bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial genotype and insect fitness in an aphid–bacterial symbiosis
Authors: BIRKLE L. M. , MINTO L. B. , WALTERS K. F. A. , DOUGLAS A. E.
Published: July 2004

The impact of the genotype of symbiotic micro‐organisms on ecologically important traits of their animal hosts was explored using the symbiosis between aphids and the bacteriumBuchnera. This symbiosis has a nutritional basis, with aphids dependent onBuchnera‐derived essential amino acids. The genetic variation studied was copy number of theBuchneragenestrpEG, coding for anthranilate synthase in the biosynthetic pathway of the essential amino acid tryptophan.TrpEGamplification has been predicted to enhance tryptophan biosynthesis rates byBuchnera.

TrpEGamplification ofBuchneravaried from 2 to 16‐fold relative to othertrpgenes among aphids from natural populations of the Pea AphidAcyrthosiphon pisum(Harris).

The fitness of aphids onVicia fabaplants of low phloem tryptophan content under field conditions and on tryptophan‐free chemically defined diets under laboratory conditions did not vary significantly withtrpEGcopy number ofBuchnera. It is concluded that naturally occurring variation intrpEGcopy number does not have large and readily detectable effects on aphid fitness.

This first study on the impact of genetic diversity ofBuchneraon ecologically important traits of the insect host illustrates the importance of empirical checks on the validity of plausible inferences made from genomic or other molecular data.
Control of tiller recruitment in bunchgrasses: uniting physiology and ecology
Authors: TOMLINSON K. W. , O'CONNOR T. G.
Published: July 2004

Bunchgrasses are clonal plants whose dominance of moist grasslands worldwide is maintained largely through tiller recruitment. Tiller recruitment in clonal plants is a subset of the problem of lateral bud outgrowth in higher plants. This paper proposes that three currently competing hypotheses of lateral bud outgrowth – apical dominance; the nutrition hypothesis; and photosensitivity to the red : far‐red light ratio – all operate in a manner dependent on environment and plant form.

The evidence for each hypothesis is reviewed, following which an integrated model is provided that links the three hypotheses into a cohesive strategy. Consequently we assess tiller recruitment by bunchgrasses in terms of the constraints of their functional growth form and their environment. Of the mineral nutrients, only nitrogen is considered because it is the only nutrient whose relationship with tiller recruitment is well established.

The integrated model maintains the accepted paradigm that actual bud release is hormonally controlled by the auxin : cytokinin ratio, although local nutrient concentrations may also be inhibitory. Importantly, each hormone is controlled by local signals in the shoots and roots, respectively, facilitating appropriate responses to environmental conditions. Auxin production and export from the shoots is moderated by phytochrome responses to red : far‐red light ratios. Cytokinin production is mediated by root N concentration which, in turn, is a function of N absorption from the soil and seasonal reallocation of tissue N.

The growth form of bunchgrasses and the environment in which they are found emphasize that N has a strong mediatory role over tiller production which allows the grass plant to respond appropriately to shifts in this limiting resource. This suggests that control of lateral bud outgrowth may have an evolutionary basis in resource competition for N.
Rich calcium availability diminishes heavy metal toxicity in Pied Flycatcher
Authors: EEVA T. , LEHIKOINEN E.
Published: July 2004

Eggshell thickness, egg size, clutch size and egg hatchability of Pied Flycatcher (Ficedula hypoleuca Pallas) are markedly depressed and nestlings show delayed ossification of their leg and wing bones near the copper smelter in Harjavalta, SW Finland. Both defects suggest problems in calcium availability or metabolism. However, another species, the Great Tit (Parus major L.), lays relatively normal eggs and clutches even in the most polluted areas. The Ca content of nestling faeces was measured to estimate between‐species differences in Ca availability.

Parus major nestlings showed four times higher Ca contents in their faeces than F. hypoleuca nestlings, suggesting differential abilities to acquire Ca between the two species.

The availability of Ca‐rich food items was estimated by counting spilled snail shells in the nests of F. hypoleuca postfledging. Snail shells were frequently found except at nests closest to the factory where the amount of exchangeable Ca in organic soil is low and ground layer vegetation is scanty.

The number of snail shells in F. hypoleuca nests correlated positively with the Ca concentration of nestling faeces. Furthermore, snail shell numbers and Ca concentration in faeces were positively associated with breeding success.

There was a significant interaction between Ca and Cu levels of faeces, so that the negative effect of Cu on the number of fledglings was stronger when the Ca level was low, i.e. F. hypoleuca demonstrated poor breeding success especially at territories high in heavy metals and low in snail shells. Our results show that heavy metals have detrimental effects on F. hypoleuca nestlings especially when Ca availability is poor.
Native arbuscular mycorrhizal fungal communities differentially influence the seedling performance of rare and common Pulsatilla species
Authors: MOORA M. , ÖPIK M. , SEN R. , ZOBEL M.
Published: July 2004

An experiment was carried out to determine whether the community composition of root‐colonizing arbuscular mycorrhizal fungi (AMF) influences the growth and nutrient status of two congeneric Pulsatilla species, one rare and one common in Estonia. We hypothesized that: (i) establishment and growth of plants is influenced by the composition of native AMF communities; (ii) growth of congeneric plant species with different abundances differs due to their response to specific AMF communities; and (iii) distribution of a plant species may depend on the composition of local root symbiotic AMF communities.

Rare Pulsatilla patens and common Pulsatilla pratensis were grown in pots, under homogeneous soil nutrient and microbial community conditions, containing either one from two (grassland and forest sites) of natural AMF soil inocula, or no AMF.

Lower establishment was observed in the non‐mycorrhizal soil compared to AMF inoculated soils. Plant biomass, phosphorus concentration and root AMF colonization of both species were higher, and nitrogen concentration lower, in grassland as opposed to forest inoculum.

The common species displayed more vigorous growth than the rare counterpart in the presence of grassland inoculum. Conversely, slightly better growth of a rare species was recorded in the forest inoculum, in which plant biomass was an order of magnitude lower compared to the grassland inoculum.

As Pulsatilla spp. roots hosted site‐characteristic AMF small‐subunit rDNA sequence groupings, we suggest that the presence of AM fungi that are more beneficial for the common species may be one factor behind the observed differential distribution and performance of the two plant species.
Direct measurement of ammonium excretion in soil microarthropods
Authors: SJURSEN H. , HOLMSTRUP M.
Published: July 2004

A simple method for quantifying ammonium excretion in soil microarthropods (Collembola and mites) is described.

Microarthropods were kept in closed vials on a pH‐buffered floor of moist quartz sand where excreted ammonium (NH4‐N) was trapped.

Basic excretion rates in the range of 0·2–1·6 µg ‐N mg−1 dry weight/2 days were estimated for five species of Collembola and one mesostigmatid mite.
Delayed costs of growth and compensatory growth rates
Authors: YEARSLEY J. M. , KYRIAZAKIS I. , GORDON I. J.
Published: July 2004

Many studies recognize that growth carries with it a mortality risk that can influence an animal's growth rate.

Data suggest that these costs of growth act over a range of time‐scales, from instantaneous to an animal's lifetime.

Models of adaptive growth rate have not addressed the issue of differing time‐scales over which the costs of growth act. Here, we develop an adaptive growth model in which the costs of growth are delayed for a period of time, to assess optimal growth strategies in relation to delays in growth costs.

The optimal growth rates are calculated assuming one of two possible fitness measures: the reproductive rate, R0 and the intrinsic population growth rate, r.

It is shown that if the costs of growth are felt only after maturity, then growth compensation can be an adaptive strategy, even in an unchanging environment.

Compensatory growth is predicted only when R0 is the relevant fitness measure, implying that this mechanism of compensatory growth is sensitive to the processes of population regulation.

The effect of time‐delayed costs for other life‐history problems is discussed in light of these results.
Grass populations control nitrification in savanna soils
Authors: LATA J.‐C. , DEGRANGE V. , RAYNAUD X. , MARON P.‐A. , LENSI R. , ABBADIE L.
Published: July 2004

Nitrification plays a key role in the functioning of many natural ecosystems. It is directly involved in plant nitrogen nutrition and soil N losses through leaching and denitrification. The control of this process by plants is poorly understood, although modifications of nitrification would allow plants to manipulate competition for N and induce changes in ecosystem N balance. In a wet tropical savanna ecosystem (Lamto, Côte d’Ivoire), the soil N cycle is characterized by distinct high‐ and low‐nitrification sites. Previous publications showed that nitrification was positively or negatively correlated with root densities of the dominant grass covering these sites. These contrasting sites were chosen to investigate the extent to which vegetation controls long‐term nitrification.

In situexperimental plots were created where grass individuals originating from high‐ or low‐nitrifying soils were transplanted into both soils. Nitrifying enzyme activity (NEA) was measured up to 24 months after transplanting. Grasses from both sites significantly modified NEA up to rates similar to those at their respective control sites.

The level of individual plant control (inhibition and stimulation) was correlated with grass biomass. The potential mechanisms of this control is discussed, along with its consequences for ecosystem N cycling (such as N losses), as the denitrifying enzyme activity (DEA) is much higher in the high‐nitrification site. Such results suggest that plant species can have important consequences for N cycling at the population level.
Nest attentiveness and egg temperature do not explain the variation in incubation periods in tropical birds
Authors: TIELEMAN B. I. , WILLIAMS J. B. , RICKLEFS R. E.
Published: July 2004

The wide range in incubation periods among bird species has puzzled biologists for decades, because an extended egg‐phase increases time‐dependent mortality of the eggs.

We investigated a recently proposed mechanistic explanation inspired by life‐history theory, suggesting that adults may increase their own survival by reducing nest attentiveness, the percentage of daytime spent incubating eggs, in exchange for reduced offspring (egg) survival due to a longer incubation period. Incubation behaviour and egg temperatures (Tegg) of 14 bird species in the humid lowland tropics were studied to test the hypothesis that lower nest attentiveness and reducedTeggcause longer incubation periods.

Increased nest attentiveness correlated with higher averageTegg. However, neither nest attentiveness nor averageTeggwas associated with the length of the incubation period. Longer off‐bouts resulted in lowerTegg, but neither number of off‐bouts nor off‐bout length was associated with incubation period. In addition, we reanalysed a previously published negative association betweenTeggand incubation period based on literature data from temperate passerine birds using a larger data set and found no significant correlation.

In conclusion, our results do not support the hypothesis that longer incubation periods are caused by reduced nest attentiveness and corresponding lowerTegg.
The structure and function of nests of Long‐Tailed Tits Aegithalos caudatus
Authors: McGOWAN A. , SHARP S. P. , HATCHWELL B. J.
Published: July 2004

The aim of this study was to investigate the structure and thermoregulatory function of nests of the Long‐Tailed Tit, Aegithalos caudatus.

The feather lining of Long‐Tailed Tit nests represents a major portion (41%) of the total nest mass.

The mass of feathers varied among nests and declined through the breeding season, but there was no seasonal loss of nest insulation quality because of increasing ambient temperatures.

In an experiment to investigate the seasonal decline in the feather mass of nests, feathers were added to nests at an early stage of the lining phase of nest construction. Nest structure and insulating properties were then examined following nest completion.

The total mass of feathers in treatment and control nests did not differ significantly and there was no significant difference in their nest insulation quality.

Our results demonstrate that Long‐Tailed Tits adjust their nest‐building behaviour according to the nest's thermal environment. Moreover, nest structure appears to be adjusted to prevailing environmental conditions rather than being a function of feather availability or time constraints.
Effects of Racial Diversity on Complex Thinking in College Students
Authors: Antonio Anthony Lising , Chang Mitchell J. , Hakuta Kenji , Kenny David A. , Levin Shana , Milem Jeffrey F.
Published: July 2004

Are experiment varying the racial (Black, White) and opinion composition in small-group discussions was conducted with college students (N = 357) at three universities to test for effects on the perceived novelty of group members' contributions to discussion and on participants' integrative complexity. Results showed that racial and opinion minorities were both perceived as contributing to novelty. Generally positive effects on integrative complexity were found when the groups had racial-and opinion-minority members and when members reported having racially diverse friends and classmates. The findings are discussed in the context of social psychological theories of minority influence and social policy implications for affirmative action. The research supports claims about the educational significance of race in higher education, as well as the complexity of the interaction of racial diversity with contextual and individual factors.
The Correlates and Consequences of Newspaper Reports of Research on Sex Differences
Authors: Brescoll Victoria , LaFrance Marianne
Published: July 2004

Correlates and consequences of newspaper accounts of research on sex differences were examined. In Study 1, articles from high-circulation newspapers were coded for the degree to which biological factors were used to explain sex differences. Results showed that political conservatism and traditional attitudes toward gender roles coded from other newspaper sections predicted greater use of biological explanations than did political liberalism and less traditional attitudes toward gender roles. In Studies 2 and 3, participants read a fictional newspaper article reporting research on a gender difference that cited either biological or sociocultural factors as explaining the difference. Results showed that exposure to biological explanations significantly increased participants' endorsement of gender stereotypes. Moreover, exposure to social explanations significantly increased participants' belief in the mutability of human behavior. Together, these studies show that political ideology influences how the popular press reports research findings and that such reporting in turn affects readers' beliefs and attitudes.
Using and Being Used by Categories
Authors: Robinson Michael D. , Vargas Patrick T. , Tamir Maya , Solberg Emily C.
Published: July 2004

Three studies involving 257 undergraduates examined whether a simple choice reaction time task could predict daily experiences of affect. Individuals who were fast to make negative evaluations experienced more negative affect and more somatic symptoms and were less satisfied with their lives, compared with individuals who were slow to make negative evaluations. A fourth study, involving 89 undergraduates, indicated that performance on the task was relatively unaffected by transitory mood states. The results support the idea that categorization provides a useful perspective on personality functioning.
Is There Any “Free” Choice?
Authors: Kitayama Shinobu , Snibbe Alana Conner , Markus Hazel Rose , Suzuki Tomoko
Published: July 2004

Four experiments provided support for the hypothesis that upon making a choice, individuals justify their choice in order to eliminate doubts about culturally sanctioned aspects of the self, namely, competence and efficacy in North America and positive appraisal by other people in Japan. Japanese participants justified their choice (by increasing liking for chosen items and decreasing liking for rejected items) in the standard free-choice dissonance paradigm only when self-relevant others were primed, either by questionnaires (Studies 1–3) or by incidental exposure to schematic faces (Study 4). In the absence of these social cues, Japanese participants showed no dissonance effect. In contrast, European Americans justified their choices regardless of the social-cue manipulations. Implications for cognitive dissonance theory are discussed.
Thinking About Low-Probability Events
Authors: Koehler Jonathan J. , Macchi Laura
Published: July 2004

The way people respond to the chance that an unlikely event will occur depends on how the event is described. We propose that people attach more weight to unlikely events when they can easily generate or imagine examples in which the event has occurred or will occur than when they cannot. We tested this idea in two experiments with mock jurors using written murder scenarios. The results suggested that jurors attach more weight to the defendant's claim that an incriminating DNA match is merely coincidental when it is easy for them to imagine other individuals whose DNA would also match than when it is not easy for them to imagine such individuals. We manipulated the difficulty of imagining such examples by varying the description of the DNA-match statistic. Some of the variations that influenced the jurors were normatively irrelevant.
Perception of Three-Dimensional Shape From Specular Highlights, Deformations of Shading, and Other Types of Visual Information
Authors: Norman J. Farley , Todd James T. , Orban Guy A.
Published: July 2004

There have been numerous computational models developed in an effort to explain how the human visual system analyzes three-dimensional (3D) surface shape from patterns of image shading, but they all share some important limitations. Models that are applicable to individual static images cannot correctly interpret regions that contain specular highlights, and those that are applicable to moving images have difficulties when a surface moves relative to its sources of illumination. Here we describe a psychophysical experiment that measured the sensitivity of human observers to small differences of 3D shape over a wide variety of conditions. The results provide clear evidence that the presence of specular highlights or the motions of a surface relative to its light source do not pose an impediment to perception, but rather, provide powerful sources of information for the perceptual analysis of 3D shape.
Distribution and prevalence ofWolbachiain Japanese populations of Lepidoptera
Authors: Tagami Y. , Miura K.
Published: July 2004

Wolbachiaare cytoplasmically inherited bacteria that are reported to infect at least 18–30% of all insect species. Our survey of Lepidoptera indicated that 44.9% of forty‐nine species and 77.8% of nine families tested positive forWolbachiausing PCR withwspprimers. Nineteen species had not been described previously as infected. In particular, althoughPieris rapae, which is a common species in Japan, is infected byWolbachia, the prevalence was very low (3.4%) and there were some localities whereWolbachiacould not be detected. The probability of detection ofWolbachiadepends on the number of screened individuals ofP. rapae. The results indicate that the actual number of species that are positive forWolbachiamay be higher than previously reported.
Stress and transcriptional regulation of tick ferritin HC
Authors: Mulenga A. , Simser J. A. , Macaluso K. R. , Azad A. F.
Published: July 2004

We previously identified a partial Dermacentor variabilis cDNA encoding ferritin HC (HC) subunit homolog (DVFER) that was differentially upregulated in Rickettsia montanensis infected ticks (Mulenga et al., 2003a). We have used rapid amplification of cDNA ends to clone full‐length DVFER cDNA and its apparent ortholog from the wood tick, D. andersoni (DAFER), both of which show high sequence similarity to vertebrate than insect ferritin. Both DVFER and DAFER contain the stem–loop structure of a putative iron responsive element in the 5′ untranslated region (nucleotide positions, 16–42) and the feroxidase centre loop typical for vertebrate ferritin HC subunits. Quantitative Western and Northern blotting analyses of protein and RNA from unfed and partially fed whole tick as well as dissected tick tissues demonstrated that DVFER is constitutively and ubiquitously expressed. Based on densitometric analysis of detected protein and mRNA bands, DVFER is predominantly expressed in the midgut, and to a lesser extent in the salivary glands, ovary and fatbody. Sham treatment (mechanical injury) and Escherichia coli challenge of D. variabilis ticks stimulated statistically significant (≈ 1.5‐ and ≈ 3.0‐fold, respectively) increases in DVFER mRNA abundance over time point matched naive control ticks. These data suggest that DVFER mRNA is nonspecifically up regulated in response to mechanical injury or bacterial infection induced stress.
Trends in mortality rates for death‐certificate‐coded diabetes mellitus in an English population 1979–99
Authors: Goldacre M. J. , Duncan M. E. , Cook‐Mozaffari P. , Neil H. A. W.
Published: July 2004

Aims  Mortality statistics have customarily been coded and analysed using only one underlying cause of death. Rules for selecting the underlying cause, when more than one cause is certified on a death certificate, have changed twice in England over the past 20 years. We used data from death certificates for 1979–99 to compare mortality rates for diabetes mellitus certified anywhere on death certificates with those certified as the underlying cause.

Methods  Analysis of data from 18 917 death certificates that included diabetes mellitus in the former Oxford health region.

Results  Based on the underlying cause of death, mortality rates for diabetes varied substantially between the periods defined by rule changes. Based on mentions of diabetes anywhere on the death record, mortality rates were almost unchanged over time: they showed a non‐significant rise of 0.1% per year (95% confidence interval −0.3, 0.6). Circulatory diseases were certified causes of death in 71% of all deaths in people with diabetes. Although mortality rates from circulatory diseases in the general population fell by 2.5% per year, rates for circulatory diseases in combination with diabetes did not fall.

Conclusions  Two explanations are possible for the lack of change in mortality rates for diabetes based on all certified mentions between 1979 and 1999. Increasing prevalence and improved survival may have resulted in no net change; and/or there may have been no improvement in survival for people whose diabetes is associated with life‐threatening pathology and in particular with circulatory diseases.
Transforming growth factor β1 at clinical onset of Type 1 diabetes mellitus. A pilot study
Authors: Flores L. , Näf S. , Hernáez R. , Conget I. , Gomis R. , Esmatjes E.
Published: July 2004

Aims  The aims of the study were to determine whether transforming growth factor β1 TGF‐β1 levels are raised at diagnosis of Type 1 diabetes mellitus and are related to blood glucose.

Subjects and methods  Fourteen patients (mean age 24.3 ± 4.9 years) admitted to hospital for onset of Type 1 diabetes were studied. On the first day of hospitalization, before insulin therapy, and at 1, 4 and 16 weeks, fasting blood glucose, HbA1c, lipid profile and TGF‐β1 levels and TGF‐β1 levels in 24‐h urine were determined. The control group included 14 non‐diabetic subjects with similar characteristics to those of the diabetic group.

Results  Plasma and urinary TGF‐β1 levels were significantly lower in controls (4.7 (1.6–6.8) ng/ml P < 0.001; 5.7 (1.5–8.5) ng/mg urinary creatinine, P < 0.01) than in patients with Type 1 diabetes mellitus [10.5 (1.8–24.9) ng/ml; 10.1 (4.2–29.8) ng/mg urinary creatinine]. On study completion, HbA1c fell from 11.6 ± 2.0 to 5.4 ± 0.6% (P < 0.001). Improved metabolic control was not associated with changes in plasma (9.4 (2.6–19.5)/5.9 (1.6–21.5)/7.0 (2.3–30.2)/10.5 (1.8–24.9) ng/ml at baseline, 1, 4 and 16 weeks, respectively) or urinary (12.0 (4.7–29.5)/10.9 (1.5–20.5)/8.7 (4.3–16.9)/10.1 (4.2–29.8) ng/mg urinary creatinine) TGF‐β1 levels. A statistically significant correlation was observed between plasma TGF‐β1 and insulin dosage (U/kg/day) (r = 0.52, P = 0.037).

Conclusions  The increased TGF‐β1 production observed herein was not modulated by glycaemic reduction and could be a response to immuno‐inflammatory activation present at the onset of Type 1 diabetes.
The metabolic syndrome and coronary heart disease in older women: findings from the British Women's Heart and Health Study
Authors: Lawlor D. A. , Ebrahim S. , Davey Smith G.
Published: July 2004

Aims  To compare two proposed definitions of the metabolic syndrome and to determine the clinical importance of the syndrome with respect to its association with coronary heart disease (CHD).

Methods  Cross‐sectional study of 3770 women aged 60–79 years randomly selected from 23 British towns.

Results  The prevalence of the metabolic syndrome was high in this population and similar with both definitions: 28.2% (95% confidence interval 26.8, 29.7%) of the women had metabolic syndrome according to a modified version of the WHO definition, and 29.2% (27.7, 30.7%) had the ATP III‐defined syndrome. There was reasonable agreement between the two definitions, with 79% of the participants being similarly classified by both definitions. The syndrome was associated with prevalent CHD, with the magnitude of the association with CHD being similar for both definitions. The odds ratio (95% confidence interval) for the age, smoking, physical activity, adult and childhood social class adjusted association of the WHO defined syndrome with prevalent CHD was 1.45 (1.19, 1.75) and for the ATP III‐defined syndrome was 1.53 (1.27, 1.85). Insulin resistance alone, hypertension alone and dyslipidaemia alone were all associated with CHD, with the magnitudes of these associations being similar to those for the WHO and ATP III‐defined syndrome with CHD.

Conclusions  The prevalence of the metabolic syndrome is high in older British women and is associated with CHD. There is reasonable agreement between a modified version of the WHO definition and the ATP III definition of the syndrome, and both are similarly associated with CHD. Single components of the syndrome are associated with CHD to a similar magnitude as the syndrome.
Sex‐differences in prevalence of electrocardiographic left ventricular hypertrophy in Type 2 diabetes: The Casale Monferrato Study
Authors: Bruno G. , Giunti S. , Bargero G. , Ferrero S. , Pagano G. , Perin P. Cavallo
Published: July 2004

Aims  Although left ventricular hypertrophy (LVH) defined by either standard 12‐lead ECG or echocardiography strongly predicts cardiovascular mortality, its prevalence in Type 2 diabetes is largely unknown. We have assessed prevalence of ECG‐LVH and its relationship with clinical and metabolic variables in an Italian population‐based cohort of subjects with Type 2 diabetes.

Methods  The study‐base was 965 (61.3%) subjects with Type 2 diabetes of the population‐based cohort living in Casale Monferrato (Italy). LVH was defined by ECG Cornell voltage‐duration product. All measurements were centralized.

Results  ECG‐LVH was diagnosed in 165/965 subjects, giving a prevalence of 17.1% (95% CI 14.7–19.5). Large sex differences were found, with higher prevalence in women (23.5%, 19.9–27.0) than in men (8.4%, 5.6–11.0), even after adjustment for age, BMI and hypertension (OR 3.83, 95% CI 2.5–5.9). At the examination, subjects with ECG‐LVH were older than those without it. Similar age‐ and sex‐adjusted values of HbA1c, plasma lipids, fibrinogen, uric acid and creatinine were found in the two subgroups. No differences in prevalence of hypertension, CHD, increased QT duration or dispersion, micro‐ and macro‐albuminuria were found between subjects with ECG‐LVH and those without it. In logistic regression analysis, variables independently associated with ECG‐LVH, after age‐adjustment, were sex and diastolic blood pressure.

Conclusions  This population‐based study shows: (i) a high prevalence of ECG‐LVH in Type 2 diabetic subjects; (ii) 3‐fold higher risk in women than in men, independently of age, BMI, and blood pressure; (iii) an independent association between ECG‐LVH and diastolic blood‐pressure. Screening for ECG‐LVH in diabetic subjects is therefore recommended, particularly in diabetic women.
Evaluating risk factors associated with severe hypoglycaemia in epidemiology studies—what method should we use?
Authors: Bulsara M. K. , Holman C. D. J. , Davis E. A. , Jones T. W.
Published: July 2004

Aims  To determine the most appropriate regression models to use when assessing risk factors for severe hypoglycaemia and to investigate the impact of model misspecification and its clinical implications.

Methods  A total of 1229 children with Type 1 diabetes (mean age 11.7 years sd 4.1), of which 605 (49.2%) were males, were studied. Prospective assessment of severe hypoglycaemia (an event leading to loss of consciousness or seizure) was made over the 9‐year period, 1992–2001. Patients were seen every 3 months and episodes of hypoglycaemia along with clinical data were recorded. Over 70% of children never experienced a severe hypoglycaemic event. Data were analysed using the Poisson regression, negative binomial, zero‐inflated Poisson (ZIP) and zero‐inflated negative binomial (ZINB) models. The over‐dispersion and likelihood ratio statistics were calculated and the analytical methods compared.

Results  The Poisson regression model did not fit the data well. The negative binomial and the zero inflated Poisson and negative binomial models fitted the data better than Poisson.

Conclusions  The commonly used Poisson regression models to analyse hypoglycaemia epidemiology may lead to biased parameter estimates and incorrect determination of risk factors for hypoglycaemia. We recommend the use of the negative binomial or zero inflated models to examine any risk factors associated with severe hypoglycaemia. Careful consideration must be given to the interpretation of hypoglycaemia surveys and their analysis.
A 14‐year prospective study of autonomic nerve function in Type 1 diabetic patients: association with nephropathy
Authors: Forsén A. , Kangro M. , Sterner G. , Norrgren K. , Thorsson O. , Wollmer P. , Sundkvist G.
Published: July 2004

Aims  Prospective studies of autonomic nerve function are rare. We have followed the progression of autonomic dysfunction in relation to nephropathy over 14 years in Type 1 diabetic patients.

Methods  Autonomic nerve function was assessed by heart‐rate responses to deep breathing (E/I ratio) and tilting (acceleration and brake indices) and by the postural blood pressure reaction in 58 patients, 43 of whom were reassessed after 14 years. Nephropathy was evaluated by the degree of albuminuria (albuminuria > 20 µg/min or > 0.03 g/24 h) and glomerular filtration rate (51Cr‐EDTA plasma clearance). The acceleration index had deteriorated after 7 years (P = 0.0155), whereas the E/I ratio (P = 0.0070) and the diastolic postural blood pressure reaction (P = 0.0054) had deteriorated 14 years after the baseline examination (age‐corrected values). All those with albuminuria at the third examination showed signs of autonomic neuropathy at baseline (10 of 10) compared with only nine of 22 without (P = 0.0016). Multiple regression analysis showed that the association between autonomic dysfunction and future albuminuria was due to the E/I ratio. In addition, individuals with an abnormal postural diastolic blood pressure fall (n = 7) at baseline showed a greater fall in glomerular filtration rate more than others 7–14 years later [29 (16.5) ml/min/1.72 m2 vs. 11 (9) ml/min/1.72 m2; P = 0.0074].

Conclusion  Autonomic nerve function had deteriorated after 14 years. Autonomic neuropathy and abnormal postural diastolic blood pressure falls at baseline were associated with future renal complications.
Association of aldose reductase gene Z+2 polymorphism with reduced susceptibility to diabetic nephropathy in Caucasian Type 1 diabetic patients
Authors: Lajer M. , Tarnow L. , Fleckner J. , Hansen B. V. , Edwards D. G. , Parving H‐H. , Boel E.
Published: July 2004

Aims  The Z−2 allele of the (AC)n polymorphism in the aldose reductase gene (ALR2) confers increased risk of microvascular diabetic complications, whereas the Z+2 allele has been proposed to be a marker of protection. However data are conflicting. Therefore, we investigated whether this polymorphism is associated with diabetic nephropathy and retinopathy in Type 1 diabetes mellitus in a large case–control study and a family‐based analysis.

Methods  A total of 431 Type 1 diabetic patients with diabetic nephropathy and 468 patients with longstanding Type 1 diabetes and persistent normoalbuminuria were genotyped for the case–control study. In addition, 102 case trios and 98 control trios were genotyped for a family‐based study.

Results  Thirteen different alleles were identified. In the case–control study, the Z+2 allele frequency was significantly higher in the normoalbuminuric diabetic than in patients with diabetic nephropathy (0.17 vs. 0.11, P = 0.008), suggesting a protective function of the Z+2 allele. No significant increase in the frequency of the putative risk allele Z−2 was found in patients with diabetic nephropathy vs. controls (0.39 vs. 0.36). No association with diabetic retinopathy was found. Although the results of the transmission of the Z−2 and Z+2 alleles in the independent family‐based study were consistent with the association study, the number of informative families was limited and thus differences were not statistically significant.

Conclusions  The Z+2 allele of the ALR2 promoter polymorphism is associated with a reduced susceptibility to diabetic nephropathy in Danish Type 1 diabetic patients, suggesting a minor role for the polyol pathway in the pathogenesis of diabetic kidney disease. No association of the ALR2 polymorphism with diabetic retinopathy was found.
Thiazolidinediones and congestive heart failure—exacerbation or new onset of left ventricular dysfunction?
Authors: Srivastava P. M. , Calafiore P. , MacIsaac R. J. , Hare D. L. , Jerums G. , Burrell L. M.
Published: July 2004

Background  Patients with diabetes mellitus have a high incidence of coronary heart disease and congestive heart failure (CHF). Thiazolidinediones (TZD) are a new class of pharmacological agents for the treatment of Type 2 diabetes mellitus, which have many beneficial cardiovascular effects. Peripheral oedema and weight gain have been reported in 4.8% of subjects on TZDs alone, with a higher incidence noted in those receiving combination insulin therapy (up to 15%), but there is limited data on the occurrence of CHF.

Methods and results  In this paper, we report on six cases of TZD‐induced fluid retention with symptoms and signs of peripheral oedema and/or CHF that occurred in subjects attending our diabetic clinic. The predominant finding in all cases was of diastolic dysfunction. All subjects were obese and hypertensive, with 5/6 having the additional risk factor of LVH, 5/6 subjects had microvascular complications, whilst 3/6 were also on insulin therapy.

Conclusion  We suggest that obese, hypertensive diabetics may benefit from echocardiographic screening prior to commencement of TZDs, as these agents may exacerbate underlying undiagnosed left ventricular diastolic dysfunction.
Peer Victimization: The Role of Emotions in Adaptive and Maladaptive Coping
Authors: Kochenderfer‐Ladd Becky
Published: July 2004

Mediator models were examined in which children's emotional reactions to peer aggression were hypothesized to mediate their selection of coping strategies and subsequent peer victimization and internalizing problems. Self‐report data were collected from 145 ethnically diverse kindergarten through fifth grade children (66 females and 79 males) who attended a predominantly low‐ to middle‐class school. Hypothetical scenarios were used to assess children's anticipated responses to peer aggression. Victims reported more intense negative emotions (e.g., fear and anger) than did nonvictims. Fear emerged as a predictor of advice seeking which, in turn, predicted conflict resolution and fewer internalizing problems. Conflict resolution was associated with reductions in victimization. Anger and embarrassment predicted revenge seeking which, in turn, was associated with increases in victimization. Additional pathways predicting changes in peer victimization across a single academic year as a function of children's emotional and coping responses to peer abuse are discussed.
The Social Cognitions of Socially Withdrawn Children
Authors: Wichmann Cherami , Coplan Robert J. , Daniels Tina
Published: July 2004

The purpose of this study was to examine the social cognitions of peer‐identified socially withdrawn children. Participants included 457 children from grades four, five and six (54% females, 46% males). Children completed a selection of self‐ and peer‐report measures including: (1) peer‐rated behavioral nominations; (2) hostile intent biases and social responses to ambiguous situations; (3) social goals and self‐efficacy; and (4) a newly developed measure of causal attributions. An extreme groups procedure was used to identify three groups of children: (1) socially withdrawn (n=50); (2) aggressive (n=53); and (3) a comparison group (n=206). As compared with their peers, withdrawn children displayed a pattern of self‐defeating attributions for social situations, reported lower efficacy for assertive goals, and indicated a preference for non‐assertive, withdrawn strategies to deal with hypothetical conflict situations. Findings are discussed with respect to implications for interventions, and directions for further research are presented.
Methods for the analysis of bleeding outcomes in randomized trials of PLT transfusion triggers
Authors: Cook R.J. , Heddle N.M. , Rebulla P. , Sigouin C.S. , Webert K.E. ,   the Biomedical Excellence for Safer Transfusion (BEST) Working Party of the International Society for Blood Transfusion
Published: July 2004

BACKGROUND:  A number of methodologic challenges arise in the analysis of bleeding data from clinical trials of PLT transfusion triggers. It is important to understand the assumptions and role of the various methods of analysis to interpret published trials and to design future studies appropriately.

STUDY DESIGN AND METHODS:  The methods of analysis used for testing the effectiveness and safety of transfusion strategies are reviewed from several recent PLT transfusion trigger trials. The underlying assumptions of these methods are discussed, as well as the clinical interpretations of the resulting summary statistics. Four methods of analysis were applied to data from a large PLT transfusion trigger study to illustrate the differences in the interpretations that can arise from various approaches.

RESULTS:  PLT transfusion trigger trials of patients with leukemia have based their primary analyses on 1) simple dichotomous classifications of whether or not at least 1 day of clinically important bleeding was experienced; 2) the time to the first day of clinically important bleeding; and 3) the proportion of days at risk with clinically important bleeding. Recurrent event methods provide a robust alternative approach to the analysis of this kind of data and should be considered if interest is in capturing the overall burden of bleeding over time. These four methods differ in the extent to which they utilize information on the number of days with bleeding and the temporal variation in bleeding patterns. Inferences drawn regarding the relative safety and efficacy of different transfusion triggers can vary depending on the method of analysis.

CONCLUSION:  To rigorously design and analyze future PLT transfusion studies based on bleeding outcomes, it is important to have a clear understanding of the interpretation of the different ways of analyzing bleeding outcomes. The analysis strategy should be selected based on the clinical question being addressed.
Platelet transfusions during coronary artery bypass graft surgery are associated with serious adverse outcomes
Authors: Spiess Bruce D. , Royston David , Levy Jerrold H. , Fitch Jane , Dietrich Wulf , Body Simon , Murkin John , Nadel Andrea
Published: July 2004

BACKGROUND:  Platelet (PLT) transfusions are administered in cardiac surgery to prevent or treat bleeding, despite appreciation of the risks of blood component transfusion. The current analysis investigates the hypothesis that PLT transfusion is associated with adverse outcomes associated with coronary artery bypass graft surgery (CABG).

STUDY DESIGN AND METHODS:  Data originally collected during double‐blind placebo‐controlled phase III trials for licensure of Trasylol (aprotinin injection) were retrospectively analyzed. Adverse outcome data of patients (n = 1720) that received, and did not receive, perioperative PLT transfusion were compared. Logistic regression analysis was used to assess the association of perioperative adverse events with PLT transfusion. Propensity scoring analysis was used to verify results of the logistic regression.

RESULTS:  Patients receiving PLTs were more likely to have prolonged hospital stays, longer surgeries, more bleeding, re‐operation for bleeding, and more RBC transfusions, and less likely to have full‐dose aprotinin administration. Adverse events were statistically more frequent in patients that received one or more PLT transfusion. Logistic regression analysis showed that PLT transfusion was associated with infection, vasopressor use, respiratory medication use, stroke, and death. Propensity scoring analysis confirmed the risk of PLT transfusion.

CONCLUSIONS:  PLT transfusion in the perioperative period of CABG was associated with increased risk for serious adverse events. PLT transfusion may be a surrogate marker for sicker patients and have no causal role in the outcomes observed. However, a direct contribution to outcomes remains possible.
Validation and assessment of a blood‐donor arm disinfectant containing chlorhexidine and alcohol
Authors: Wong P.‐Y. , Colville V.L. , White V. , Walker H.M. , Morris R.A. ,   The Microbial Contamination and Infection Control Subcommittee, Australian Red Cross Blood Service
Published: July 2004

BACKGROUND:  To minimize the bacterial contamination rate in blood collected from donors, a study was designed to evaluate the suitability of a single‐use chlorhexidine‐alcohol antiseptic for donor arm preparation at all blood collection venues in Australia.

STUDY DESIGN AND METHODS:  A prospective study of bacterial load on the skin was performed on 616 blood donors’ arms before and after disinfection using a direct swabbing and plating technique. Disinfection was achieved with a swab containing 1 percent chlorhexidine gluconate with 75 percent alcohol, which was applied to the skin in a prescribed method. Feedback from blood donors and staff was obtained using questionnaires.

RESULTS:  After disinfection, 99 percent of donor arms had bacterial counts of 5 cfu per plate or less, and 99.5 percent had counts of 10 cfu per plate or less, respectively. The mean colony count for all donors after disinfection was 0.39, and the percentage reduction was 99 compared to predisinfection. Sixteen donors (3%) noted transient skin irritation. The majority of staff (64%) preferred not to use the new disinfectant due to the difficulty opening the packaging and an excessive amount of antiseptic solution per pack.

CONCLUSION:  The bacteriologic study showed that the disinfectant satisfied the requirements of the Australian Red Cross Blood Service for use to prepare blood‐donor arms before venesection. An improvement to the packaging was required before it could be acceptable to all staff.
Storage of platelets in additive solution for up to 12 days with maintenance of good in‐vitro quality
Authors: Van Der Meer Pieter F. , Pietersz Ruby N.I. , Reesink Henk W.
Published: July 2004

BACKGROUND:  Storage of PLT concentrates (PCs) may be extended beyond 5 days, provided in‐vitro and in‐vivo variables allow longer storage and bacterial screening is performed. The aim of this study was to examine in‐vitro storage characteristics of PCs in various storage solutions: plasma only, or mixtures of plasma with PAS‐II, PAS‐III, PAS‐IIIM, and Composol.

STUDY DESIGN AND METHODS:  PCs from five pooled buffy‐coats and WBCs reduced by filtration were stored in 1.3‐L butyryl‐tri‐hexyl‐citrate‐plasticised PVC containers. First, a paired comparison was made between PAS‐II and Composol, with 35‐percent final plasma concentration (n = 10). Then, plasma, PAS‐III with 30‐percent plasma, PAS‐IIIM with 20‐ and 30‐percent plasma, and Composol with 20 and 30‐percent final plasma concentration were compared (n = 5 pairs). Finally, 50 PCs in Composol with 35‐percent final plasma concentration were studied.

RESULTS:  PCs in PAS‐II or Composol had a mean ± SD pH of 6.95 ± 0.09 and 6.96 ± 0.08 at Day 12, respectively. For PCs in PAS‐IIIM and Composol with 30‐percent final plasma concentration, pH on Day 7 was 7.00 ± 0.02 and 6.83 ± 0.05. With 20‐percent final plasma concentration, pH was 6.98 ± 0.02 and 6.81 ± 0.03 for PAS‐IIIM and Composol, respectively. PCs in PAS‐III with 30‐percent plasma had a pH on Day 7 of 6.87 ± 0.03, whereas PCs in 100‐percent plasma had a pH of 7.05 ± 0.03. PCs in Composol with 35‐percent plasma maintained pH greater than 6.8 in 48 of 50 of the units (96%), averaging 7.00 ± 0.10 on Day 8.

CONCLUSION:  In‐vitro quality of PCs in AS with at least 35‐percent plasma can be maintained for 7 to 12 days after collection.