bluuebunny/crossref_metadata_2025 huggingface dataset:
Insulin: in search of a syndrome
Authors: Ferrannini E. , Balkau B.
Published: March 2003

The insulin resistance syndrome has been defined as the clustering of hypertension, dyslipidaemia and impaired glucose tolerance in subjects with high fasting plasma insulin concentrations. The latter are usually taken as a surrogate measure of insulin resistance of whole‐body glucose disposal. Although hyperinsulinaemia and insulin resistance are reciprocally related to one another, the association is not very strong. In the data‐pooling project of the European Group for the study of Insulin Resistance (EGIR), clamp‐derived insulin sensitivity (as the M value) and fasting plasma insulin concentrations were available in 1,308 non‐diabetic subjects with a wide range of age and body mass index. In this cohort, hyperinsulinaemia (as the upper quartile of fasting plasma insulin distribution in the non‐obese segment of the population) and insulin resistance (as the bottom quartile of M value in the same subgroup) were each present in ~40% of the whole population, but identified only partially overlapping (60%) subsets of individuals. When the subjects with insulin resistance but without hyperinsulinaemia (n = 198) were compared with the subjects with hyperinsulinaemia but without insulin resistance (n = 267), significant differences emerged in the respective clinical phenotypes. Thus, subjects with ‘pure’ insulin resistance had a more central fat distribution and presented evidence of excessive lipolysis and endogenous glucose production. In contrast, subjects with ‘pure’ hyperinsulinaemia had suppressed lipolysis, endogenous glucose production and insulin clearance, higher values of systolic blood pressure and lower values of serum HDL‐cholesterol concentrations. The only abnormality common to both phenotypes was the presence of raised serum triglycerides concentrations.

This analysis indicates that hyperinsulinaemia and insulin resistance identify partially different subgroups of individuals in a non‐diabetic population, and suggests that hyperinsulinaemia and insulin resistance carry distinct pathogenic potential in terms of the components of the insulin resistance syndrome.
Symptom scoring systems to diagnose distal polyneuropathy in diabetes: the Diabetic Neuropathy Symptom score
Authors: Meijer J. W.G. , Smit A. J. , Sonderen E. V. , Groothoff J. W. , Eisma W. H. , Links T. P.
Published: March 2003

Aims To provide one of the diagnostic categories for distal diabetic polyneuro‐pathy,several symptom scoring systems are available, which are often extensive andlack in validation. We validated a new four‐item Diabetic Neuropathy Symptom (DNS) scorefor diagnosing distal diabetic polyneuropathy.

Methods We compared score characteristics of the generally accepted NeuropathySymptom Score (NSS) with the DNS score, and tested construct validity,predictive value and reproducibility with the Diabetic Neuropathy Examinationscore, Semmes–Weinstein monofilaments and Vibration Perception Threshold(clinical standards) in 73 patients with diabetes (24 Type 1, 49 Type 2;43 male/30 female; mean age 57 years (19–90);mean diabetes duration 15 years (1–43)).

Results Correlation between NSS and DNS score was high (Spearman r= 0.88). Patient scoreswere more differentiated on the DNS score. The relation of the NSS andDNS scores, respectively, with clinical standards was good (Spearman r= 0.21–0.60). Reproducibility ofthe DNS score was high (Cohen weighted κ 0.78–0.95). The DNSscore was easier to perform in clinical practice.

Conclusions The DNS is validated, fast and easy to perform, with a high predictive valuewhen screening for diabetic polyneuropathy.

Diabet. Med. 19, 962–965 (2002)
Tumour necrosis factor‐alpha plasma levels in elderly patients with Type 2 diabetes mellitus—observations over 2 years
Authors: Lechleitner M. , Herold M. , Dzien‐Bischinger C. , Hoppichler F. , Dzien A.
Published: March 2003

Aims The cytokine tumour necrosis factor‐alpha (TNF‐α) is involved in the development of obesity‐linked insulin resistance. TNF‐α plasma levels rise with increasing age and might thus also be related to metabolic control in Type 2 diabetes mellitus. We have studied the relationship of TNF‐α plasma levels to glycaemic control in elderly patients with Type 2 diabetes over 2 years.

Methods Clinical and laboratory data of 53 patients (26 women, 27 men) with Type 2 diabetes (mean age 71.6 ± 5.6 years) were regularly evaluated over 2 years, and the relationship to anti‐diabetic treatment regimens analysed. TNF‐α plasma level was measured by a solid‐phase enzyme amplified sensitivity immunoassay.

Results TNF‐α plasma levels increased significantly from 16.2 ± 9.6 pg/ml at baseline to 28.0 ± 13.8 pg/ml after 2 years (P = 0.028). HbA1c values also increased from 6.4 ± 1.2% to 7.7 ± 1.6% (P = 0.046). Mean body mass index of the patients remained almost constant, while a moderate increase in the percentage of body fat (34.5 ± 7.0% to 35.3 ± 6.9%; P= 0.061) and in waist–hip ratio was observed (0.86 ± 0.04 to 0.88 ± 0.04; P= 0.052). After adjustment for covariates multivariate analysis demonstrated that TNF‐α plasma levels are positively related to the HbA1c values of the whole study population at the baseline control and after 2 years. TNF‐α also revealed a positive correlation to the percentage of body fat.

Conclusions In elderly patients with Type 2 diabetes TNF‐α plasma levels revealed a continuous increase during an observation period of 2 years. This increase in TNF‐α plasma levels might add another aspect to the worsening of glycaemic control in the progression of Type 2 diabetes.

Diabet. Med. 19, 949–953 (2002)
Psychosocial factors and diabetes‐related outcomes following diagnosis of Type 1 diabetes in adults: The Edinburgh Prospective Diabetes Study
Authors: Taylor M. D. , Frier B. M. , Gold A. E. , Deary I. J.
Published: March 2003

Aims  To examine prospectively the relationships between psychosocial variables and diabetes‐related outcomes in adults with newly diagnosed Type 1 diabetes.

Methods  A total of 84 adults (48 male) with a median (range) age of 30.8 (17–51) years with newly diagnosed Type 1 diabetes were recruited for the study. Shortly after initial diagnosis each participant's personality, cognitive ability, and recent psychiatric distress were assessed. At 4 months (n = 69) and at 12 months (n = 66) after diagnosis diabetes‐related outcomes were measured, including each respondent's knowledge of diabetes, satisfaction with diabetes treatment and diabetes‐related quality of life. Glycated haemoglobin (HbA1c) was recorded at each clinic attendance.

Results  Social class (Spearman's correlation r = −0.30 and −0.28, respectively, P < 0.05) and scores on the National Adult Reading Test (r = 0.38 and 0.36, respectively, P < 0.01) were consistently associated with knowledge of diabetes at 4 months and at 12 months after diagnosis. Hierarchical regression revealed that alcohol consumption recorded at diagnosis and knowledge of diabetes at 4 months were independent predictors of glycaemic control at 12 months (adjusted r2 = 0.16). Total scores on the Diabetes Treatment Satisfaction Questionnaire (DTSQ) at 12 months were significantly predicted by age at diagnosis (adjusted r2 = 0.08). High neuroticism at diagnosis was consistently associated with poorer self‐reported diabetes quality of life at 4 months and at 12 months after diagnosis (rs between −0.30 and −0.39, P < 0.05).

Conclusions  Long‐standing psychosocial factors have a significant influence on self‐reported outcomes during the 12 months following diagnosis of Type 1 diabetes but may not be reliable predictors of glycaemic control. Further follow‐up is necessary to determine the longer‐term predictors of objective (e.g. glycaemic control) and subjective (e.g. quality of life) indicators of coping in people with diabetes.
Bioclimatic discriminant capacity of terrestrial mammal faunas
Authors: Fernández Manuel Hernández
Published: March 2003

A new method of environmental inference is presented. This method uses the climatic restriction index (CRI) for each mammal species, based on its geographical range within different climatic regimes, and a set of calculated summary indexes known as the bioclimatic spectrum. Analysis of 50 faunas throughout the world shows that terrestrial mammal communities are effective tools for accurate climatic inference at large spatial scale. The results also indicate that the use of entire mammalian fauna is the best inference system, followed by those based on separate groups such as Insectivora, Rodentia, micromammals and macromammals. Removing Chiroptera from the analysis does not change the results significantly. Bioclimatic analysis appears to be a good method for environmental interpretation. This new method ensures a high qualitative precision. It provides an empirical model for mammal community characterization that must be taken into account for palaeoclimatic reconstructions of continental environments.
Inter‐hemispheric synchrony of forest fires and the El Niño‐Southern Oscillation
Authors: Kitzberger Thomas , Swetnam Thomas W. , Veblen Thomas T.
Published: March 2003

Fire histories were compared between the south‐western United States and northern Patagonia, Argentina using both documentary records (1914–87 and 1938–96, respectively) and tree‐ring reconstructions over the past several centuries. The two regions share similar fire–climate relationships and similar relationships of climatic anomalies to the El Niño–Southern Oscillation (ENSO). In both regions, El Niño events coincide with above‐average cool season precipitation and increased moisture availability to plants during the growing season. Conversely, La Niña events correspond with drought conditions. Monthly patterns of ENSO indicators (southern oscillation indices and tropical Pacific sea surface temperatures) preceding years of exceptionally widespread fires are highly similar in both regions during the 20th century. Major fire years tend to follow the switching from El Niño to La Niña conditions. El Niño conditions enhance the production of fine fuels, which when desiccated by La Niña conditions create conditions for widespread wildfires. Decadal‐scale patterns of fire occurrence since the mid‐17th century are highly similar in both regions. A period of decreased fire occurrence in both regions from c. 1780–1830 coincides with decreased amplitude and/or frequency of ENSO events. The interhemispheric synchrony of fire regimes in these two distant regions is tentatively interpreted to be a response to decadal‐scale changes in ENSO activity. The ENSO–fire relationships of the south‐western USA and northern Patagonia document the importance of high‐frequency climatic variation to fire hazard. Thus, in addition to long‐term trends in mean climatic conditions, multi‐decadal scale changes in year‐to‐year variability need to be considered in assessments of the potential influence of climatic change on fire regimes.
Elevation gradients of diversity for rodents and bats in Oaxaca, Mexico
Authors: SÁnchez‐Cordero VÍctor
Published: March 2003

1 This study documents patterns of rodent and bat diversity related to abiotic and biotic factors along elevational gradients in the Sierra Mazateca (640–2600 m a.s.l.) and Sierra Mixteca (700–3000 m a.s.l.) in Oaxaca, Mexico.

2 The two transects share similar faunas: 17 and 23 rodent species were captured in the sierras Mazateca and Mixteca, respectively, 14 of which occurred on both transects. Rodent species richness was similar in the wet season and the dry season along both transects. Rodent species richness peaked at 1025–1050 m in tropical semi‐deciduous forest on both transects. Endemic species were restricted to high‐elevation habitats.

3 Sixteen and 17 bat species were captured in the sierras Mazateca and Mixteca, respectively; 11 occurred on both transects. Bat species richness was higher in the wet season than in the dry season in the Sierra Mazateca. Bat species richness peaked at 1850 m in pine–oak forest in the Sierra Mazateca, and at 750 m and 1050 m in tropical semi‐deciduous forest in the Sierra Mixteca, decreasing abruptly at higher elevations on both transects.

4 Patterns of trophic diversity of rodents and bats coincided with those of species richness on each transect. Species richness increased with increasing habitat diversity; increased with increasing rainfall and productivity; increased with increasing resource diversity; and increased in areas with high rates of speciation (rodents only).

5 The need for conservation action in Oaxaca is urgent and proponents should promote establishment of protected areas linking lowland habitats with high species richness to high‐elevation habitats harbouring large numbers of endemic forms.
Mapping the biomass of Bornean tropical rain forest from remotely sensed data
Authors: Foody Giles M. , Cutler Mark E. , McMorrow Julia , Pelz Dieter , Tangki Hamzah , Boyd Doreen S. , Douglas Ian
Published: March 2003

The biomass and biomass dynamics of forests are major uncertainties in our understanding of tropical environments. Remote sensing is often the only practical means of acquiring information on forest biomass but has not always been used successfully. Here the conventional approaches to the estimation of forest biomass from remotely sensed data were evaluated relative to techniques based on the application of artificial neural networks. Together these approaches were used to estimate and map the biomass of tropical forests in north‐eastern Borneo from Landsat TM data. The neural networks were found to be particularly suited to the application. A basic multi‐layer perceptron network, for example, provided estimates of biomass that were strongly correlated with those measured in the field (r = 0.80). Moreover, these estimates were more strongly correlated with biomass than those derived from 230 conventional vegetation indices, including the widely used normalized difference vegetation index (NDVI).
Pantropical dynamics of ‘intact’ rain forest canopy texture
Authors: Weishampel John F. , Godin Jason R. , Henebry Geoffrey M.
Published: March 2003

Aside from deforestation and selective logging, mature tropical rain forests appear to be in a state of near‐term flux. At plot scales over a 20‐year period, forest inventory data (representing areas < 750 ha) have shown stands to be accumulating above‐ground biomass pantropically while displaying signs of increasing turnover. To assess whether or not such disequilibrium is manifest at broader spatial scales (i.e. coarser grain sizes and larger extents), we performed a change detection analysis of landscape texture (i.e. the organization of reflective properties), in satellite images of closed‐canopy tropical rain forests considered to be anthropically undisturbed. Here we show that fractal properties of pixel spectral values depicting low and high levels of photosynthetic activity underwent significant shifts from the 1970s to the 1980s. Following expectations for aggrading forests, canopy texture became more random throughout the tropics. Although subject to periodic disturbance events such as natural exogenic perturbations and/or synchronous die‐off, which should produce no consistent trend, these forested landscapes across the globe exhibited similar dynamics at fine temporal (decadal) intervals. Such biophysical changes (representing areas > 1000 000 ha) directly affect atmospheric boundary layer conditions and could have implications with respect to biodiversity and carbon cycling in these systems.
Does precipitation variability increase from mesic to xeric biomes?
Authors: Davidowitz Goggy
Published: March 2003

Desert precipitation is often characterized as more variable than precipitation in nondesert biomes. However, empirical support for this generalization is lacking. I analysed precipitation variability in five desert and four nondesert biomes that represent a xeric to mesic gradient in the South‐western United States, using data from 328 weather stations, for a total of 18 337 station‐years. I examined precipitation variability at two temporal scales: among years and among months, within years. Each of these scales was analysed for annual precipitation, summer precipitation and winter precipitation for a total of 18 separate analyses. Overall, precipitation variability does increase as precipitation decreases. However, I found little support for the generalization that desert precipitation is more variable than precipitation in nondeserts. At most time scales, many south‐western American desert biomes are no more variable than nondesert biomes. The level of variability is highly dependent on which desert biome is under study, where in the biome a particular site is located, and what time scale is used to measure variability. Certain desert sites are in fact more variable than nondesert sites, in some cases by as much as fivefold. However, and perhaps more importantly, each desert biome includes many sites that are no more variable, across many or all time scales, than sites in the grassland or pine forest biomes. These results emphasize the importance of measuring variability for each study site of interest and caution against extrapolating from a few sites to biomes or gradients in general. Implications for the study of adaptations to environmental variability are discussed.
The effects of productivity and seasonality on life history: comparing age at maturity among moose (Alces alces) populations
Authors: Ferguson Steven H.
Published: March 2003

The productivity hypothesis in respect of an animal species’ geographical range predicts that whereas higher productivity at the equatorial periphery of a species’ range favours superior competitors, lower productivity at the centre of a species’ range favours high reproduction and reduced competitive traits. I test whether life‐history patterns follow this hypothesis, using demographic data from 15 Canadian moose (Alces alces) populations. Two models are contrasted; the first assumes that intraspecific variation in age at maturity is explained proximately by density and juvenile mortality. Age at maturity was found to increase with decreasing juvenile mortality (P = 0.01) and increasing density (P = 0.006). To test the productivity hypothesis, the second model additionally included primary productivity and seasonality as geographical explanatory variables that would ultimately influence age at maturity via juvenile mortality and density. Path analysis indicated that including productivity and seasonality improved the model predictions of variation in age at maturity (Ra20.56 and 0.85). In bivariate comparisons, seasonality was negatively associated (P = 0.01) with age at maturity. In the best model, however, primary productivity was the environmental variable that explained 25% of the variance in age at maturity, and forest cover replaced seasonality as an explanatory variable. The positive association between primary productivity and age at maturity is consistent with the productivity hypothesis. Relative to populations that lived at the centre of the species’ range (51°N), moose populations living in relatively high productivity and low seasonality environments (equatorial periphery of species’ range; 48°N) experienced less juvenile mortality, more variable year‐to‐year density, higher relative density and slower life history (slower growth rate, later age at maturity, lower fecundity).
The global distribution of cultivable lands: current patterns and sensitivity to possible climate change
Authors: Ramankutty Navin , Foley Jonathan A. , Norman John , McSweeney Kevin
Published: March 2003

Aim This study makes quantitative global estimates of land suitability for cultivation based on climate and soil constraints. It evaluates further the sensitivity of croplands to any possible changes in climate and atmospheric CO2 concentrations.

Location The location is global, geographically explicit.

Methods The methods used are spatial data synthesis and analysis and numerical modelling.

Results There is a cropland ‘reserve’ of 120%, mainly in tropical South America and Africa. Our climate sensitivity analysis indicates that the southern provinces of Canada, north‐western and north‐central states of the United States, northern Europe, southern Former Soviet Union and the Manchurian plains of China are most sensitive to changes in temperature. The Great Plains region of the United States and north‐eastern China are most sensitive to changes in precipitation. The regions that are sensitive to precipitation change are also sensitive to changes in CO2, but the magnitude is small compared to the influence of direct climate change. We estimate that climate change, as simulated by global climate models, will expand cropland suitability by an additional 16%, mainly in the Northern Hemisphere high latitudes. However, the tropics (mainly Africa, northern South America, Mexico and Central America and Oceania) will experience a small decrease in suitability due to climate change.

Main conclusions There is a large reserve of cultivable croplands, mainly in tropical South America and Africa. However, much of this land is under valuable forests or in protected areas. Furthermore, the tropical soils could potentially lose fertility very rapidly once the forest cover is removed. Regions that lie at the margins of temperature or precipitation limitation to cultivation are most sensitive to changes in climate and atmospheric CO2 concentration. It is anticipated that climate change will result in an increase in cropland suitability in the Northern Hemisphere high latitudes (mainly in developed nations), while the tropics will lose suitability (mainly in developing nations).
Assessing the vulnerability of species richness to anthropogenic climate change in a biodiversity hotspot
Authors: Midgley G.F. , Hannah L. , Millar D. , Rutherford M.C. , Powrie L.W.
Published: March 2003

Aim  To compare theoretical approaches towards estimating risks of plant species loss to anthropogenic climate change impacts in a biodiversity hotspot, and to develop a practical method to detect signs of climate change impacts on natural populations.

Location  The Fynbos biome of South Africa, within the Cape Floristic Kingdom.

Methods  Bioclimatic modelling was used to identify environmental limits for vegetation at both biome and species scale. For the biome as a whole, and for 330 species of the endemic family Proteaceae, tolerance limits were determined for five temperature and water availability‐related parameters assumed critical for plant survival. Climate scenarios for 2050 generated by the general circulation models HadCM2 and CSM were interpolated for the region. Geographic Information Systems‐based methods were used to map current and future modelled ranges of the biome and 330 selected species. In the biome‐based approach, predictions of biome areal loss were overlayed with species richness data for the family Proteaceae to estimate extinction risk. In the species‐based approach, predictions of range dislocation (no overlap between current range and future projected range) were used as an indicator of extinction risk. A method of identifying local populations imminently threatened by climate change‐induced mortality is also described.

Results  A loss of Fynbos biome area of between 51% and 65% is projected by 2050 (depending on the climate scenario used), and roughly 10% of the endemic Proteaceae have ranges restricted to the area lost. Species range projections suggest that a third could suffer complete range dislocation by 2050, and only 5% could retain more than two thirds of their range. Projected changes to individual species ranges could be sufficient to detect climate change impacts within ten years.

Main conclusions  The biome‐level approach appears to underestimate the risk of species diversity loss from climate change impacts in the Fynbos Biome because many narrow range endemics suffer range dislocation throughout the biome, and not only in areas identified as biome contractions. We suggest that targeted vulnerable species could be monitored both for early warning signs of climate change and as empirical tests of predictions.
Patterns of within‐species body size variation of birds: strong evidence for Bergmann's rule
Authors: Ashton Kyle G.
Published: March 2003

Aim The aim of this study is to test whether Bergmann's rule, a general intraspecific tendency towards larger body size in cooler areas and at higher latitudes, holds for birds throughout the world.

Location This study includes information on species of birds from throughout the world.

Methods I gathered data on body size variation from the literature and used two general meta‐analytical procedures to test the validity of Bergmann's rule in birds: a modified vote‐counting approach and calculation of overall effect sizes. Related species may show similar body size trends, thus I performed all analyses using nonphylogenetic and phylogenetic methods. I used tests of phylogenetic signal for each data set to decide which type of statistical analysis (nonphylogenetic or phylogenetic) was more appropriate.

Results The majority of species of birds (76 of 100 species) are larger at higher latitudes, and in cooler areas (20 of 22 species). Birds show a grand mean correlation coefficient of +0.32 for body size and latitude, and −0.81 for body size and temperature, both significant trends. Sedentary species show stronger body size trends in some, but not all, analyses. Neither males nor females consistently have stronger body size trends. Additionally, the strength of body size trends does not vary with latitude or body mass.

Conclusions Bergmann's rule holds for birds throughout the world, regardless of whether temperature or latitude (as a proxy) is used. Previous studies have suggested that Bergmann's rule is stronger for sedentary than migratory species, males than females and temperate than tropical taxa. I did not find strong support for any of these as general themes for birds, although few studies of tropical taxa have been conducted. The processes responsible for Bergmann's rule remain somewhat of a black box; however, fasting endurance is probably a more important factor than the traditional hypothesis of heat conservation.
A probabilistic approach to the use of pollen indicators for plant attributes and biomes: an application to European vegetation at 0 and 6 ka
Authors: Gachet S. , Brewer S. , Cheddadi R. , Davis B. , Gritti E. , Guiot J.
Published: March 2003

Aim This paper presents a probabilistic method for the characterization of pollen taxa using attributes, and for the reconstitution of past biomes. The probabilities are calculated on the basis of European floristic and pollen databases sufficiently large and exhaustive to provide robust estimates.

Location The analysis is based on data from approximately 1000 sites throughout Europe.

Method We use all the pollen data from the European Pollen Database (EPD), which contains about 50 000 pollen assemblages distributed across Europe and covering the period from the Last Glacial Maximum to the present. Using existing floras, each pollen taxon has been characterized by allocating one or more modes of several attributes, chosen according to the biogeography and phenology of the taxon. With this information, conditional probabilities are defined, representing the chance of a given attribute mode occurring in a given pollen spectrum, when the taxa assemblage is known. The concept of co‐occurrence is used to provide a greater amount of information to compensate for difficulties in the identification of pollen grains, allowing a better interpretation when there is little diversity in the pollen assemblage.

Results The method has been validated using a dataset of modern samples against existing methods of biome classification and remote sensing data. An application is proposed in which the new method is used to produce biomes for pollen data 6000 years ago. This confirms previous results showing an extension of the deciduous forest to the north, east and south, explained by milder winters in western and northern Europe, and cooler and wetter climate in the Mediterranean region.

Conclusion The results show the new method to be efficient, reliable and flexible and to be an improvement over the previous method of biomization. They will be used to test simulations of earth system models running on periods with climate significantly different from the present day, enabling a robust test of the validity of applying these models to the future.
Spatial autocorrelation and red herrings in geographical ecology
Authors: Diniz‐Filho José Alexandre Felizola , Bini Luis Mauricio , Hawkins Bradford A.
Published: March 2003

Aim Spatial autocorrelation in ecological data can inflate Type I errors in statistical analyses. There has also been a recent claim that spatial autocorrelation generates ‘red herrings’, such that virtually all past analyses are flawed. We consider the origins of this phenomenon, the implications of spatial autocorrelation for macro‐scale patterns of species diversity and set out a clarification of the statistical problems generated by its presence.

Location To illustrate the issues involved, we analyse the species richness of the birds of western/central Europe, north Africa and the Middle East.

Methods Spatial correlograms for richness and five environmental variables were generated using Moran's I coefficients. Multiple regression, using both ordinary least‐squares (OLS) and generalized least squares (GLS) assuming a spatial structure in the residuals, were used to identify the strongest predictors of richness. Autocorrelation analyses of the residuals obtained after stepwise OLS regression were undertaken, and the ranks of variables in the full OLS and GLS models were compared.

Results Bird richness is characterized by a quadratic north–south gradient. Spatial correlograms usually had positive autocorrelation up to c. 1600 km. Including the environmental variables successively in the OLS model reduced spatial autocorrelation in the residuals to non‐detectable levels, indicating that the variables explained all spatial structure in the data. In principle, if residuals are not autocorrelated then OLS is a special case of GLS. However, our comparison between OLS and GLS models including all environmental variables revealed that GLS de‐emphasized predictors with strong autocorrelation and long‐distance clinal structures, giving more importance to variables acting at smaller geographical scales.

Conclusion Although spatial autocorrelation should always be investigated, it does not necessarily generate bias. Rather, it can be a useful tool to investigate mechanisms operating on richness at different spatial scales. Claims that analyses that do not take into account spatial autocorrelation are flawed are without foundation.
Identifying and characterizing a five‐gene cluster of ATP‐binding cassette transporters mapping to human chromosome 17q24: a new subgroup within the ABCA subfamily
Authors: Arnould Isabelle , Schriml Lynn M. , Prades Catherine , Lachtermacher‐Triunfol Marcia , Schneider Thomas , Maintoux Christelle , Lemoine Cendrine , Debono Delphine , Devaud Catherine , Naudin Laurent , Bauché Stéphanie , Annat Mélanie , Annilo Tarmo , Allikmets Rando , Gold Bert , Denèfle Patrice , Rosier Marie , Dean Michael
Published: March 2003

Introduction

The ATP‐binding cassette (ABC) gene superfamily encodes a series of transporter proteins that move a wide variety of substances across extra‐ and intracellular membranes. Forty‐eight known human ABC genes can be divided into seven phylogenetically distinct subfamilies. The ABCA gene subfamily is found exclusively in multicellular eukaryotes.

Results

We report here on a unique tandem array of five ABCA genes on chromosome 17q24 defining a phylogenetically distinct group. This is the largest cluster of mammalian ABC genes described to date. They are arranged head‐to‐tail and have similar intron/exon organization in both mouse and human. Northern analysis reveals a heterogeneous pattern of expression in human tissues, with ABCA5 and ABCA10 expressed in skeletal muscle, ABCA6 in the liver, ABCA9 in the heart, and ABCA8 in ovaries. This suggests that these proteins have distinct functions.
Subclinical cerebral involvement in Behçet's disease: a SPECT study
Authors: Avci O. , Kutluay E. , Argon M. , Erdem S. , Guüneş A. Tahsin
Published: March 2003

Neurologic involvement has been reported in Behçet's disease (BD) with prevalence rates of 4–49%. Involvement of the central nervous system (CNS) usually follows systemic manifestations of BD by months to years, but as the initial future in only 5% of cases. The variance of the prevalence rates of neurologic involvement in BD raises the possibility of subclinical neurologic involvement. For the purpose of explaining the variance in the prevalence rates, 20 patients with BD, but without neurological symptoms and signs, were investigated by using cerebral single photon emission computed tomography (SPECT) which seems to be more convenient for BD than other scanners. A control group of patients with various diseases that were not expected to influence the cerebral blood flow was included. Brain magnetic resonance imaging (MRI) scans were performed in cases in which abnormal SPECT findings were obtained. Decreased and asymmetrical tracer uptakes were detected in 35% of patients with BD. MRI scans were normal in these patients. We concluded that functional imaging using SPECT may detect abnormalities at an initial stage prior to their progression to morphological damage detectable by MRI, and this imaging modality can be used even in cases which show no neurologic symptom to indicate the subclinical neurologic involvement.
Quantitative techniques for lesion load measurement in multiple sclerosis: an assessment of the global threshold technique after non uniformity and histogram matching corrections
Authors: Molyneux P.D. , Wang L. , Lai M. , Barker G.J. , Tofts P.S. , Moseley I.F. , Miller D.H.
Published: March 2003

The quantitative assessment of abnormalities on brain MRI (magnetic resonance imaging) in multiple sclerosis (MS) provides a widely used endpoint in monitoring treatment efficacy. Semi‐automated intensity thresholding (global thresholding) is an established method of lesion segmentation, but it is limited by the heavy dependence of derived volumes on the chosen intensity threshold. Inconsistency in threshold choice substantially contributes to its suboptimal reproducibility. A potential improvement to global thresholding is to utilize the histogram matching algorithm to correct for variations in scanner sensitivity. This study evaluated whether or not a single intensity threshold could then be applied across multiple histogram matched images. Eight MS patients were scanned at baseline and after nine months. After nonuniformity correction, the histogram matching correction was applied, reducing the mean absolute percentage variation in normal appearing white matter signal intensity from 15.2 to 3.8% for baseline scans and from 11.9 to 2.1% across serial studies. Lesion volumes were measured with the global threshold technique using a single threshold selected from one scan. A local thresholding technique (contouring) was also performed as a gold standard measure. Agreement between techniques for baseline lesion volumes was only moderate with an intra‐class correlation coefficient (ICC) of 0.46 and there was little agreement for change in lesion volume (ICC = 0.17), reflecting inconsistencies in the volume of non‐lesion regions included by the threshold. Agreement was improved by deleting non‐lesion regions, but this was time consuming and less reproducible than contouring method. At present, the contour technique remains a more appropriate method for lesion load quantification.
Acute primary cerebral angiitis mimicking basilar artery dissection
Authors: Kruisdijk J.J.M. , Vanneste J.A.L.
Published: March 2003

Two patients presented with acute severe occipital headache, neck pain, nausea, vomiting and blurred vision. In both patients angiograms of the posterior circulation showed focal narrowing of the basilar artery, thus basilar artery dissection was considered. Urgent magnetic resonance imaging (MRI) was unavailable. On the basis of additional angiography of the anterior circulation and control angiograms after 4 and 6 weeks, primary cerebral angiitis was the most probable diagnosis. Treatment with corticosteroids resulted in rapid clinical and angiographic improvement. We conclude that, when MR techniques are unavailable or inconclusive, presumption of basilar dissection on the base of clinical features, Doppler studies, Duplex scanning and angiography of the vertebro‐basilar system should be confirmed by additional carotid angiography in order to exclude diffuse cerebral angiitis.
Effects of TRH on ballistic wrist movements in cerebellar cortical atrophy: improvement of two genuine deficiencies but not of the major one
Authors: Manto M. , Godaux E. , Hildebrand J. , Jacquy J.
Published: March 2003

Thyrotropin‐releasing hormone (TRH) has been claimed to improve cerebellar ataxia in patients with idiopathic sporadic cerebellar cortical atrophy (CCA). We analysed the effects of intravenous administration of TRH (1 mg) in ballistic wrist flexions movements in 10 healthy subjects and in eight patients with CCA. The associated agonist and antagonist electromyographic (EMG) activities were recorded. In healthy subjects, TRH did modify neither the movement amplitudes, nor the intensity of the agonist and antagonist EMG activities. Before TRH administration, patients with CCA exhibited a hypermetria which was associated with a delayed onset of the antagonist activity. Moreover, the intensity of EMG activity in both the agonist and the antagonist muscles were reduced. After TRH, the hypermetria and the delayed onset latencies of the antagonist EMG activities were unchanged but the intensity of both the agonist and the antagonist EMG activities increased. TRH could increase the magnitude of agonist and antagonist EMG activities in patients with CCA by exerting an excitatory effect directly on motoneurons or by modulating at the supraspinal level the central commands to agonist and antagonist motoneuron pools.
A comparison of the spread of three formulations of botulinum neurotoxin A as determined by effects on muscle function
Authors: Dodd S.L. , Rowell B.A. , Vrabas I.S. , Arrowsmith R.J. , Weatherill P.J.
Published: March 2003

The purpose of these experiments was to compare the spread of three formulations of botulinum neurotoxin A. A gelatin/phosphate buffer (C), DysportR (D {0.5 U}, BotoxR (B {0.167 U}), or a purified preparation of botulinum neurotoxin A [Bont A] (BA {0.5 U}) was injected into the tibialis anterior of male, Wistar rats. After 4 days, the adjacent extensor digitorum longus muscle was isolated in situ and the nerve was maximally stimulated to determine contractile properties and the rate of fatigue. There were no differences in body or muscle weights between any of the groups after 4 days of treatment. Maximal twitch and tetanic tensions were decreased ≈ 25% (p < 0.05) in all treatment groups compared to C. In addition, rate of tension development was significantly less in all treatment groups compared to C but one‐half relaxation time and time to peak tension were not different between any groups. Fatigue of the muscle was significantly faster in all groups compared to C but there was no difference between treatment groups. These data indicated that botulinum toxin A injected intramuscularly was likely to spread to adjacent muscles but that the spread was not different between the three formulations tested. The effect of the spread ranged from a slight to a severe reduction in maximal tension but this did not occur in all animals studied.
A double‐blind, placebo‐controlled, randomized, multi‐center study of pramipexole in advanced Parkinson's disease
Authors: Wermuth L. ,   The Danish Pramipexole Study Group
Published: March 2003

Pramipexole (SND 919), a potent non‐ergot dopamine agonist, or placebo, was administered to 69 patients with advanced Parkinson's disease (33 received placebo, 36 received pramipexole) in a double‐blind, randomized, multi‐center study in which individually optimized doses of l‐dopa plus a dopa decarboxylase inhibitor were associated with dyskinesia, “on–off” fluctuation, dystonia, akinesia, or end‐of‐dose deterioration. Study medication was titrated over 7 weeks to the maximal tolerated dose or to the maximal dose allowed by the study (5 mg/day in four divided doses). Dosing was maintained for 4 weeks and then tapered during the final week. Total score on the Unified Parkinson's Disease Rating Scale (UPDRS) for the intent‐to‐treat population was significantly improved in the pramipexole‐treated group compared with the placebo‐treated group (16.9 ± 14.9 vs 9.0 ± 16.1; p= 0.0184). By the end of maintenance, the mean reduction in l‐dopa requirement was −150.7 mg for pramipexole‐treated patients compared to −10.6 for placebo‐treated patients. The most common adverse events (> 10%) were dizziness, insomnia, nausea, and postural hypotension. Aggravated parkinsonism occurred only after withdrawal of the study medication. Treatment with pramipexole in doses up to 5 mg/day was safe and well tolerated by patients with advanced Parkinson's disease.
Changing Mortality of Cerebral Haemorrage
Authors: CHOUDARY ZAHID I. , CHAN MICHAEL T.Y. , BARSOUM S. , NORRIS J.W.
Published: March 2003

The previous decline of the incidence of stroke is now less apparent. Most of this decline was in ischaemic stroke; the changes in haemorrhagic stroke are less certain.

We have documented on our stroke data bank in Toronto the stroke frequency. We collected retrospective data of 182 admissions for cerebral haemorrhage. 126 (69%) were direct admissions to emergency and 56 (31%) were referral. In hospital mortaility rate was higher in the emergency group than in the referral group (52% vs 19.6%). Moreover, patients from the referral group were found to have predominant lobar haemorrhage and less proportion of central lesion. In 1976, 10.1% of strokes admitted rate in the week was 47%. In 1997, 10% of strokes were haemorrhagic but the mortality rate was 37% (P > 0.05).

Although some of these differences probably represent referral bias, these data indicate a decline in mortality but not incidence.
Cost Effectiveness of t‐PA Therapy
Authors: NADAREISHVILI ZURAB G. , SMARAWSKA LILIANA T. , NORRIS JOHN W.
Published: March 2003

Although the effect of t‐PA treatment in acute cerebral infarction remains controversial, there is evidence based data that it may prove effective if given early and with appropriate criteria.

We have calculated the cost of t‐PA treatment in Canada assuming that 35 000 of the 50 000 yearly stroke incidence is due to acute ischemic stroke. The cost of treating one patient is about $7 000 CDN, and the cost effectiveness depends upon the number of eligible patients. At present in our region in Toronto, about 20% of these arrive in the emergency room of a tertiary care hospital within 3 hours.

With regional stroke centres such as those in Canada, we calculate that with this degree of eligibility there would be considerable cost‐savings.
Charcot‐Marie‐Tooth disease type 1 and 2‐an immunohistochemical study of muscle fibre cytoskeletal proteins and a maker for muscle fibre cytoskeletal proteins and a marker for muscle fibre regeneration
Authors: Ericson UllaBritt , Ansved Tor , Borg Kristian
Published: March 2003

In 10 patients with Charcot‐Marie‐Tooth disease type 1 (CMT1), hereditary motor and sensory neuropathy (HMSN) type, 1, deymyelinating form, and 10 patients with CMT2, HMSN type 2, axonal form, monoclonal antibodies directed against dystrophin, spectrin, desmin, vimentin and a myoblast and satellite‐cell related antigen, Leu‐19, were applied to muscle biopsies from the anterior tibial muscle. Data from the biopsies were compared with those from 20 age‐and sexmatched healthy controls, Both CMT1 and CMT2 patients had normal stainings for dyustrophin and spectrin, indicating a normal muscle fibre cytoskeletal structure. In the CMT2 group, seven patients had increased staining for desmin in the majority of the atrophic fibres. In the CMT1 group, six of the patients had a normal desmin stating in normal sized and in atrophic muscle fibres, while the remaining four patients had an increased staining for a desmin in a few atrophic muscle fibres. Seven CMT2 patients and one CMT1 patient had increased staining of vimentin in some atrophic muscle atrophi muscle fibres. These immunohistochemical data support earlier findings of muscle fibre histopathological differences in CMT1 and CMT2 patients, possible reflecting different pathophysiological mechanisms in the two disorders.
Ideomotor apraxia test: a new test of imitation of gestures for elderly people
Authors: Dobigny‐Roman N. , Dieudonne‐moinet B. , Tortrat D. , Verny M. , Forotte B.
Published: March 2003

Ideomotor apraxia is one the earliest disturbances in Alzheimer's disease(AD); no test of this disturbance has yet been validated for elderly people. We propose a test of meaningless gesture imitation and its relevance;in elderly people is studied. The Ideomotor Aprazia Test (IAT) consists of showing 10 gestures. Each item is graded from 0 to 3. IAT was carried;out on 55 patients with AD (mean age:86.8 ± 6.8(71–100); mean MMS score: 14.6 ± 6.3) and 26 elderly patients without cognitive impairment (mean age:84.1 ± 7.5(70–100); mean MMS score:27.5 ± 1.9). The inter‐rater relilability, a threshold, the apparent sensitivity and specificity and the relationship bestween the MMS score and the ideomotor apraxia score were determined. The mean apraxia score was 14.9 ± 7.3 in the AD group and 28 ± 1.6 in the normal group (P < 0.0001). Inter‐rater agreement is excellent (P = 0.995). The threshold is 27. The apparent sensitivity and specificity are very good (95% and 98%, respectively). The correlataion between the MMS score and ideomotor apraxia score. IAT is the first test that evaluates meaningless gesture imitating capacity in an elderly population. It is easy and quick‐to‐perform test, useful routienly for diagnois of AD and is correlatead with the severity of cognitive impairment.
Myopathy in two siblings with nephropathic cystinosis
Authors: Kastrup O. , Koeppen S. , Schwechheimer K. , Keidel M. , Diener H. C.
Published: March 2003

Nephropathic cystinosis is a hereditary disorder characterized by a specific defect in the transport of cystine across the lysosomal membrane leading to an accumulation of protein‐free cystine in tissues including conjuctiva liver bone marrow and kidney. Renal transplantation is necessary because of renal failure. With improved life‐expectancy neurological complications have been reported including cases of distal myopathy diagnosed ante‐and post mortem. We report on two further rare cases of two siblings suffering from cystinosis who developed a predominantly distal myopathy proven electrophysiologically and on biopsy during life. The reported clinical picture of a distal atrophy resembling a neurogenic disease confirms a picture apparently typical in cystinosis. Possible effects of cysteamine therapy on the course of the myopathy are discussed.
Atypical brachial plexopathy with pseudotumor cerebri
Authors: Awada Adnan , Obeid Tahir , Jumah Mohamed Al , Ghanmi Hussein Al
Published: March 2003

A 24‐year‐old woman with previously known pseudotumor cerebri syndrome (PTCS) presented with severe pain in the neck and shoulders followed by the classical symptoms and signs of bilateral brachial neuritis. At the same time, there was a recurrence of the PTCS which had been in remission for more than one‐and‐a‐half years. Despite treatment with high doses of methylprednisolone, intravenous immunoglobulins and repeated cerebrospinal fluid drainage, both brachial plexopathy and the PTCS continued to worsen. Both lumbosacral plexuses became involved and the visual acuity deteriorated to a level such that a lumboperitoneal shunt had to be inserted. The neurological condition started to improve progressively after 8 weeks. This case is, to our knowledge, the first where brachial plexopathy has been described in association with a PTCS. Although the pathogenesis of this association is not clear, there are enough data to suggest the existence of a continuum between extended brachial plexopathy and Guillain Barré syndrome, with which PTCS has been associated in some instances.