bluuebunny/crossref_metadata_2025_split huggingface dataset:
Divergent evolution of hemagglutinin and neuraminidase genes in recent influenza A:H3N2 viruses isolated in Canada
Authors: Abed Yacine , Hardy Isabelle , Li Yan , Boivin Guy 
Published: September 2002

AbstractLimited information is available concerning the molecular drift of the influenza neuraminidase (NA) genes. We report on the genetic variability of the NA gene from 31 influenza A:H3N2 viruses isolated in the Province of Québec (Canada) during the last three flu seasons (1997–2000). Amino acid substitutions within the NA protein were observed at rates of 1.01% and 0.45% between strains of the 1997–1998 and 1998–1999 seasons and between those of the 1998–1999 and 1999–2000 seasons, respectively. In most strains (28/31), amino acid changes occurred within at least one of four codons (197, 339, 370, and 401) previously implicated as antigenic sites. The 8 functional and 10 framework residues that compose the catalytic site of the NA enzyme were completely conserved over the study period. All isolates contained the seven conserved asparagine‐linked glycosylation sites found in the NA of the progenitor A/Hong Kong/8/68 strain. In addition, most strains (30/31) had an eighth potential glycosylation site at position 329, whereas a ninth one was found at position 93 in 16 strains. The NA of all strains in this study was related to that of the vaccine strain A/Beijing/353/89, whereas the HA genes of these strains were related to the A/Beijing/32/92 vaccine strain. Thus, it appears that recent influenza strains continue to evolve from a reassortant produced during the cocirculation of the two above variants. Interestingly, some strains whose HA genes were closely related showed significant differences in their NA genes and conversely. This study confirms the importance of analyzing both the NA and the HA genes to assess the evolution of recent influenza epidemic strains. J. Med. Virol. 67:589–595, 2002. © 2002 Wiley‐Liss, Inc.
Prevalence of respiratory syncytial virus IgG antibodies in infants living in a rural area of Mozambique
Authors: Roca Anna , Abacassamo Fatima , Loscertales Mari‐Paz , Quintó Llorenç , Gómez‐Olivé Xavier , Fenwick Fiona , Saiz Juan Carlos , Toms Geoffrey , Alonso Pedro L. 
Published: September 2002

AbstractA case control study was carried out in Manhiça (Mozambique). Serum samples were collected from infants < 1 year of age in hospital to assess the effect of serum antibodies on the incidence of respiratory syncytial virus (RSV) infection. Sera were collected from a total of 31 cases of RSV infection and paired uninfected controls matched for age and sex. Anti‐RSV antibodies were assessed by a membrane fluorescent antibody test (MFAT) for immunoglobulin G (IgG) antibodies and by a neutralizing antibody test. IgG RSV antibodies were of higher prevalence and at higher levels in the control group when compared to the infected case group (P < 0.001), indicating an important role for IgG antibodies in protection. To assess infection before recruitment, IgA RSV antibodies were also measured by MFAT. IgA RSV antibody prevalence was very low in patients and controls (0/31 and 4/31 respectively), suggesting that most of the detected IgG RSV antibody in both groups was of maternal origin. Re‐analysis of data from the subset of 27 matched, IgA RSV antibody negative infant pairs mirrored the full analysis indicating that maternal antibody has an important role in RSV protection. Similar results were obtained when neutralizing antibodies were measured and when the measurement was done against subgroup A virus strain A2, subgroup B virus strain 8/60 and a contemporary subgroup A isolate, Moz00. No significant differences in the reactivity of maternal antibodies with the three virus strains were observed. The data described below represent the first analysis of the role of maternal antibodies in reducing the risk of pediatric infection in developing countries. The results reinforce the concept of maternal vaccination for the control of RSV in very young children in whom the risk and severity of infection are the highest. J. Med. Virol. 67:616–623, 2002. © 2002 Wiley‐Liss, Inc.
High genetic diversity revealed by the study of TLMV infection in French hemodialysis patients
Authors: Gallian Pierre , Biagini Philippe , Attoui Houssam , Cantaloube Jean‐François , Dussol Bertrand , Berland Yvon , de Micco Philippe , Lamballerie Xavier de 
Published: September 2002

AbstractTT virus‐like minivirus (TLMV) was recently discovered as a human circovirus. Little is known about its natural history and molecular epidemiology. A study of TLMV infection is described in a population of French hemodialysis patients. TLMV DNA was tested by seminested PCR system located in the noncoding region in 81 patients divided into seven groups according to the origin of their renal disease. Quantitation of TLMV DNA in serum was carried out. Sequences from 28 patients were compared with 40 sequences retrieved from databases and 53 TLMV sequences cloned from the serum of a single patient. The prevalence of TLMV DNA in hemodialysis patients was 95.1%. In this study, 24 samples (29.6%) presented viral loads of > 125 equivalents of plasmid (Ep)/ml, and only 6 (7.8%) had viral loads of > 125 × 102 Ep/ml. A significant correlation (P < 0.029) was found between viral loads of > 125 × 102 Ep/ml and the neoplastic origin of end‐stage renal disease. Analysis of 53 sequences cloned from a single individual demonstrated high sequence variability, as shown by the genetic distance of 40.2%. This genetic distance is comparable to that between the most divergent sequences of TLMV reported to date (43.5%). These data suggest that TLMV viral load is possibly related to the level of immunocompetence of hemodialysis patients; the genetic diversity of TLMV is extremely high; and co‐infection by different strains is possible. J. Med. Virol. 67:630–635, 2002. © 2002 Wiley‐Liss, Inc.
Circular scanning and equivalent magnetic currents for main plane near‐field to far‐field transformation
Authors: Las‐Heras F. , Galocha B. , Besada J. L. 
Published: September 2002

AbstractA method to obtain a main plane far‐field radiation pattern of an antenna under test (AUT) from the correspondent main plane near‐field pattern in a circular scanning is presented. The method is based on the reconstruction of a set of magnetic equivalent currents radiating in free space that represents the AUT. The method can be applied to the measurement of antennas with a linear distribution or with a two‐dimensional distribution under certain considerations that allow to establish integral equations relating field components and one‐dimensional current components. A Levenberg–Marquardt algorithm is used to minimize the least squares error between the fields radiated by the equivalent currents and the measured field. The far field at every aspect angle is obtained from the calculated sources. Calculations of co‐polar and cross‐polar far‐field pattern from measured near‐field data of array antennas have been carried out to compare the proposed method with a full spherical scanning followed by a spherical wave expansion method. Copyright © 2002 John Wiley & Sons, Ltd.
Efficient gene transfer in mouse neural precursors with a bicistronic retroviral vector
Authors: Franceschini Isabelle A. , Feigenbaum‐Lacombe Valérie , Casanova Philippe , Lopez‐Lastra Marcelo , Darlix Jean‐Luc , Dubois Dalcq Monique 
Published: September 2002

AbstractGene transfer into neural precursors is a powerful approach to study the function of specific gene products during nervous system development. Here we describe a retrovirus‐based methodology to transduce foreign genes into mouse neural precursors. We used a high‐titer bicistronic retroviral vector that encodes a marker gene, placental alkaline phosphatase (plap), and a selection gene, neomycin phosphotransferase II (neoR), under the translational control of two retroviral internal ribosome entry segments. Transduction efficiency even without selection was up to 95% for multipotential neurospheres derived from embryonic striata and grown with basic fibroblast growth factor 2. Expression of plap and neoR was sustained with time in culture and upon differentiation into neurons, astrocytes, and oligodendrocytes, as shown by double immunofluorescence labeling with cell type‐specific markers, Western blotting, and neomycin resistance. However, levels of plap were decreased in differentiated oligodendrocytes. Transduction with the same vector of neonatal oligodendrocyte precursors grown in oligospheres consistently resulted in a lower proportion of plap‐immunoreactive cells and enhanced cell death in the absence of neomycin. However, plap expression was maintained in some differentiated oligodendrocytes expressing galactocerebroside or myelin basic protein. In that neurospheres can be easily expanded in vitro and factors enabling their differentiation into the three main central nervous system cell types are being elucidated, this methodology could be used in the future to produce large number of transduced, differentiated neural cells. J. Neurosci. Res. 65:208–219, 2001. © 2001 Wiley‐Liss, Inc.
Administration of FGF‐2 to embryonic mouse brain induces hydrocephalic brain morphology and aberrant differentiation of neurons in the postnatal cerebral cortex
Authors: Ohmiya Makoto , Fukumitsu Hidefumi , Nitta Atsumi , Nomoto Hiroshi , Furukawa Yoshiko , Furukawa Shoei 
Published: September 2002

AbstractFibroblast growth factor‐2 (FGF‐2) was injected into mouse cerebral ventricles at embryonic day (E) 14 in utero and its effects on developing brain morphology and expression of various cell‐ or differentiation‐associated protein markers in the cerebral cortex were examined. High doses of FGF‐2 (200 or 300 ng) caused encephalic alternations such as deformation of the calvarium, enlargement of the ventricular spaces, and thinning of the cerebral cortex. There was no gross abnormality in the alignment of the cerebral neuronal layers, however, both cell number and cell density of the upper layers (II/III) and the lower layers (IV–VI) of the cerebral cortex were increased. Brain‐derived neurotrophic factor (BDNF), tyrosine hydroxylase, nestin, and microtubule‐associated protein 2 were aberrantly or ectopically expressed in the deep areas of the cerebral cortex. A substantial number of these cells coexpressed these antigens. These observations demonstrate that a subpopulation of neurons in the cortical deep layer abnormally differentiated or partly sustained their immature state following a single administration of FGF‐2 at E14. Developmental analysis of localization of BDNF‐positive cells suggested that the abnormality started around P5. Furthermore, cell migration was not affected by FGF‐2 administration. FGF‐2 seems to play predominant roles in the proliferation of neuronal precursors and in neuronal differentiation in the developing mouse cerebral cortex even at relatively late stages of brain neurogenesis. J. Neurosci. Res. 65:228–235, 2001. © 2001 Wiley‐Liss, Inc.
Role of GluR2 expression in AMPA‐induced toxicity in cultured murine cerebral cortical neurons
Authors: Jensen Jette Bisgaard , Lund Trine Meldgaard , Timmermann Daniel B. , Schousboe Arne , Pickering Darryl S. 
Published: September 2002

Abstractα‐Amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptor (AMPA‐R)‐mediated neurotoxicity was studied in relation to subunit expression and the presence of Ca2+‐permeable receptor channels. AMPA‐mediated toxicity had two components: 1) a direct AMPA‐R‐mediated component, which was not due to Ca2+ influx through voltage‐gated Ca2+ channels, reversal of the Na+/Ca2+ exchanger or release of calcium from dantrolene‐sensitive intracellular Ca2+ stores, and 2) a minor, indirect component involving activation of NMDA receptor channels, because of glutamate release and removal of the Mg2+ block of the NMDA receptor on AMPA‐R stimulation. The involvement of Ca2+ influx through AMPA‐R was also examined. The number of neurons possessing Ca2+‐permeable AMPA‐R increased during culture development, concurrently with an increasing susceptibility for AMPA‐induced toxicity during development. GluR2(R) levels also increased during development, and channel blockers of Ca2+‐permeable AMPA‐R lacking the GluR2(R) subunit (spermine and philanthotoxin) failed to prevent neurotoxicity or increases in [Ca2+]i. Thus, the direct AMPA‐R‐mediated toxicity may be explained by initiation of cell death by Ca2+ fluxing through AMPA‐R containing GluR2(R). The components of direct AMPA‐R‐mediated toxicity are proposed to be 1) toxicity mediated by GluR2(R)‐lacking AMPA‐R and 2) toxicity mediated by low‐Ca2+‐permeability AMPA‐R containing GluR2(R). J. Neurosci. Res. 65:267–277, 2001. © 2001 Wiley‐Liss, Inc.
Variable galactocerebroside expression by human Schwann cells in dissociated and peripheral nerve explant cultures
Authors: Turnbull Victor J. , Petratos Steven , Papadopoulos Roula , Gonzales Michael F. , Ayers Margaret 
Published: September 2002

AbstractIt has been well established that rat Schwann cells down regulate their cell‐surface expression of galactocerebroside (GalC) in vitro under normal cell culture conditions. To determine whether human Schwann cells exhibit a similar down‐regulation of GalC in vitro we examined GalC expression in dissociated human Schwann cell cultures derived from normal adult peripheral nerve. Twenty‐four hours post‐dissociation up to 63% of human Schwann cells were found to express detectable levels of GalC on their surface whereas less than 8% of the Schwann cells expressed detectable levels of GalC at 14 days post‐dissociation. In contrast, after nearly 3 months of peripheral nerve explant culture, greater than 30% of human Schwann cells still retained their GalC expression. A similar pattern was also observed when analyzing Schwann cell purity with dissociated cultures exhibiting a rapid decrease in Schwann cell purity under normal culturing conditions although Schwann cell purity was found to be largely unaffected during the period of peripheral nerve explant culture. In summary, we found there was less variation in both GalC expression and Schwann cell purity with time in peripheral nerve explant cultures than dissociated cultures. J. Neurosci. Res. 65:318–321, 2001. © 2001 Wiley‐Liss, Inc.
The El Niño southern oscillation and long‐range forecasting of flows in the Ganges
Authors: Whitaker Douglas W. , Wasimi Saleh A. , Islam Shafiqul 
Published: September 2002

AbstractSeveral recent studies have shown that the El Niño–Southern Oscillation (ENSO) index has a significant influence on various climatic and hydrologic signals across the globe. This study attempts to identify the nature and strength of possible teleconnections between the Ganges River flow and ENSO, and to develop a model which can capture, at least in part, the natural variability of flow, and provide a large forecasting lead‐time. The motivation came from the fact that, in the past, hydrologic forecasts of the basin through rainfall‐runoff modelling could provide a lead‐time on the order of the basin response time, which is several days or so. Such a short forecasting lead‐time is not adequate to hedge against extreme events (flood or drought) in large river basins. This is, perhaps, the first attempt to relate flows in the Ganges with ENSO.Our analysis suggests that a significant relationship exists between the natural variability of the Ganges annual flow and ENSO index. Through further investigation, we show that the rate of change of ENSO index is also statistically related to the Ganges flow. A statistical model that combines all these indicators to forecast annual flow in the Ganges is proposed. This model uses current flow data, predicted ENSO data and its gradient to forecast flow in the Ganges with a forecasting lead‐time of 1 year. The model also provides a quantitative measure of forecasting uncertainty. A key advantage of this model is that it does not require rainfall and stream flow information from upstream areas and countries. We have used 45 years of data for model development and calibration, and 15 years of data for validation. It is encouraging to note that all four of the validation forecasts during the El Niño and La Niña events are within the 95% confidence intervals. These results demonstrate the strength of the proposed approach and suggest further exploration of this long‐range forecasting methodology for other major rivers in the world. Copyright © 2001 Royal Meteorological Society
Evolution of maritime continent thunderstorms under varying meteorological conditions over the Tiwi Islands
Authors: Beringer Jason , Tapper Nigel J. , Keenan Tom D. 
Published: September 2002

AbstractThe development of tropical island thunderstorms in the maritime continent were investigated over the Tiwi Islands to the north of the Australian continent. A satellite cloud climatology was developed to examine these island thunderstorms, locally known as Hectors. During the pre‐monsoon period of 1990 and 1991 Hectors were observed on 70% of days. These Hectors were observed to occur under two distinct environmental flow regimes. Under easterly flow, development occurred on the western end of the island and conversely under westerly flow, development occurred to the east. Hectors were also observed to have three distinct modes of development (Hector, suppressed and late developing) and one mode of non‐development (non‐Hector). Satellite cloud climatologies were developed and mean atmospheric characteristics were determined for each of these development modes. Hectors developed under conditions of moderate convective available potential energy, moderate shear and high moisture availability. Sub‐cloud layer winds were also thought to contribute to the structure of the storm. Non‐Hector and suppressed Hector days usually occurred after a previous convective disturbance such as a monsoon low or squall line and had typically low convective available potential energy and high values of convective inhibition. Conditions for late developing Hectors appeared to be conducive for thunderstorm development with high convective available potential energy and low values of convective inhibition. However, early initiation was suppressed by high shear conditions. Development in the late developing mode could be more intense than in other modes. Copyright © 2001 Royal Meteorological Society
Mesoscale precipitation variability in the region of the European Alps during the 20th century
Authors: Schmidli Jürg , Schmutz Christoph , Frei Christoph , Wanner Heinz , Schär Christoph 
Published: September 2002

AbstractThe purpose of this study is to construct and evaluate a new gridded analysis of precipitation that covers the entire region of the European Alps (43.2–48.8 ° N, 3.2–16.2 ° E), resolves the most prominent mesoscale variations (grid spacing 25 km) and extends with a monthly time‐resolution over most of the 20th century (1901–90). The analysis is based on a reconstruction using the reduced‐space optimal interpolation technique. It combines data from a high‐resolution network over a restricted time period (1971–90) with homogeneous centennial records from a sparse sample of stations. The reconstructed fields account for 78% of the total variance in a cross‐validation with independent data. The explained variance for individual grid points varies between 60 and 95%, with lower skills over the southern and western parts of the domain. For averages over 100 × 100 km2 subdomains, the explained variance increases to 90–99%. Comparison of the reconstruction with the CRU05 global analysis reveals good agreement with respect to the interannual variations of large subdomain averages (10 000–50 000 km2), some differences in decadal variations, especially for recent decades, and physically more plausible spatial patterns in the present analysis.The new dataset is exploited to depict 20th century precipitation variations and their correlations with the North Atlantic oscillation (NAO). A linear trend analysis (1901–90) reveals an increase of winter precipitation by 20–30% per 100 years in the western part of the Alps, and a decrease of autumn precipitation by 20–40% to the south of the main ridge. Correlations with the NAO index (NAOI) are weak and highly intermittent to the north and weak and more robust to the south of the main Alpine crest, indicating that changes in the NAOI in recent decades are not of primary importance in explaining observed precipitation changes. Copyright © 2002 Royal Meteorological Society
Changes in seasonal and annual high‐frequency air temperature variability in the Arctic from 1951 to 1990
Authors: Przybylak Rajmund 
Published: September 2002

AbstractA detailed analysis of intraseasonal (within season) and interannual (between years) temperature variability for the whole Arctic for the period 1951–90 is provided. For this purpose four temperature variables were used: average (TMEAN), maximum (TMAX) and minimum (TMIN) temperatures, and the diurnal temperature range (DTR). The source data for the analysis were the daily TMAX and TMIN for ten stations representing almost all climatic regions in the Arctic. The methods of calculation of temperature variability were mostly taken from Plummer (1996; Australian Meteorological Magazine 45: 233). Thus the results presented for the Arctic can be fully compared with existing results for the other parts of the world (China, the former USSR, the USA and Australia).Regional trends in intraseasonal and interannual temperature variability were mixed and the majority of them were insignificant. Trends in intraseasonal variability were positive in the Norwegian Arctic and eastern Greenland and negative in the Canadian and Russian Arctic. Small increases in interannual variability for all temperature variables were observed annually in the Norwegian Arctic and eastern Greenland, and in the Canadian Arctic. These were largely a result of increases in winter and transitional seasons respectively. On the other hand, opposite tendencies, both on a seasonal and an annual basis, occurred in the Russian Arctic. Statistically significant negative trends in intraseasonal variability were noted mainly in the Canadian Arctic, whereas such trends in interannual variability were noted mainly in the Russian Arctic.The absence of significant changes in intraseasonal and interannual variability of TMEAN, TMAX, TMIN and DTR is additional evidence (besides the average temperature) that in the Arctic in the period 1951–90 no tangible manifestations of the greenhouse effect can be identified. Copyright © 2002 Royal Meteorological Society.
Mid‐ to late Holocene relative sea‐level change in Poole Harbour, southern England
Authors: Edwards Robin J. 
Published: September 2002

AbstractA foraminiferal transfer function for mean tide level (MTL) is used in combination with AMS radiocarbon dated material to construct a record of relative sea‐level (RSL) change from Poole Harbour, southern Britain. These new data, based on multiple cores from duplicate sites, indicate four phases of change during the last 5000 cal. (calendar) yr: (i) rising RSL between ca. 4700 cal. yr BP and ca. 2400 cal. yr BP; (ii) stable to falling RSL from ca. 2400 cal. yr BP until ca. 1200 cal. yr BP; (iii) a brief rise in RSL from ca. 1200 cal. yr BP to ca. 900 cal. yr BP, followed by a period of stability; (iv) a recent increase in the rate of RSL rise from ca. 400–200 cal. yr BP until the present day. In addition, they suggest that the region has experienced long‐term crustal subsidence at a rate of 0.5 mm C14 yr−1. Although this can account for the overall rise in MTL observed during the past 2500 yr, it fails to explain the changes in the rate of rise during this period. This implies that the phases of RSL change recorded in the marshes of Poole Harbour reflect tidal range variations or ‘eustatic’ fluctuations in sea‐level. Copyright © 2001 John Wiley & Sons, Ltd.