRAY P. J. , BARRETT J. B. , LADELY S. R.
Published: March 2005

Approximately 42% (187/444) of swine enterococci collected between the years 1999 and 2000 exhibited high-level resistance to gentamicin (MIC [ges ]500 μg/ml), kanamycin (MIC [ges ]500 μg/ml), or streptomycin (MIC [ges ]1000 μg/ml). Eight aminoglycoside resistance genes were detected using PCR, most frequently ant(6)-Ia and aac(6′)-Ii from Enterococcus faecium. Twenty-four per cent (45/187) of total high-level aminoglycoside-resistant isolates and 26% (4/15) of isolates resistant to high levels of all three antimicrobials were negative for all genes tested. These data suggest that enterococci isolated from swine contain diverse and possibly unidentified aminoglycoside resistance genes.
A boarding school outbreak of pertussis in adolescents: value of laboratory diagnostic methods
Authors: HORBY P. , MACINTYRE C. R. , McINTYRE P. B. , GILBERT G. L. , STAFF M. , HANLON M. , HERON L. G. , CAGNEY M. , BENNETT C.
Published: March 2005

Culture for Bordetella pertussis (B. pertussis) is the traditional gold standard for laboratory diagnosis of pertussis but is insensitive, especially later in the course of illness and in vaccinated persons. Interpretation of serology is limited by the lack of an appropriate reference standard. An outbreak of pertussis in a crowded boarding-school dormitory allowed evaluation of laboratory correlates of infection. Questionnaires, serum samples and throat swabs were collected from members of the exposed group. Serum samples from unexposed controls of a similar age group were used for comparison. B. pertussis PCR was performed on throat swabs, and sera were tested for IgA antibodies against whole-cell (WC) B. pertussis antigen and IgG antibodies to pertussis toxin (PT). The Centers for Disease Control and Prevention definition for pertussis was used to define clinical cases. We evaluated the use of a previously published cut-off for PT IgG of 125 EIA units (EU)/ml. Completed questionnaires were obtained from 115 students, of whom 85 (74%) reported coughing symptoms, including 32 (28%) who met the clinical case definition for pertussis. B. pertussis was detected by PCR in 17 (15%) and WC IgA in 22 (19%) students; neither correlated with symptoms, but dormitory of residence strongly predicted PCR status. The mean PT IgG geometric mean concentration, in this situation of high pertussis exposure, correlated with severity of symptoms and was significantly higher in both symptomatic and asymptomatic children exposed during the outbreak (P<0·001) than in control children. A cut-off for PT IgG of 125 EU/ml was too high in an outbreak situation to be sensitive enough to identify pertussis cases. A case of pertussis in a crowded boarding-school dormitory resulted rapidly in an outbreak. Serology and PCR were useful in identifying the outbreak and commencing disease control measures. The use of serology has mostly been evaluated in community serosurveys, where it is not possible to determine if immunity reflects vaccination, asymptomatic disease or symptomatic disease. This outbreak gave us the opportunity to evaluate the value of serology and PCR in the presence of confirmed exposure to pertussis.
Epidemiology of meningococcal disease in Denmark 1974–1999: contribution of the laboratory surveillance system
Authors: LIND I. , BERTHELSEN L.
Published: March 2005

The Danish meningococcal disease laboratory surveillance system was established in 1974, based on close collaboration between local Departments of Clinical Microbiology and the Reference Laboratory at Statens Serum Institut. The completeness of the clinical notification system integrated with the laboratory surveillance system has been estimated to be more than 95%. Overall 4257 (79%) of 5356 cases of meningococcal disease notified during 1974–1999 were confirmed by culture of Neisseria meningitidis. The proportion of culture-confirmed cases ranged from 70% in 1989 to 89% in 1980. Only 26 patients (0·6%) with culture-confirmed meningococcal disease were not notified. Serological phenotype and susceptibility to penicillin and sulphonamide were determined for all isolates. Multilocus enzyme electrophoresis and/or DNA-based analyses were used for the assessment of clusters and outbreaks. Meningococcal antibody tests and counter-immunoelectrophoresis were used for the ascertainment of suspected cases. These combined systems allowed timely and reliable management of outbreaks and identification of clusters.
The meningococcal antibody test: how useful in the diagnosis of meningococcal disease?
Authors: WEIS N. , BERTHELSEN L. , WACHMANN H. , LIND I.
Published: March 2005

Based on 92537 blood samples received from 7365 patients with a request for a meningococcal antibody test (MAT) during a 10-year period (1986–1995), the usefulness of the test in the diagnosis of meningococcal disease was assessed. Of 635 patients with culture-confirmed meningococcal disease, 88% were seronegative on admittance to hospital and 90% were seropositive 10–15 days after onset of disease. The humoral immune response in children <2 years of age was weaker than in older children and adults. Among 893 MAT-positive patients without culture-confirmed meningococcal disease, 261 (29%) had been notified as cases of meningococcal disease. Among 228 patients notified as serologically confirmed the MAT results were consistent with the clinical diagnosis in 86%. MAT is a reliable tool for establishing a diagnosis in patients with suspected meningococcal disease. Key factors facilitating appropriate interpretation of negative as well as positive test results were: time(s) of sampling(s) after onset of disease, age of the patient and clinical features.
An outbreak of viral meningitis associated with a public swimming pond
Authors: HAURI A. M. , SCHIMMELPFENNIG M. , WALTER-DOMES M. , LETZ A. , DIEDRICH S. , LOPEZ-PILA J. , SCHREIER E.
Published: March 2005

From July to October 2001, 215 cases of aseptic meningitis occurred among the inhabitants of the German city of Kassel and neighbouring counties. A matched case-control study identified bathing in a public, nature-like pond during the beginning of the outbreak as a risk factor for disease [matched odds ratio (mOR) 44·8, 95% confidence interval (CI) 3·9–515·6]. Among bathers, patients with meningitis spent more time in the water (mOR 18·8, 95% CI 2·0–174·1) and swallowed water more frequently (mOR=7·3, 95% CI 0·7–81·8). Of 30 cerebrospinal fluid samples tested, echovirus 30 was cultured from 16, and echovirus 13 from seven. An echovirus 30 sequence obtained from one pond water sample showed a 99% nucleotide and 100% amino-acid homology with patient isolates. This outbreak demonstrates the potential of nature-like swimming ponds to cause widespread community infection with substantial public health impact.
An outbreak of multidrug-resistant Salmonella enterica serotype Newport infections linked to the consumption of imported horse meat in France
Authors: ESPIÉ E. , De VALK H. , VAILLANT V. , QUELQUEJEU N. , Le QUERREC F. , WEILL F. X.
Published: March 2005

In 2003, 14 cases of multidrug-resistant Salmonella Newport infections were reported. This is the first documented foodborne outbreak of multidrug-resistant S. Newport in France. The blaCMY gene was present in all isolates. All cases reported having eaten horse meat from a common wholesaler. The country of origin of the imported meat could not be identified.
The transmission dynamics of groups A and B human respiratory syncytial virus (hRSV) in England & Wales and Finland: seasonality and cross-protection
Authors: WHITE L. J. , WARIS M. , CANE P. A. , NOKES D. J. , MEDLEY G. F.
Published: March 2005

Human respiratory syncytial virus (hRSV) transmission dynamics are inherently cyclical, and the observed genetic diversity (between groups A and B) also appears to have a repeating pattern. A key unknown is the extent to which genetic variants interact immunologically, and thus impact on epidemiology. We developed a novel mathematical model for hRSV transmission including seasonal forcing of incidence and temporary intra- and inter-group partial immunity. Simultaneous model fits to data from two locations (England & Wales, UK, and Turku, Finland) successfully reproduced the contrasting infection dynamics and group A/B dominance patterns. Parameter estimates are consistent with direct estimates. Differences in the magnitude and seasonal variation in contact rate between the two populations alone could account for the variation in dynamics between these populations. The A/B group dominance patterns are explained by reductions in susceptibility to and infectiousness of secondary homologous and heterologous infections. The consequences of the observed dynamic complexity are discussed.
Reappearance of influenza B/Victoria/2/87-lineage viruses: epidemic activity, genetic diversity and vaccination efficacy in the Finnish Defence Forces
Authors: IKONEN N. , PYHÄLÄ R. , AXELIN T. , KLEEMOLA M. , KORPELA H.
Published: March 2005

A new B/Shangdong/7/97-like influenza virus (Victoria/2/87 lineage) predominated during the 2002/2003 epidemic season in Finland and was estimated to account for 2246 of the 13496 feverish upper respiratory tract infections (URIs) occurring among conscripts in the Finnish army. The incidence (1716/10000 conscripts) was indicative of moderate epidemic activity at most. Analysis of the cross-reactive antibodies induced in 1988 suggests that the basis of the protection was probably established during the childhood of the conscripts. Vaccination in autumn 2002 prevented 42% of the URIs during the influenza B outbreak and 71% (95% CI 42–85) of infections interpreted as influenza B. Despite the low genetic variability of the Shangdong/7/97-like viruses, breakages of a potential glycosylation site in haemagglutinin (HA1, position 197) were frequent; their biological significance is discussed. The Shangdong/7/97-like strains were HA1/NA reassortants, as were also the less abundant strains that for HA1 belonged to the B/Yamagata/16/88 lineage. A further reassortment, which probably emerged during the outbreak in one of the garrisons, supports our hypothesis that circumstances in these settings may especially favour the emergence of diversity by reassortment.
Seroprevalence of parvovirus B19 infection in daycare educators
Authors: GILBERT N. L. , GYORKOS T. W. , BÉLIVEAU C. , RAHME E. , MUECKE C. , SOTO J. C.
Published: March 2005

This study was undertaken to provide first-time estimates for the seroprevalence of parvovirus B19 infection among daycare educators in Montréal, Canada, and to identify factors associated with seropositivity. A cross-sectional design was used. Directors and educators from 81 daycare centres (DCCs) were surveyed about DCC and personal characteristics respectively, and serum samples from 477 female educators were tested for parvovirus B19 IgG antibodies. The seroprevalence of parvovirus B19 was 70%. Parvovirus B19 seropositivity was significantly associated with age and with working experience in DCCs, but the latter association was restricted to educators aged less than 40 years. In conclusion, working as a daycare educator appears to be associated with increased risk of acquiring parvovirus B19 infection, but this finding will require further investigation. Because of the large proportion of educators susceptible to acquiring parvovirus B19 infection, our findings also highlight the need for preventive measures.
Management of chronic hepatitis C in French departments of internal medicine and infectious diseases
Authors: CACOUB P. , GODEREL I. , MORLAT P. , SENE D. , MYERS R. P. , ALRIC L. , LOUSTAUD-RATTI V. , MELIN P. , LIMAL N. , OUZAN D. , PERRONNE C. , CARRAT F.
Published: March 2005

This prospective, multicentre study was conducted during 2–30 April 2001 in the internal medicine/infectious diseases services in France and included data from 1858 hepatitis C virus (HCV)-infected patients, half of whom were HIV co-infected. The aims were to outline the type of pre-therapeutic evaluation of HCV infection performed (HCV RNA, genotype, liver biopsy); determine the proportion and characteristics of patients receiving antiviral treatment; and determine if any changes in these parameters had occurred between 1995 and 2001. Patients whom had a complete pre-therapeutic evaluation (39%, 709/1834) and received antiviral treatment (38%, 690/1830) were more likely to have abnormal liver biochemistry, cirrhosis and cryoglobulinaemia (P<0·001). Injecting drug users and HIV-co-infected patients were less likely to have a complete pre-therapeutic evaluation or receive antiviral treatment (P<0·001). A complete pre-therapeutic evaluation was more often performed in 2001 than in 1995 (39% vs. 6%, P<0·001), including qualitative HCV RNA testing (91% vs. 68%, P<0·001), genotyping (59% vs. 7%, P<0·001) and a liver biopsy (60% vs. 29%, P<0·001). The frequency of anti-HCV treatment approximately doubled between 1995 and 2001 (20% vs. 38%, P<0·001). Although adherence to consensus recommendations regarding pre-therapeutic evaluation is not ideal, a substantial improvement has occurred since 1995. Nevertheless, means of increasing the availability of antiviral therapies, particularly for patients with HIV co-infection or injecting drug use, require further study.
Modelling and determination of the transmission contact rate for contagious bovine pleuropneumonia
Authors: BALENGHIEN T. , CHALVET-MONFRAY K. , BICOUT D. J. , SABATIER P.
Published: March 2005

Contagious bovine pleuropneumonia (CBPP) is a cattle respiratory disease that represents one of the major threats to cattle health and production in sub-Saharan Africa. The transmission contact rate of CBPP plays a key role in the spreading dynamics of the disease. We have developed an approach based on the combination of a SEIR model describing the spread of CBPP with the dynamic of seroconversion to determine the transmission contact rate for CBPP. This method has been subsequently applied to serological diagnostic data obtained from an experimental vaccine trial. As a result, we find that the transmission contact rates for subclinical, clinical and chronic infective states are respectively, 0·084/N, 0·45 and 0·14/N per animal per day, where N is the herd population size, and the basic reproductive number corresponding to this trial (N=28) is R0=27.
Severe illness and death among injecting drug users in Scotland: a case-control study
Authors: TAYLOR A. , HUTCHINSON S. , LINGAPPA J. , WADD S. , AHMED S. , GRUER L. , TAYLOR T. H. , ROY K. , GILCHRIST G. , McGUIGAN C. , PENRICE G. , GOLDBERG D.
Published: March 2005

Between April and September 2000, 60 injecting drug users in Scotland died or were hospitalized with severe illness. Laboratory investigations suggested that Clostridium novyi and other bacteria were important aetiological agents. To determine associated environmental/behavioural factors a case-control study was undertaken with 19 ‘definite’ and 32 ‘probable’ cases in Glasgow, Scotland. For every deceased case (n=19), up to three proxy individuals were interviewed. Three controls were identified for each case. Multivariate logistic regression analyses compared (i) all cases and controls; (ii) definite cases and matched controls; (iii) probable cases and matched controls. In all three analyses injecting into muscle or skin and injecting most of the time with a filter used by someone else were the variables most strongly associated with illness. Comparing only muscle-injecting cases and controls, cases were significantly more likely to have injected larger amounts of heroin per average injection than were controls. The findings make an important epidemiological contribution to the understanding of the public health and clinical implications of the contamination of illicit drugs by histotoxic clostridia.
Miocene climate change recorded in the chemical and isotopic (Pb, Nd, Hf) signature of Southern Ocean sediments
Authors: Vlastélic Ivan , Carpentier Marion , Lewin Éric
Published: March 2005

The Middle Miocene transition from carbonate to biosilica sedimentation at DSDP site 266 (Australian‐Antarctic basin) reflects a global transition toward a colder climate. The 143Nd/144Nd, 176Hf/177Hf, and Al/Ti of bulk sediments display systematic, coupled variations through time, which have been attributed to a change of the detrital source. This change could correspond to a reduction of input from the Antarctic continent, an increase of input from the Kerguelen volcanic province, or both. Mixing models based on Nd isotopes and Al/Ti suggest a 30–40% reduction of Antarctic input and an equivalent increase of Kerguelen input during the Miocene. Reduction of Antarctic input may result from the formation of a stable East Antarctic ice sheet. Consistently, Pb isotopes and trace element systematics suggest a change of weathering style during the Miocene, with an increase in physical weathering, or a reduction of chemical weathering, after 15 Ma. Increase of Kerguelen input may reflect the initiation, or enhancement, of the Antarctic Circumpolar Current (ACC), thus raising the possibility of a simultaneous onset of North Atlantic Deep Water production and the ACC during the Middle Miocene. In addition, large geochemical oscillations occurred during the Pliocene, possibly reflecting fluctuation in strength of the ACC or, alternatively, periods of instability of the Antarctic ice sheet.
Time‐dependent response of the global ocean clathrate reservoir to climatic and anthropogenic forcing
Authors: Archer David , Buffett Bruce
Published: March 2005

Buffett and Archer (2004) showed a model of the steady state global ocean clathrate reservoir that reproduces drill data and predicts a global methane inventory of about 5000 Gton C. The model inventory is very sensitive to ocean temperature, with factor‐of‐two changes in methane inventory in response to temperature changes of 1.5°C. Here we explore the potential time‐dependent behavior of the clathrate reservoir, assuming simple first‐order rate constants for methane accumulation and meltdown in response to changes in the predicted steady state reservoir. For melting, we divide the reservoir into two parts, one melting catastrophically and the other slowly. Evolution of clathrates through geologic time is very sensitive to the choice of these rate constants. A positive feedback exists during a transient meltdown event, stronger if the catastrophic‐melting fraction is high and its melting timescale is fast. A clathrate reservoir governed by such kinetics would melt down periodically, on a multimillion‐year timescale determined by the rate constant for clathrate accumulation. Ideally, we would like a model that predicts runaway melting in the Paleocene and stability in the Pleistocene. However, the model is most unstable when climate is cold, rather than warm. Opting for stability in the Pleistocene constrains the melting kinetic parameters, leaving one degree of freedom. The grow‐in timescale must be 5 Myr or longer, to get the deglacial δ13C right, but shorter than 10 Myr, in order for clathrates to have built up through geologically recent cooling. The model thus constrained predicts methane fluxes of 200 Gton C or less on deglaciations, but eventual releases of 2000–4000 Gton C in response to a ∼2000 Gton C anthropogenic carbon release. Anthropogenic climate change differs from a deglaciation in that it warms the ocean to temperatures not seen in millions of years.
Bio‐optical feedbacks among phytoplankton, upper ocean physics and sea‐ice in a global model
Authors: Manizza Manfredi , Le Quéré Corinne , Watson Andrew J. , Buitenhuis Erik T.
Published: March 2005

Phytoplankton biomass modifies the penetration of light and impacts the physical properties of the upper ocean. We quantify these impacts and the feedbacks on phytoplankton biomass for the global ocean using an Ocean General Circulation Model coupled to an ocean biogeochemistry model. Phytoplankton biomass amplifies the seasonal cycle of temperature, mixed layer depth and ice cover by roughly 10%. At mid and high latitudes, surface temperature warms by 0.1–1.5°C in spring/summer and cools by 0.1–0.3°C in fall/winter. In the tropics, phytoplankton biomass indirectly cools the ocean surface by 0.3°C due to enhanced upwelling. The mixed layer stratifies by 4–30 m everywhere except at high latitudes. At high latitudes, the sea‐ice cover is reduced by up to 6% in summer and increased by 2% in winter, leading to further feedbacks on vertical mixing and heat fluxes. Physical changes drive a positive feedback increasing phytoplankton biomass by 4–12% and further amplifies the initial physical perturbations.
Preconditions for El Niño and La Niña onsets and their relation to the Indian Ocean
Authors: Kug Jong‐Seong , An Soon‐Il , Jin Fei‐Fei , Kang In‐Sik
Published: March 2005

El Niño/La Niña onset is a challenging problem of ENSO prediction. In this study, we introduce two precursors of El Niño and La Niña onsets. One is the equatorial heat content, and the other is the Western Pacific (WP) wind. When the two precursors are considered together, both the El Niño and La Niña onsets can be highly predictable. In particular, the persistence of the WP wind is more important for the onset than sporadic wind events. The persistent WP westerly (easterly) wind tends to be concurrent with the Indian Ocean SST cooling (warming). The Indian Ocean SST anomaly is partly correlated to an ENSO event during the previous winter. We demonstrate that an asymmetric relation between the Indian Ocean SST and ENSO can result in asymmetric progress of onset in the opposite ENSO phases.
Long duration meteor echoes characterized by Doppler spectrum bifurcation
Authors: Bourdillon A. , Haldoupis C. , Hanuise C. , Le Roux Y. , Menard J.
Published: March 2005

We report on a new category of long lasting meteor echoes observed occasionally with HF and VHF radars. These meteoric returns, which have lifetimes from many seconds to a few minutes, are characterized by a distinct Doppler spectral signature showing a pronounced Doppler bifurcation which includes narrow bands of discrete Doppler velocities, often of opposite polarity. The large signal to noise ratios and the narrowness of the spectra imply that coherent or Bragg scattering is not of relevance here, therefore these echoes do not associate with the long living meteor‐induced backscatter (MIB) from the lower E region. A reasonable interpretation needs to explain both the Doppler spectrum bifurcation and the long echo duration. As such, we propose the idea of a structured vertical wind shear in the lower E region which traps different fragments of a meteor trail plasma in the same way that sporadic E layers form. These trail parts inside the shear‐related wind profile may act as relatively long‐lasting meteoric reflectors moving with different Doppler velocities, also of opposite polarity.
AIRS hyper‐spectral measurements for climate research: Carbon dioxide and nitrous oxide effects
Authors: Aumann H. H. , Gregorich David , Gaiser Steve
Published: March 2005

Mid‐tropospheric temperature soundings over tropical oceans by the Atmospheric Infrared Sounder, AIRS, using 4.3 micron CO2 R‐branch and P‐branch channels independently measure about 260 K with one Kelvin semi‐annual variability. The difference between the soundings, which cancels seasonal variability, has increased over the past two years by 47 ± 9 mK/year. This trend is explained by the increase of 2.2 ± 0.4 ppmv/year and 0.6 ± 0.2 ppbv/year in the abundance of CO2 and N2O, respectively, which results in a 35 mK/year trend. The ability to achieve closure at this level with only two years of AIRS data is very encouraging for measurements of other trends of atmospheric temperatures relevant to climate research. AIRS covers the 3.7 to 15.4 micron region with spectral resolution of λ/Δλ = 1200. AIRS was launched into a polar 705 km altitude orbit on the EOS Aqua spacecraft on May 4, 2002, and has an expected on‐orbit lifetime of seven years.
Theory of dispersive shear Alfvén wave focusing in Earth's magnetosphere
Authors: Rankin R. , Marchand R. , Lu J. Y. , Kabin K. , Tikhonchuk V. T.
Published: March 2005

It is shown that perpendicular gradients in shear Alfvén wave (SAW) dispersion regulate the localization of wave power on nightside geomagnetic L‐shells where narrow Field Line Resonances (FLRs) form. We estimate the timescale for this process, ω0tc = 1/, and demonstrate that it is analogous to optical wave focusing. Here, β is the gradient in the global wave dispersion parameter across L‐shells in the equatorial plane, and α is the gradient in the SAW eigenfrequency. It is demonstrated that dispersive SAWs with wave numbers and frequencies in a certain range, are subject to magnetospheric focusing onto L‐shells where they reach large amplitude and are expected to dissipate. Our theory addresses a class of arc scales that are comparable to the electron inertial length near the ionosphere, or the ion gyroradius near the equatorial plane. We further demonstrate that when the gradient in the SAW frequency reverses across the edges of auroral density cavities, it naturally traps dispersive SAWs and focuses them down to the inertial scale.
Deformation of the subducted Indian lithospheric slab in the Burmese arc
Authors: Rao N. Purnachandra , Kalpna
Published: March 2005

Stress inversion of focal mechanism data in the Burmese arc region indicates distinct stress fields above and below 90 km along the subducted Indian lithospheric slab. In the upper part, the σ1 and σ3 axes trend NNE and ESE respectively, in conjunction with the ambient stress field of the Indian plate. However, in the lower part of the slab there is no preferred orientation of the σ1 or σ2 axes, but a very well defined σ3 axis is observed, that trends steeply in the down‐dip direction. It is inferred that while the upper part is governed by the NNE oriented horizontal plate tectonic forces, the lower part is governed entirely by tensile forces due to gravitational loading on the subducted slab. A model of attempted slab detachment at the base of the lithospheric contact zone is suggested, which is supported by results of high‐resolution seismic tomographic studies in this region.
Asymmetric impact of the North and South Pacific on the equator in a coupled climate model
Authors: Yang H. , Jiang H. , Tan B.
Published: March 2005

Relative contributions of the North and South Pacific to the equatorial ocean are estimated in a coupled climate model. Idealized experiments show that the South Pacific contributes 30–50% more than the North Pacific to the equatorial ocean temperature change, because the warming in the North Pacific can induce an additional cold Rossby wave at around 20°N that tends to block the warm effect from the central North Pacific, while the South Pacific influence can be easily convoyed to the equator through the interior pathway.
Water content of ambient aerosol during the Pittsburgh Air Quality Study
Authors: Khlystov Andrey , Stanier Charles O. , Takahama Satoshi , Pandis Spyros N.
Published: March 2005

The aerosol water content and volumetric growth factors of fine particulate matter were measured during July–August 2001 and January–June 2002 in an urban park about 6 km from downtown Pittsburgh, Pennsylvania. Most of the aerosol during the study was transported to the region from other areas, and its composition and concentration were characteristic of the regional particulate matter in the northeastern United States. During the summer months the ambient aerosol practically always contained water even when the relative humidity (RH) was as low as 30%. In contrast, during the winter the aerosol was dry below 60% RH. The spring months were characterized by a transitional behavior between these two states. The observed seasonal behavior can be explained by the aerosol acidity. The summer aerosol was acidic and retained water at low RH. The winter aerosol was neutral and became wet when the relative humidity reached the deliquescence point of ammonium nitrate. The observations during July 2001 were compared with the predictions of the thermodynamic Gibbs Free Energy Minimization (GFEMN) model and the aerosol inorganics model (AIM), neglecting the organic aerosol contribution to water absorption. The models under‐predicted water concentrations by about 35%, but no clear correlation between organic mass and the excess water was observed. On average, the contribution of the organics to water absorption appeared to be higher during the afternoon hours and when the aerosol was presumably more oxidized.
Aerosol optical thickness retrieval over land and water using Global Ozone Monitoring Experiment (GOME) data
Authors: Kusmierczyk‐Michulec J. , de Leeuw G.
Published: March 2005

An algorithm for the retrieval of the aerosol optical thickness over land and over water from Global Ozone Monitoring Experiment (GOME) data is presented. The cloud fraction in the GOME pixels is determined using the Fast Retrieval Scheme for Clouds From the Oxygen A Band (FRESCO) algorithm. Surface contributions to the top of atmosphere reflectance are determined from the GOME surface reflectance database. The aerosol retrieval algorithm uses lookup tables that were created using the radiative transfer model 6S. The algorithm allows retrieving the aerosol types characterized by Ångstrom coefficients in the range from −0.1 to 2.8; i.e., the range of values observed by the AERONET ground‐based measurements. Validation of the algorithm done using the AERONET Sun photometer data for 12 sites in Europe and Africa, for the year 1997, shows very good agreement. The correlation coefficient between the satellite retrieval and AERONET data for the wavelength of 440 nm is 97%, and for 670 nm it is 94%. Validation of the algorithm for the year 2000 was done for a few sites with similar results. The algorithm has been successfully tested over an island influenced by Saharan dust (i.e., Cape Verde, 16°N, 22°W) and over a site located near the Saharan desert (i.e., Bondoukoui, 11°N, 3°W). For other sites located near the Saharan desert such as Bidi Bahn (14°N, 2°W) and Banizombou (13°N, 2°E), the agreement was very good at 440 nm. The algorithm has not been tested over other bright surfaces such as ice‐covered regions. Examples of the spatial distribution of the aerosol optical thickness over Europe, north Africa, and the North Atlantic for the year 1997 and 2000 are presented.
Control of Nuclear Export of hnRNP A1
Authors: Lichtenstein Michal , Guo Wei , Tartakoff Alan M.
Published: March 2005

mRNA export is mediated by RNA‐binding proteins which shuttle between the nucleus and cytoplasm. Using an in vitro unidirectional export assay, we observe that the shuttling mRNA‐binding protein, hnRNP A1, is exported only extremely slowly unless incubations are supplemented with snRNA‐specific oligonucleotides which inhibit splicing. In vivo microinjection experiments support this conclusion. Like many examples of nucleocytoplasmic transport, export of hnRNP A1 requires energy and is sensitive to the presence of wheat germ agglutinin. It does not, however, require supplementation with cytoplasmic proteins. Although the exportin, Crm1, is needed for export of several varieties of RNA, both the in vitro assay and in vivo assays show that it is not required for export of hnRNP A1. In vitro and in vivo studies also show that inhibition of transcription allows continued shuttling of hnRNP A1 and in fact accelerates its export. Judging from the stimulatory effects of targeted destruction of snRNAs, this is likely to reflect completion of the covalent maturation of the RNAs with which hnRNP A1 associates. These observations therefore provide a simple explanation of why multiple RNA‐binding proteins relocate to the cytoplasm upon inhibition of transcription in vivo.
Cerebral Fractional Oxygen Extraction is Inversely Correlated with Oxygen Delivery in the Sick, Newborn, Preterm Infant
Authors: Kissack Christopher M , Garr Rosaline , Wardle Stephen P , Weindling A Michael
Published: March 2005

Cerebral blood flow (CBF) is known to be low in newborn infants, but this has not been shown to be damaging. The purpose of this study was to investigate the relationships between cerebral haemoglobin flow, blood flow, oxygen delivery, oxygen consumption, venous saturation, and fractional oxygen extraction (OEF) in newborn, preterm infants. Measurements were made by near-infrared spectroscopy in 13 very preterm, extremely low birth weight infants (median gestation 25 weeks) during the first 3 days after birth. There was a negative correlation between cerebral oxygen delivery and OEF ( n=13, r=−0.5, P=0.03), which implies that when there is a reduction in cerebral oxygen delivery in sick preterm infants, increased cerebral oxygen extraction may be responsible for maintaining oxygen availability to the brain. During the first 3 days after birth CBF ( n=13, r=0.7, P=0.01), oxygen delivery ( n=13, r=0.5, P=0.03), and oxygen consumption ( n=13, r=0.7, P=0.004) all increased. This increase in oxygen consumption indicates increased cerebral metabolic activity after birth, which is likely to be a normal adaptation to extrauterine life. The increases in blood flow and oxygen delivery may also be normal adaptations that facilitate this increase in metabolic activity. There was a decrease ( P=0.04) in mean (±s.d.) cerebral OEF between day 1 (0.37±0.10) and day 2 (0.29±0.09), with no change between day 2 and day 3. Taking into account the negative correlation between OEF and oxygen delivery, this decrease in OEF may be because of increased oxygen delivery during this time.
Preferred Stereoselective Transport of the D-isomer of cis-4-[18F]fluoro-proline at the Blood–Brain Barrier
Authors: Langen Karl-Josef , Hamacher Kurt , Bauer Dagmar , Bröer Stefan , Pauleit Dirk , Herzog Hans , Floeth Frank , Zilles Karl , Coenen Heinz H
Published: March 2005

Generally, L-amino acids are preferably transported into mammalian cells compared with their D-isomers, and only L-amino acids are incorporated into proteins. Former studies, however, indicated that D-[H]proline is accumulated in the brain of mice after injection, while L-[3H]proline is not. We investigated the differential cerebral uptake of the D- and L-isomers of the PET tracer cis-4-[18F]fluoroproline (D-/L- cis-FPro) and of D-/L-[3H]proline (D-/L-Pro) in rats by dual tracer autoradiography and the uptake of D- cis-FPro in two human subjects by PET. The standardized uptake value (SUV) of D- cis-FPro in the cerebral cortex of rats 2 h p.i. was 3.05±1.18 ( n=9) versus 0.06±0.01 ( n=4) for L- cis-FPro ( P<0.001) and 1.29±0.27 ( n=4) for D-Pro versus 0.30±0.14 ( n=9) for L-Pro ( P<0.001). Analysis of the rat brain tissue after injection of D- cis-FPro ( n=3) revealed no radioactivity in the proteins but a relevant part in the form of L- trans-FPro. The PET studies yielded a four- to five-fold higher SUV and influx rate constant in the human cortex for D- cis-FPro than for L- cis-FPro. We conclude that D- cis-FPro and D-Pro are preferably transported at the blood–brain barrier compared with their L-isomers and isomerized to the L-form within the brain. Thus, D-Pro in the plasma might be a source of intracerebral L-proline, which has been shown to act as a modulator of excitatory neurotransmission.
Hsp70 Overexpression Sequesters AIF and Reduces Neonatal Hypoxic/Ischemic Brain Injury
Authors: Matsumori Yasuhiko , Hong Shwuhuey M , Aoyama Koji , Fan Yang , Kayama Takamasa , Sheldon R Ann , Vexler Zinaida S , Ferriero Donna M , Weinstein Philip R , Liu Jialing
Published: March 2005

Apoptosis is implicated in neonatal hypoxic/ischemic (H/I) brain injury among various forms of cell death. Here we investigate whether overexpression of heat shock protein (Hsp) 70, an antiapoptotic protein, protects the neonatal brain from H/I injury and the pathways involved in the protection. Postnatal day 7 (P7) transgenic mice overexpressing rat Hsp70 (Tg) and their wild-type littermates (Wt) underwent unilateral common carotid artery ligation followed by 30 mins exposure to 8% O2. Significant neuroprotection was observed in Tg versus Wt mice on both P12 and P21, correlating with a high level of constitutive but not inducible Hsp70 in the Tg. More prominent injury was observed in Wt and Tg mice on P21, suggesting its continuous evolution after P12. Western blot analysis showed that translocation of cytochrome c, but not the second mitochondria-derived activator of caspase (Smac)/DIABLO and apoptosis-inducing factor (AIF), from mitochondria into cytosol was significantly reduced in Tg 24 h after H/I compared with Wt mice. Coimmunoprecipitation detected more Hsp70 bound to AIF in Tg than Wt mice 24 h after H/I, inversely correlating with the amount of nuclear, but not cytosolic, AIF translocation. Our results suggest that interaction between Hsp70 and AIF might have reduced downstream events leading to cell death, including the reduction of nuclear AIF translocation in the neonatal brains of Hsp70 Tg mice after H/I.
Cytochrome c, a Biomarker of Apoptosis, is Increased in Cerebrospinal Fluid from Infants with Inflicted Brain Injury from Child Abuse
Authors: Satchell Margaret A , Lai Yichen , Kochanek Patrick M , Wisniewski Stephen R , Fink Ericka L , Siedberg Neal A , Berger Rachel P , DeKosky Steven T , Adelson P David , Clark Robert SB
Published: March 2005

Previous studies suggest that delayed neuronal death occurs in patients with inflicted traumatic brain injury (TBI) from child abuse. It is unknown whether the mode of this delayed neuronal death represents apoptosis or necrosis, a distinction that carries therapeutic ramifications. Cytochrome c, an electron transport chain component, can be released from mitochondria under conditions of cellular stress, whereupon it can initiate and serve as a biomarker of apoptosis. To resolve this issue, cytochrome c concentration was determined in 167 ventricular cerebrospinal fluid (CSF) samples from 67 infants and children with TBI (including 15 patients diagnosed with child abuse) by ELISA. Controls included lumbar CSF from 19 infants and children without trauma or meningitis. A multivariate model adjusted for multiple within-subject observations was used to identify clinical variables associated with CSF cytochrome c. Other apoptosis-related proteins were also examined in a subset of TBI patients. Increased CSF cytochrome c was independently associated with inflicted TBI ( P = 0.0001) and female gender ( P = 0.04), but not age, Glasgow coma scale score, or survival. Other apoptosis-related proteins including Fas and caspase-1 were increased in CSF after TBI, but did not independently discriminate between accidental and inflicted TBI. These data suggest that apoptosis, as detected by the presence of cytochrome c in CSF, is uniquely prominent among the subset of TBI patients diagnosed with child abuse. The degree of apoptosis after TBI also appears to be gender-dependent. Development of strategies targeting apoptosis after TBI, particularly in victims of child abuse and in girls, appears justified.
Spatiotemporal Evolution of Functional Hemodynamic Changes and Their Relationship to Neuronal Activity
Authors: Sheth Sameer A , Nemoto Masahito , Guiou Michael W , Walker Melissa A , Toga Arthur W
Published: March 2005

Brain imaging techniques such as functional magnetic resonance imaging (fMRI) have provided a wealth of information about brain organization, but their ability to investigate fine-scale functional architecture is limited by the spatial specificity of the hemodynamic responses upon which they are based. We investigated the spatiotemporal evolution of hemodynamic responses in rat somatosensory cortex to electrical hindpaw stimulation. We combined the advantages of optical intrinsic signal imaging and spectroscopy to produce high-resolution two-dimensional maps of functional changes in tissue oxygenation and blood volume. Cerebral blood flow changes were measured with laser-Doppler flowmetry, and simultaneously recorded field potentials allowed comparison between hemodynamic changes and underlying neuronal activity. For the first 2 to 3 secs of activation, hemodynamic responses overlapped in a central parenchymal focus. Over the next several seconds, cerebral blood volume changes propagated retrograde into feeding arterioles, and oxygenation changes anterograde into draining veins. By 5 to 6 secs, responses localized primarily in vascular structures distant from the central focus. The peak spatial extent of the hemodynamic response increased linearly with synaptic activity. This spatial spread might be because of lateral subthreshold activation or passive vascular overspill. These results imply early microvascular changes in volume and oxygenation localize to activated neural columns, and that spatial specificity will be optimal within a 2- to 3-sec window after neuronal activation.
Development of a Tracer Kinetic Plasma Input Model for (R)-[11C]PK11195 Brain Studies
Authors: Kropholler Marc A , Boellaard Ronald , Schuitemaker Alie , van Berckel Bart NM , Luurtsema Gert , Windhorst Albert D , Lammertsma Adriaan A
Published: March 2005

(R)-[11C]PK11195 ([1-(2-chlorophenyl)- N-methyl- N-(1-methylpropyl]-3-isoquinoline carboxamide) is a ligand for the peripheral benzodiazepine receptor, which, in the brain, is mainly expressed on activated microglia. Using both clinical studies and Monte Carlo simulations, the aim of this study was to determine which tracer kinetic plasma input model best describes (R)-[11C]PK11195 kinetics. Dynamic positron emission tomography (PET) scans were performed on 13 subjects while radioactivity in arterial blood was monitored online. Discrete blood samples were taken to generate a metabolite corrected plasma input function. One-tissue, two-tissue irreversible, and two-tissue reversible compartment models, with and without fixing K1/ k2 ratio, k4 or blood volume to whole cortex values, were fitted to the data. The effects of fixing parameters to incorrect values were investigated by varying them over a physiologic range and determining accuracy and reproducibility of binding potential and volume of distribution using Monte Carlo simulations. Clinical data showed that a two-tissue reversible compartment model was optimal for analyzing (R)-[11C]PK11195 PET brain studies. Simulations showed that fixing the K1/ k2 ratio of this model provided the optimal trade-off between accuracy and reproducibility. It was concluded that a two-tissue reversible compartment model with K1/ k2 fixed to whole cortex value is optimal for analyzing (R)-[11C]PK11195 PET brain studies.
Effects of Intravenous Dimethyl Sulfoxide on Ischemia Evolution in a Rat Permanent Occlusion Model
Authors: Bardutzky Juergen , Meng Xianjun , Bouley James , Duong Timothy Q , Ratan Rajiv , Fisher Marc
Published: March 2005

Dimethyl sulfoxide (DMSO) has a variety of biological actions that suggest efficacy as a neuroprotectant. We (1) tested the neuroprotective potential of DMSO at different time windows on infarct size using 2,3,5-triphenyltetrazolium staining and (2) investigated the effects of DMSO on ischemia evolution using quantitative diffusion and perfusion imaging in a permanent middle cerebral artery occlusion (MCAO) model in rats. In experiment 1, DMSO treatment (1.5 g/kg intravenously over 3 h) reduced infarct volume 24 h after MCAO by 65% ( P<0.00001) when initiated 20 h before MCAO, by 44% ( P = 0.0006) when initiated 1 h after MCAO, and by 17% ( P = 0.11) when started 2 h after MCAO. Significant infarct reduction was also observed after a 3-day survival in animals treated 1 h after MCAO ( P = 0.005). In experiment 2, treatment was initiated 1 h after MCAO and maps for cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) were acquired before treatment and then every 30 mins up to 4 h. Cerebral blood flow characteristics and CBF-derived lesion volumes did not differ between treated and untreated animals, whereas the ADC-derived lesion volume essentially stopped progressing during DMSO treatment, resulting in a persistent diffusion/perfusion mismatch. This effect was mainly observed in the cortex. Our data suggest that DMSO represents an interesting candidate for acute stroke treatment.