bluuebunny/crossref_metadata_2025_split huggingface dataset:
Patterns of isozyme variation as indicators of biogeographic history in Pilgerodendron uviferum (D. Don) Florín
Authors: Premoli A. C. , Souto C. P. , Rovere A. E. , Allnut T. R. , Newton A. C. 
Published: March 2003

Abstract.The effects of Pleistocene glaciations on the genetic characteristics of the most austral conifer in the world, Pilgerodendron uviferum, were analysed with specific reference to the hypothesis that the species persisted locally in ice‐free areas in temperate South America. It was expected that genetic variation would decrease with latitude, given that ice fields were larger in southern Patagonia and thus refugia were probably located towards the northern distributional limit of the species as suggested by the fossil record. In addition, an increase in among‐population genetic divergence was expected with increasing distance to putative glacial refugia. We examined the relationship between location and within‐population variability indices of 20 Pilgerodendron populations derived from isozyme analyses. We analysed possible refugia hypotheses by the distribution of allele frequencies using multivariate discriminant analysis. The degree of genetic differentiation with geographical distance between all population pairs was investigated by Mantel tests. Results indicated that Pilgerodendron populations are highly monomorphic, probably reflecting past population bottlenecks and reduced gene flow. Southernmost populations tend to be the least genetically variable and were therefore probably more affected by glacial activity than northern ones. Populations located outside ice limits seem to have been isolated during the glacial period. The presence of centres of genetic diversity, together with the lack of a significant correlation between genetic and geographical distances and the absence of geographical patterns of allelic frequencies at most analysed alleles, may indicate that Pilgerodendron did not advance southward after the last glaciation from a unique northern refugium, but spread from several surviving populations in ice‐free areas in Patagonia instead.
Taxonomic resolution of the genus Bythotrephes Leydig using molecular markers and re‐evaluation of its global distribution
Authors: Therriault Thomas W. , Grigorovich Igor A. , Cristescu Melania E. , Ketelaars Henk A. M. , Viljanen Markku , Heath Daniel D. , Macisaac Hugh J. 
Published: March 2003

Abstract. Bythotrephes Leydig is a predatory, onychopod cladoceran native to Eurasia that typically inhabits oligo‐ and mesotrophic water bodies of the Palaearctic region. It recently invaded 70 North American lakes, prompting a re‐evaluation of the taxonomic status, global distribution, and determinants of local occurrence and abundance. European studies have reported two distinct species, B. longimanus, which lacks a kink on the caudal process, and B. cederstroemi, which possesses one. We employed sequencing of the mitochondrial gene cytochrome c oxidase subunit I (COI) in addition to Directed Amplification of Minisatellite‐region DNA (DAMD) using polymerase chain reactions (PCRs) to assay the genetic nature of these ‘species’. These analyses revealed that the two taxa are consistent with a single, common species, Bythotrephes longimanus Leydig 1860, thus resolving the nomenclatural issue. Furthermore, a common haplotype was identified between Lake Ontario and Lake Puruvesi, Finland, suggesting a potential invasion corridor via the nearby Baltic Sea. Statistical analysis revealed that the two forms also occur in similar habitats in Eurasia and North America. Habitat characteristics of water bodies in Northern Europe, where both forms are found and occasionally co‐occur, do not differ statistically. Similarly, no significant differences were detected between characteristics of Eurasian habitats that support longimanus‘forms’ and those of inland lakes in North America that support cederstroemi‘forms’. Human activities have had a strong effect on the distribution of Bythotrephes in both Europe and North America. Global and local distributions have been affected by ballast water transfer and by boating and fishing activities, respectively. Cultural eutrophication, oligotrophication and acidification alter the suitability of habitats for fish predators, and may indirectly influence Bythotrephes’ local occurrence and abundance.
Substitution patterns in congeneric arachnid species in the northern Alps
Authors: Muster Christoph 
Published: March 2003

Abstract.Complementary abundance gradients of substituting congeneric arachnids along the northern margin of the Alps are described, and the possible historical and contemporary factors that have produced these distributions are explored. The intensities of activity of epigeous arachnids were determined in pitfall traps along seven altitudinal transects approximately 35 km apart in the Bavarian Alps (Germany) and in the county of Salzburg (Austria). No supraregional gradient of physical factors exists within the region investigated. Six pairs of congeners show vicariances or alternating abundance gradients. For each species pair, the abundance gradient is represented in diagrams and compared with a graphic model of substitution types. Three patterns are evident: strict vicariances, abrupt replacement in a narrow belt, and gradual substitution over a wide zone of sympatric occurrence. The different extent of range overlap suggests distinctive classes and intensities of interspecific interactions. With regard to biogeographic histories, one prevailing pattern emerged: endemic species of the eastern Alps are replaced by Eurosiberian counterparts towards the west. It appears that geographical abundance variation reflects colonization history.
The role of Late Holocene climate variability in the expansion of yellow birch in the western Great Lakes region
Authors: Jackson Stephen T. , Booth Robert K. 
Published: March 2003

Abstract. Pollen records from the western Great Lakes region of North America show substantial increases in birch pollen percentages during the late Holocene. The vegetational and population dynamics underlying the birch increase have received little attention, in part because of the inability to discriminate among species of birch based on pollen morphology. We used analyses of pollen and plant macrofossils from four lakes in the Upper Peninsula of Michigan to document that the birch pollen increase represents a regional expansion of yellow birch (Betula alleghaniensis) populations, which was initiated c. 4500 years ago. Whether yellow birch invaded the region at this time or simply expanded from small, previously established populations is not clear, although it probably did not grow near our study sites before the expansion. The initial expansion occurred during an independently documented period of high moisture and high water levels in Lake Michigan. A subsequent expansion in yellow birch abundance and distribution occurred c. 3000 years ago, coinciding with a second period of increased moisture and high lake‐levels. The yellow birch expansion may have been modulated by millennial‐scale climate variability, with most rapid expansion occurring during relatively wet periods.
Beta‐blocker treatment in heart failure
Authors: Bouzamondo A , Hulot J S , Sanchez P , Cucherat M , Lechat P 
Published: March 2003

Heart failure treatment has markedly changed during the last few decades, with demonstration of benefit of afterload reduction by vasodilator therapy and introduction of the concept of the deleterious consequences of the neuro‐hormonal compensatory stimulation. Blockade of beta‐adrenergic receptors, initially contra‐indicated in heart failure, provide a marked reduction of mortality and morbidity in combination with diuretics and angiotensin‐converting enzyme inhibitors, as demonstrated in many clinical trials.We performed a review of all clinical trials that compare beta‐blockers vs. placebo in chronic heart failure. Beta‐blockers with different pharmacological profiles have been tested, mainly metoprolol, bisoprolol, bucindolol and carvedilol. With progressive dose increment, tolerance of such treatment was generally good, left ventricular function improved, hospitalisations for heart failure were less frequent and mortality was reduced. The meta‐analysis of the 16 randomised trials, with at least one death in each treatment group, provides a 24% relative risk reduction for such hospitalisations (95% CI=19%–29%) and 22% reduction for mortality (95% CI=16%–28%). Heterogeneity of beta‐blocker effect for mortality was found and related to the non‐significant benefit obtained in the BEST trial with bucindolol. When such a trial is excluded, the effect model analysis shows that relative risk reduction (beta‐blocker induced benefit) is constant whatever the severity of the disease. The mechanism of beta‐blocker induced benefit remains unclear, but is at least partly related to left ventricular function improvement and prevention of severe ventricular arrhythmias.In conclusion, beta‐blocker treatment has become an established therapy for heart failure, in combination with diuretics and ACE inhibitors. Complementary informations will be needed to clarify the mechanism of benefit and to define the best therapeutic strategy according to the individual characteristics of patients with heart failure.
Gender differences in adverse drug reactions: analysis of spontaneous reports to a Regional Pharmacovigilance Centre in France
Authors: Montastruc Jean‐Louis , Lapeyre‐Mestre Maryse , Bagheri Haleh , Fooladi Atoussa 
Published: March 2003

AbstractThe aim of this study was to investigate putative gender‐related differences in adverse drug reactions (ADRs). Data were ADRs recorded in the database of the French Midi‐Pyrénées Pharmacovigilance Centre in 1998. A total of 927 ADRs were spontaneously reported to the Centre in 1998, of which 53.1% were in females (difference vs. males not statistically significant). There was no statistically significant difference in the incidence of reported ADRs in males (3.6/10 000 inhabitants) vs. females (3.9/10 000 inhabitants) for the total population of the Midi‐Pyrénées area. The number of reported ADRs was similar across different age groups (10‐year age ranges). However, ‘serious’ ADRs were more frequently reported in males in the 0–9 and 60–69 age groups (and in females between 20 and 29 years old). There were significantly more neuropsychiatric (69 vs. 43, P=0.05) and fewer cardiovascular (8 vs. 2, P=0.05) ADRs reported in females than in males. ADRs were more frequently reported in females for some classes of drugs (such as genito‐urinary, sex hormone, antineoplastic, antiparasitic and respiratory drugs). These results confirm that female gender is a risk factor for the development of ADRs.
Effects of nicardipine and clonidine on cognitive functions and electroencephalography in hypertensive patients
Authors: Denolle T. , Sassano P. , Allain H. , Bentué‐Ferrer D. , Breton S. , Cimarosti I. , Ouatara B. , Merienne M. , Gandon J.‐M. 
Published: March 2003

AbstractThe aim of this study was to investigate the cognitive and electroencephalography (EEG) short‐term effects of a calcium antagonist, nicardipine, compared to placebo and clonidine (which, having known sedative effects, acted as a negative control) for 15 days in elderly hypertensive patients with memory complaints. Nicardipine and clonidine were compared with placebo in a double‐blind, randomized, three‐way cross‐over controlled study after a 2‐week placebo run‐in period. This was a phase II clinical study carried out on out‐patients in a single research centre. Fifteen elderly (63 ± 10 years) hypertensive patients, without dementia but with memory complaints, were included. Psychomotor performance and cognition were assessed using both an extensive battery of validated psychometric tests (which evaluated attention and vigilance, body sway and memory) and an EEG profile. Cardiovascular parameters measured were blood pressure and heart rate. No detrimental effects of nicardipine were found on attention, vigilance, body sway or memory. Nicardipine produced a significant increase in alpha EEG energies, which may indicate possible alerting effects. In contrast, clonidine induced well‐known deleterious sedative effects in psychometric tests and in EEG analysis (decrease in alpha and increase in delta and theta waves). The two drugs produced equivalent decreases in blood pressure at steady state. In conclusion, clonidine induced well‐known sedative effects, while nicardipine did not impair central nervous system activity and may have had some short‐term alerting effects in elderly hypertensive patients with memory complaints. This study supports the hypothesis of a dissociation between blood pressure and direct drug effects on the central nervous system.
Piribedil‐induced sleep attacks in Parkinson's disease
Authors: Tan E. K. 
Published: March 2003

Abstract‘Sleep attacks’, episodes of sudden onset of sleep without any prodromal symptoms, were initially described in patients with Parkinson's disease (PD) taking the newer dopamine agonists pramipexole and ropinirole. Piribedil, a nonergot agonist with both D2 and D3 agonist action, is an effective antiparkinsonian medication. However, there are very few reports of Piribedil‐induced sleep attacks in PD. Among 50 PD patients seen at our Movement Disorder Clinic who had recently taken Piribedil, we identified three (6%) who satisfied the clinical description of sleep attacks. Here we provide details of the clinical characteristics of Piribedil‐induced sleep attacks in these PD patients.
Lower reference limit for maximal oxygen uptake in men and women
Authors: Davis James A. , Storer Thomas W. , Caiozzo Vincent J. , Pham Patrick H. 
Published: March 2003

SummaryMaximal oxygen uptake (O2max) is an important measure of exercise tolerance and low values may have clinical significance. Our purpose was to develop the necessary statistics – prediction equations and standard errors of estimate (SEE) – so that the lower reference limit for O2max can be predicted for men and women. The subjects were healthy, non‐smoking, sedentary men (n=115) and women (n=115) aged 20–70 years who performed 15 W min−1 cycle ergometer exercise tests. Three equations were developed for each gender using multiple linear regression with the non‐exercise predictor variables of age and height, age and mass, and age and fat‐free mass (FFM). The assumptions of regression analysis were examined and the predicted residual sum of squares (PRESS) method was used to cross‐validate each equation. Healthy and diseased individual subject data from the literature were used to externally validate our lower reference limit statistics. The equations developed meet the assumptions of regression analysis and have an accuracy similar to the non‐exercise prediction equations in the literature with R2 values of ∼0·581. The PRESS method revealed that the equations are generalizable, i.e. may be used in future studies without a significant loss of accuracy. The lower reference limit predictions for the healthy and diseased individual subject data from the literature produced few miscategorizations unless the subjects were obese and mass was used as a predictor variable. In conclusion, the equations and SEE generated in this study can be used to predict an accurate and valid O2max lower reference limit for a given subject.
Simultaneous non‐invasive assessment of arterial stiffness and haemodynamics – a validation study
Authors: Kööbi Tiit , Kähönen Mika , Iivainen Tiina , Turjanmaa Väinö 
Published: March 2003

SummaryThe purpose of the study was to estimate the reliability of whole‐body impedance cardiography (ICGWB)‐derived pulse wave velocity (PWV) and stroke volume index to pulse pressure (SI/PP) measurements. The repeatability and reproducibility of ICGWB parameters were also determined. Agreement between the impedance and Doppler ultrasound‐based PWV measurements was estimated in 25 healthy subjects in two consecutive measurements. Impedance‐derived SI/PP (SIICG/PP) estimates were compared with simultaneously measured SI/PP based on thermodilution (SITD/PP) and direct Fick (SIFICK/PP) methods in 30 surgical patients. PWV measured between the aortic arch and popliteal artery using the impedance technique with selective electrode configuration (PWVIS) agreed well with the Doppler ultrasound method (PWVDOPP), the bias (PWVDOPP – PWVIS) and precision (± SD of differences) being 0·00 and 0·79 m s−1, respectively. PWV derived from the whole‐body and popliteal impedance plethysmograms (PWVICG) overestimated slightly PWVDOPP values. The repeatability value for PWVIS was excellent, being 0·54 m s−1. The reproducibility values for PWVDOPP and PWVIS were very similar (2·17 and 2·42 m s−1, respectively). Changes in PWVIS correlated strongly with changes in PWVDOPP (r=0·74; P<0·0001), indicating that both methods reflected the true physiological variation in PWV. The agreement between SIICG/PP and SITD/PP or SIFICK was almost identical to the agreement between the SITD/PP and SIFICK/PP. In conclusion,whole‐body impedance cardiography provides handy and reliable means of evaluating arterial stiffness on the basis of PWV and SI/PP simultaneously with conventional haemodynamic parameters. The method is highly repeatable and reproducible.
Rarity and Vulnerability: The Birds of the Cordillera Central of Colombia
Authors: KATTAN GUSTAVO H. 
Published: March 2003

Abstract: The rarity of an organism is widely accepted as a good predictor of vulnerability, but rarity has been interpreted in a variety of ways. Rabinowitz et al. (1986) defined three dimensions of rarity for an analysis of the flora of the British Isles geographic distribution, habitat specificity, and local population size. They found the three factors to be independent, that is, each factor provides information not provided by the other two. In this paper, the method of Rabinowitz et al. is used to analyze the vulnerability of the cloud forest avifauna of the Cordillera Central of Colombia The method is extended by assigning a vulnerability index to each form of rarity and analyzing its taxonomic and ecological correlates.I found that the three factors are not independent. Species with wide geographic distribution tend to have broad habitat specificity and high population densities. One‐third of the species have low population density, and most of these have restricted habitat specificity and narrow geographic ranges. Forty‐five percent of the birds in this sample are highly vulnerable because they have narrow distributions and require forest habitats.The taxonomic and ecological analyses reveal that some groups of species are particularly vulnerable. Among insectivorous birds, woodcreepers, spinetails, and antbirds seem to be very vulnerable becuse they depend on forest habitats. Raptors show no clear pattern, but for frugivores a clear pattern emerges. Some families (e.g., parrots, cotingas), seem to be consistently vulnerable, independent of body size. Tanagers show a significant correlation between body size and vulnerability. An analysis of local vulnerability (determined by habitat specificity and population size, regardless of distribution) reveals that frugivorous birds of restricted habitat specificity are significantly larger. Similar findings have been reported by other studies.The three‐dimensional classification of rarity used in this study provides a rapid, albeit preliminary, approach to identifying vulnerable species. To develop management practices adapted to each particular case, careful analysis of life history traits and detailed population and community studies are required.
An American Invasion of Great Britain: The Case of the Native and Alien Squirrel (Sciurus) Species
Authors: USHER MICHAEL B. , CRAWFORD TERENCE J. , BANWELL JEAN L. 
Published: March 2003

Abstract: The invasion of Great Britain by the gray squirrel from America has posed many interesting problems in ecology and conservation (interactions with the native red squirrel) and in forest management (the gray squirrel severely damages young stands of deciduous trees). Since 1973, mapped data on the annual distribution of the two species in state‐managed forests have been published by the Forestry Commission.Using the established methodology of annual ornithological index numbers, series of index numbers have been calculated to show the distributional dynamics of the two species. In Great Britain as a whole there has been rather limited change over the 15‐year period from 1973. However, this masks (1) the dramatic distributional decline in the red squirrel in Wales balanced by a modest expansion in Scotland, and (2) the substantial distributional increase in the gray squirrel in the small number of grid squares in Scotland in comparison with the relatively steady distribution in the large number of grid squares in England.A new index, measuring the annual replacement of one species by the other species, indicates little overall change in England and Scotland, but a net advance of the gray squirrel in Wales. A series of Markovian matrices predicted that the red squirrel would persist in forests in Scotland and in some areas of England, but would be rare in Wales. Over Great Britain as a whole, the gray squirrel is likely to occur in about twice as many forest areas as the red squirrel.
Assessment of the Environmental Risk Posed by an Exotic Fish: The Proposed Introduction of Channel Catfish (Ictalurus punctatus) to New Zealand
Authors: TOWNSEND COLIN R. , WINTERBOURN MICHAEL J. 
Published: March 2003

Abstract: In 1987, a proposal was made to introduce channel catfish (Ictalurus punctatus) into New Zealand for aquaculture. An environmental impact assessment in support of the proposal incorporated details of channel catfish biology, its value to people, diseases, the history of introductions elsewhere, and possible impacts on New Zealand biota should the species become established in the wild. Although information on the environmental impacts of channel catfish introduced to other countries was limited and inadequate for assessing potential effects on freshwater ecosystems in New Zealand, a permit was granted to import fertilized eggs. These were hatched in quarantine, and subject to the favorable outcome of environmental trials were to be released for aquaculture. Subsequently, the requirement for trials was abandoned and instead an independent, two‐man review team (the authors) was appointed to advise the Minister of Fisheries on whether the environmental risk posed by channel catfish was acceptable. The team considered the impact assessment and additional submissions from interested parties. The team concluded that there was a high probability that fish would escape and that they would be capable of breeding and growing in a wide range of freshwater environments throughout much of New Zealand.Because channel catfish are omnivorous, they would probably prey on at least some native fish species and introduced salmonids, invertebrates including freshwater crayfish, and aquatic macrophytes. Competition to the detriment of other fishes was also considered likely. Furthermore, the low species diversity and ecological simplicity of fish communities in New Zealand could allow channel catfish opportunities not found within their natural range, as in parts of western North America where they have had significant impacts on freshwater communities. Because the evidence indicated that one or more valued species was likely to suffer a decline in abundance or distribution if channel catfish were introduced, the review team recommended that the environmental risk posed by the fish was unacceptable. The recommendation was accepted by the Minister of Fisheries and all the channel catfish held in quarantine were destroyed. This case clearly demonstrated weaknesses in the importation procedure in New Zealand and subsequently some changes have been made. In general, we recommend a four‐step importation procedure comprising (1) environmental impact assessment, (2) publicity, (3) independent review, and (4) implementation. We suggest that the second step is most crucial.