bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of ephedrine on the onset time of succinylcholine
Authors: Ganidagli S. , Cengiz M. , Baysal Z. 
Published: October 2004

Background:  The aim of this study was to evaluate the effect of ephedrine administered prior to induction of anaesthesia on the onset time of succinylcholine for endotracheal intubation.Methods:  Patients were randomly assigned to receive intravenously (i.v.) either 70 µg kg−1 of ephedrine (Group I; n = 25) or saline (Group II; n = 25) 3 min before induction of anaesthesia. Induction of anaesthesia was provided with propofol 2 mg kg−1 plus remifentanil 1 µg kg−1. Onset time and duration of muscle fasciculation and onset time of succinylcholine were recorded. Intubation was attempted after establishment of 100% thumb relaxation and difficulties were recorded. Heart rate, pulse oxymetry (SpO2) and mean arterial pressure (MAP) were also recorded.Results:  The onset time of succinylcholine were significantly (P < 0.001) shorter in Group I (26 ± 4 s), when compared with Group II (43 ± 6 s). Patients in Group I were intubated at 49 ± 7 s compared with 68 ± 10 s in Group II. The score of intubation was similar in both groups. Duration of muscle fasciculation was longer in Group II. Heart rate and MAP increased significantly (P < 0.05) after ephedrine injection, compared with the baseline value in Group I.Conclusions:  The onset time of succinylcholine can be shortened with ephedrine pretreatment.
An extended probabilistic approach of plant vital attributes: an application to European pollen records at 0 and 6 ka
Authors: Gritti E. S. , Gachet S. , Sykes M. T. , Guiot J. 
Published: October 2004

ABSTRACTAim  This paper presents a probabilistic method of pollen spectra analysis. The method relies on a pollen taxon characterization using biotic and abiotic plant attribute modes, and their occurrence in a given pollen spectrum at a specific site. This type of analysis can provide an interpretation, which can lead to the reconstruction of the biome and, to an extent, of the abiotic conditions at the site.Methods  The analysis has been carried out at the European scale using data provided by the European Pollen Database for about 1000 sites. This dataset contains about 50,000 pollen spectra from the last 21 ka. In these spectra, each pollen taxon has been characterized by a set of 10 chosen attributes. These have been selected with regard to their relevance in biome reconstruction, but also on the basis of available literature. By using the probability of occurrence of each taxon in a given pollen spectrum, it is possible to calculate an affinity index for the spectrum to the attribute considered. To overcome difficulties caused by pollen identification in low diversified pollen spectra, a co‐occurrence concept has been used to give more information.Results  The method has been validated on a set of 1327 modern surface samples by comparing the results to the major climatic and environmental variables that control the distribution of the vegetation. A reconstruction exercise on various characteristics of the plants was then carried out on a 6‐ka dataset. This confirmed previous studies by showing a strong dominance of deciduous forest over most of Europe, related to a milder climate than at present in the north and a wetter and colder climate than at present in the south. By analysing the change in pollen/seed dispersion strategies and the light requirement, we show that the history of vegetation dynamics in relation to human influences can be assessed using this method.Main conclusions  Our results show that the probabilistic method is an objective tool for pollen assemblage analysis. It allows reconstruction of various characteristics of the vegetation at the continental and global scale for periods and sites with significantly different climate conditions. This method can also be used to compare maps of vegetation attributes for the validation of the new generalized dynamic ecosystems models.
Modelling the distribution and interaction of introduced rodents on New Zealand offshore islands
Authors: Russell James C. , Clout Mick N. 
Published: October 2004

ABSTRACTAim  To establish the factors that correlate with the distribution of the four most commonly introduced rodent species on New Zealand offshore islands — ship rat (Rattus rattus), Norway rat (R. norvegicus), Pacific rat or kiore (R. exulans) and house mouse (Mus musculus) — and examine if these distributions are interactive at the archipelago scale.Location  The 297 offshore islands of the New Zealand archipelago (latitude: 34° S to 47° S; longitude: 166° E to 179° E).Methods  Data on the distribution of all four introduced rodent species and the characteristics of New Zealand offshore islands were collated from published surveys and maps. The distribution of individual rodent species was regressed on island characteristics using a logistic generalized linear model. Interactions were examined by including the distributions of other rodent species as predictors in models.Results  All four rodent species appear to be limited by a variety of factors, which differ between species in both number and type. The distribution of ship rats is limited by the most factors, reflecting the extent of its distribution across the archipelago. The distribution of mice is the least explicative. Only the three rat species interacted in their distribution. The distribution of kiore on offshore islands is significantly negatively related to that of ship rats and to a lesser extent Norway rats. The distribution of mice did not appear affected in any way by the number of other rodent species on an island.Main conclusions  Differences in competitive ability and dispersal allow all four species to inhabit the New Zealand archipelago. Kiore distribution appears to be most limited by ship rat (and to a lesser extent Norway rat) distribution. The distribution of kiore was not found to interact with the distribution of mice on offshore islands, as has been suggested by others. The distribution of mice on offshore islands was difficult to model, which highlights the difficulties in managing this species. Overall the results offer valuable insights for management methods to assist preventing the invasion of offshore islands.
Rarity, commonness, and patterns of species richness: the mammals of Mexico
Authors: Vázquez Luis‐Bernardo , Gaston Kevin J. 
Published: October 2004

ABSTRACTAim  To determine whether rare or common species contribute most to overall patterns of spatial variation in extant species richness.Location  Mexico.Methods  Using data on the distribution of mammal species across Mexico at a quarter degree resolution, we ranked species from the most widespread to the most restricted (common‐to‐rare) within the study area, and from the most restricted to the most widespread (rare‐to‐common), and generated a sequence of patterns of species richness for increasing numbers of species. At each stage along both series of richness patterns, we correlated the species richness pattern for the subassemblage with that of the full assemblage. This allows comparison of subassemblages of the n most common with the n most rare species, in terms of how well they match the full assemblage richness pattern. Further analyses examined the effects on these patterns of correlation of the amount of raw information contained in the distributions of given numbers of rare and common species.Results  For the mammals of Mexico the more widely distributed species contribute disproportionately to patterns of species richness compared with more restricted species, particularly for non‐volant species and endemic species. This is not simply a consequence of differences in the volumes of information contained in the distributions of rare and common species, with the disproportionate contribution of common species if anything being sharpened when these differences are taken into account. The pattern is most clearly demonstrated by endemic species, suggesting that the contribution of common species is clearest when the causes of rarity and commonness are limited to those genuinely resulting in narrow and widespread geographical ranges, respectively, rather than artificial (e.g. geopolitical) boundaries to the extents of study regions.Conclusions  Perhaps surprisingly, an understanding of the determinants of overall patterns of species richness may gain most from consideration of why common species occur in some areas and are absent from others, rather than consideration of the distributions of rare species.
The carrying capacity of ecosystems
Authors: Del Monte‐Luna Pablo , Brook Barry W. , Zetina‐Rejón Manuel J. , Cruz‐Escalona Victor H. 
Published: October 2004

ABSTRACTWe analyse the concept of carrying capacity (CC), from populations to the biosphere, and offer a definition suitable for any level. For communities and ecosystems, the CC evokes density‐dependence assumptions analogous to those of population dynamics. At the biosphere level, human CC is uncertain and dynamic, leading to apprehensive rather than practical conclusions. The term CC is widely used among ecological disciplines but remains vague and elusive. We propose the following definition: the CC is ‘the limit of growth or development of each and all hierarchical levels of biological integration, beginning with the population, and shaped by processes and interdependent relationships between finite resources and the consumers of those resources’. The restrictions of the concept relate to the hierarchical approach. Emergent properties arise at each level, and environmental heterogeneity restrains the measurement and application of the CC. Because the CC entails a myriad of interrelated, ever‐changing biotic and abiotic factors, it must not be assumed constant, if we are to derive more effective and realistic management schemes. At the ecosystem level, stability and resilience are dynamic components of the CC. Historical processes that help shape global biodiversity (e.g. continental drift, glaciations) are likely drivers of large‐scale changes in the earth's CC. Finally, world population growth and consumption of resources by humanity will necessitate modifications to the paradigm of sustainable development, and demand a clear and fundamental understanding of how CC operates across all biological levels.
Synergism between Amodiaquine and Its Major Metabolite, Desethylamodiaquine, againstPlasmodium falciparumIn Vitro
Authors: Mariga S. T. , Gil J. P. , Sisowath C. , Wernsdorfer W. H. , Björkman A. 
Published: October 2004

ABSTRACTThe in vitro activity of the prodrug amodiaquine and its metabolite monodesethyl-amodiaquine has been studied for three strains ofPlasmodium falciparum: LS-2, LS-3, and LS-1. Both compounds showed significant activity against all three strains; the activity of amodiaquine was slightly higher than that of the metabolite. By use of a checkerboard design, interaction studies with both compounds yielded evidence of significant synergism; means of the sums of the fractional inhibitory concentrations were 0.0392 to 0.0746 for strain LS-2, 0.1567 to 0.3102 for strain LS-3, and 0.025 to 0.3369 for strain LS-1. In further investigations, the interaction of amodiaquine with monodesethyl-amodiaquine was tested at clinically relevant concentrations of both compounds. In these studies, involving amodiaquine at picomolar and femtomolar concentrations, the compound was found to exert high potentiating activity on monodesethyl-amodiaquine. This interaction produced mean ratios of observed to expected activity of 0.0505 to 0.0642 for strain LS-2, 0.0882 to 0.3820 for strain LS-3, and 0.0752 to 0.2924 for strain LS-1. The synergistic activity was most marked at monodesethyl-amodiaquine/amodiaquine ratios up to 100,000:1 but was still evident at higher ratios.
Modified Fixed-Ratio Isobologram Method for Studying In Vitro Interactions between Atovaquone and Proguanil or Dihydroartemisinin against Drug-Resistant Strains of
Plasmodium falciparum
Authors: Fivelman Quinton L. , Adagu Ipemida S. , Warhurst David C. 
Published: October 2004

ABSTRACT
A modified fixed-ratio isobologram method for studying the in vitro interactions between antiplasmodial drugs is described. This method was used to examine the interactions between atovaquone, proguanil, and dihydroartemisinin. The interaction between atovaquone and proguanil was synergistic against atovaquone-sensitive strains K1 and T996; however, there was a loss of synergy against atovaquone-resistant strain NGATV01 isolated after Malarone (the combination of atovaquone and proguanil) treatment failure. While the interaction between atovaquone and dihydroartemisinin was indifferent against isolate NGATV01, the interaction displayed indifference tending toward antagonism against the atovaquone-sensitive strains tested. The relevance of in vitro interactions to in vivo treatment is discussed.
Emergence of Multidrug-Resistant
Salmonella enterica
Serovar Typhi in Korea
Authors: Lee Kyungwon , Yong Dongeun , Yum Jong Hwa , Lim Young Sik , Kim Hyun Sook , Lee Bok Kwon , Chong Yunsop 
Published: October 2004

ABSTRACT

A chloramphenicol-resistant strain of
Salmonella enterica
serovar Typhi was first noted in Korea in 1992, when a resistant isolate was detected in a returned traveler. Continued isolation of multidrug-resistant (MDR) strains thereafter in other settings prompted a retrospective analysis of laboratory records and phenotypic and genotypic analyses of 12 chloramphenicol-resistant isolates. Among these, one isolate was resistant only to chloramphenicol, and the other isolates were also resistant to ampicillin and co-trimoxazole. MDR was transferred by conjugation from 9 of the 11 isolates. PCR showed that all isolates had an incompatible group HI1 plasmid, and
oriT
was detected in 10 isolates, which included strains with an unsuccessful transfer of resistance. All of the ampicillin-resistant isolates had a β-lactamase band of pI 5.4 and
bla
TEM
alleles. A PCR amplicon from an isolate showed that the sequences were identical to those of
bla
TEM-1
, suggesting that all isolates had a TEM-1 β-lactamase. All isolates had class 1 integrons: 10 isolates had integrons of ca. 1.2 kb with
dhfr7
gene cassettes, and 1 isolate had an integron of ca. 2.3 kb with
aacA4
and
bla
OXA-1
-like gene cassettes. The pulsed-field gel electrophoresis patterns of 7 of 11 MDR isolates were identical and indistinguishable from those reported for isolates in India and Indonesia. In conclusion, some of the MDR strains in Korea are related to those in other Asian countries. Susceptibility testing became necessary for selection of antimicrobial agents for the optimal treatment of patients with the emergence of MDR
Salmonella
serovar Typhi in Korea.
Four Variants of the
Citrobacter freundii
AmpC-Type Cephalosporinases, Including Novel Enzymes CMY-14 and CMY-15, in a
Proteus mirabilis
Clone Widespread in Poland
Authors: Literacka Elżbieta , Empel Joanna , Baraniak Anna , Sadowy Ewa , Hryniewicz Waleria , Gniadkowski Marek 
Published: October 2004

ABSTRACT

Twenty-nine
Proteus mirabilis
isolates from 17 Polish hospitals were analyzed. The isolates were resistant to a variety of antimicrobials, and their patterns of resistance to β-lactams resembled those of the constitutive class C cephalosporinase (AmpC) producers. Indeed, β-lactamases with a pI of ∼9.0 were found in all of the isolates, and they were subsequently identified as four AmpC-type cephalosporinases, CMY-4, -12, -14, and -15, of which the two last ones were novel enzyme variants. The enzymes were of
Citrobacter freundii
origin and were closely related to each other, with CMY-4 likely being the evolutionary precursor of the remaining ones. The
bla
CMY
genes were located exclusively in chromosomal DNA, within EcoRI restriction fragments of the same size of ∼10 kb. In the CMY-12- and -15-producing isolates, an additional fragment of ∼4.5 kb hybridized with the
bla
CMY
probe as well, which could have arisen from a duplication event during the evolution of the genes. In all of the isolates, the IS
Ecp1
mobile element, which most probably is involved in mobilization of the
C. freundii ampC
gene, was placed at the same distance from the 5′ ends of the
bla
CMY
genes, and sequences located between them were identical in isolates carrying each of the four genes. These data suggested that a single chromosome-to-chromosome transfer of the
ampC
gene from
C. freundii
to
P. mirabilis
could have initiated the spread and evolution of the AmpC-producing
P. mirabilis
in Poland. The hypothesis seems to be confirmed by pulsed-field gel electrophoresis typing, which revealed several cases of close relatedness between the
P. mirabilis
isolates from distant centers and showed an overall similarity between the majority of the multiresistant isolates.
Effects of Amoxicillin Subinhibitory Concentrations on the Cross-Protection Developed by Pneumococcal Antibodies in Mouse Sepsis Caused by an Amoxicillin-Resistant Serotype 6BStreptococcus pneumoniaeStrain
Authors: Tarragó D. , Aguilar L. , Giménez M. J. , Fenoll A. , Casal J. 
Published: October 2004

ABSTRACTA model of mouse sepsis caused by a serotype 6BStreptococcus pneumoniaestrain (amoxicillin MIC of 8 μg/ml) was developed to investigate the therapeutic effect of an amoxicillin dose (3.12 mg/kg of body weight three times daily for 48 h) producing, over the whole treatment period, subinhibitory concentrations in serum (peak concentration [Cmax]: 6.1 μg/ml) in animals that prior to infection had been passively immunized with a 6B or 23F hyperimmune serum (obtained by immunization with a whole-cell heat-inactivated inoculum and diluted to produce no protective effect by itself). Mortality in nonimmunized animals treated with antibiotic (3.12 mg/kg) was 90%, and mortality in animals immunized but not treated with the antibiotic was 100%. Antibiotic treatment in immunized animals produced mortality rates ≤20% when the hyperimmune serum was used, thus showing cross-protection and synergism (defined as the situation in which there is no response to the single agents [no differences versus placebo] while the combination exhibits significant activity) with subinhibitory concentrations of the antibiotic. The presence of antipneumococcal antibodies allowed antibiotic efficacy with negligible values of pharmacodynamic parameters (Cmax/MIC ratio of <1 and thus a null value for the time that serum levels exceed the MIC). This in vivo synergism offers a potential therapeutic strategy against resistant strains.
Nevirapine Significantly Reduces the Levels of Racemic Methadone and (R)-Methadone in Human Immunodeficiency Virus-Infected Patients
Authors: Stocker Hartmut , Kruse Guido , Kreckel Peter , Herzmann Christian , Arastéh Keikawus , Claus Jörg , Jessen Heiko , Cordes Christiane , Hintsche Bettina , Schlote Frank , Schneider Lothar , Kurowski Michael 
Published: October 2004

ABSTRACTMethadone is metabolized by various isoforms of the cytochrome P450 family, which can be induced by many drugs, including nevirapine. The objective of the present study was to determine the effects of coadministration of nevirapine and methadone on the dose-adjusted areas under the concentration-time curves (AUCs) of racemic and (R)-methadone. Twenty-five human immunodeficiency virus-infected subjects taking stable single daily doses of racemic methadone or (R)-methadone were included in this prospective, single-crossover trial. At the baseline, nevirapine was either started as part of a new regimen containing two nucleoside reverse transcriptase inhibitors (NRTIs) or added to an ongoing NRTI regimen. Patients could increase their methadone doses if withdrawal symptoms developed. Twelve-hour pharmacokinetic profiles were obtained before and 28 days after the start of nevirapine treatment. The total concentrations of methadone and its inactive metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), in serum were determined by liquid chromatography-tandem mass spectrometry. Among the 20 evaluable patients, coadministration of nevirapine significantly decreased the mean dose-adjusted AUC of methadone by 41%. AUC reductions were similar for patients taking racemic methadone (37%;n= 11) and (R)-methadone (44%;n= 9). AUC changes ranged from mild increases in three patients to decreases of up to 70%. Fourteen of 20 patients required additional methadone due to withdrawal symptoms. However, the median dose increase was only 15%, which was less than that which would have been expected from the pharmacokinetic data. The AUC of EDDP increased significantly, by 35%. Methadone dose adjustments are justified when methadone is coadministered with nevirapine. Due to extensive variability, the adjustments must be tailored to the individual patient's needs.
Novel Chemical Class of pUL97 Protein Kinase-Specific Inhibitors with Strong Anticytomegaloviral Activity
Authors: Herget Thomas , Freitag Martina , Morbitzer Monika , Kupfer Regina , Stamminger Thomas , Marschall Manfred 
Published: October 2004

ABSTRACT

Human cytomegalovirus (HCMV) is a major human pathogen frequently associated with life-threatening disease in immunosuppressed patients and newborns. The HCMV UL97-encoded protein kinase (pUL97) represents an important determinant of viral replication. Recent studies demonstrated that pUL97-specific kinase inhibitors are powerful tools for the control of HCMV replication. We present evidence that three related quinazoline compounds are potent inhibitors of the pUL97 kinase activity and block in vitro substrate phosphorylation, with 50% inhibitory concentrations (IC
50
s) between 30 and 170 nM. Replication of HCMV in primary human fibroblasts was suppressed with a high efficiency. The IC
50
s of these three quinazoline compounds (2.4 ± 0.4, 3.4 ± 0.6, and 3.9 ± 1.1 μM, respectively) were in the range of the IC
50
of ganciclovir (1.2 ± 0.2 μM), as determined by the HCMV green fluorescent protein-based antiviral assay. Importantly, the quinazolines were demonstrated to have strong inhibitory effects against clinical HCMV isolates, including ganciclovir- and cidofovir-resistant virus variants. Moreover, in contrast to ganciclovir, the formation of resistance to the quinazolines was not observed. The mechanisms of action of these compounds were confirmed by kinetic analyses with infected cells. Quinazolines specifically inhibited viral early-late protein synthesis but had no effects at other stages of the replication cycle, such as viral entry, consistent with a blockage of the pUL97 function. In contrast to epithelial growth factor receptor inhibitors, quinazolines affected HCMV replication even when they were added hours after virus adsorption. Thus, our findings indicate that quinazolines are highly efficient inhibitors of HCMV replication in vitro by targeting pUL97 protein kinase activity.