bluuebunny/crossref_metadata_2025_split huggingface dataset:
Importance of calcium in modifying the acute toxicity of sodium sulphate toHyalella aztecaandDaphnia magna
Authors: Davies Trevor D. , Hall Ken J. 
Published: May 2007

AbstractModification of the acute toxicity of sodium sulphate to Hyalella azteca and Daphnia magna was investigated using exposure water with different levels of water hardness (expressed as CaCO3 equivalents) and calcium–magnesium molar (Ca:Mg) ratios. The influence of Ca:Mg ratios on the toxicity of sodium and potassium chloride to D. magna also was investigated. For both species, the mean lethal concentrations that resulted in mortality of 50% of the sample population (LC50s), expressed as mg SO42–/L, were increased significantly in harder water and in water with higher Ca:Mg ratios. The LC50s for H. azteca increased from 569 to 5,259 mg/L with a change in water hardness from 25 to 250 mg/L. Furthermore, modifying the Ca:Mg ratio from 0.7 to 7.0 at a constant hardness of 100 mg/L significantly increased LC50s from 2,101 to 2,725 mg/L. The LC50s for D. magna were also significantly higher in harder water with LC50s increasing from 1,194 to 3,203 mg/L with a change in water hardness from 25 to 100 mg/L. In addition, modifying the Ca:Mg ratio from 0.7 to 7.0 significantly increased LC50s from 1,194 to 1,985 at a constant hardness of 25 mg/L, and from 3,203 to 4,395 mg/L at a constant hardness of 100 mg/L. No significant change in the toxicity of potassium or sodium chloride to D. magna was observed in waters with higher Ca:Mg ratios.
Influence of organism age on metal toxicity toDaphnia magna
Authors: Hoang Tham C. , Klaine Stephen J. 
Published: May 2007

AbstractAquatic organisms living in surface water experience contaminant exposure at different life stages. While some investigators have examined the influence of organism age on the toxicity of pollutants, the general assumption in toxicology has been that young organisms were more sensitive than older organisms. In fact, some standardized toxicity tests call for the use of organisms less than 24 h old. This research characterized the age sensitivity of the water flea Daphnia magna to copper, zinc, selenium, and arsenic. During 21-d toxicity tests, organisms were exposed to a single 12-h pulse of either 70 μg/L Cu, 750 μg/L Zn, 1,000 μg/L Se, or 5,000 μg/L As at different ages ranging from 3 h to 10 d old. Mortality and reproduction were compiled over 21 d. During the juvenile stage, mortality increased and cumulative reproduction decreased with age, respectively. However, mortality decreased and cumulative reproduction increased with age when organisms became adult. Peak sensitivity occurred in 4-d-old organisms exposed to Cu and Zn, while 2- to 3-d-old organisms were most sensitive to As and Se. Growth of D. magna over 21 d was not affected by the 12-h pulse of Cu, Zn, Se, or As given at any organism age. This indicates the recovery of the organisms after exposure termination.
Response spectrum of pentachlorobenzene and fluoranthene forChironomus tentansandHyalella azteca
Authors: Schuler Lance J. , Landrum Peter F. , Lydy Michael J. 
Published: May 2007

AbstractThe whole-body residues of pentachlorobenzene (PCBz) and fluoranthene (FLU) in Hyalella azteca and Chironomus tentans were determined for a variety of chronic sublethal effects. The endpoints evaluated for H. azteca included 28-d growth and survival and 42-d growth, survival, and reproduction. Adverse effects to C. tentans also were determined at multiple endpoints including 10-d growth, cumulative pupation and emergence, and reproduction. The lowest-observed-effect residue (LOER) based on whole-body residues associated with growth was consistent between compounds and species tested with concentrations ranging from 0.17 to 0.33 μmol/g. For H. azteca, the most sensitive endpoints were growth at 0.23 μmol/g and reproduction at 0.11 μmol/g for PCBz and FLU, respectively. For C. tentans, the most sensitive endpoints were emergence, development and reproduction at 0.02 μmol/g, and development and reproduction at 0.15 μmol/g for PCBz and FLU, respectively. Compared to residues associated with acute lethality, the most sensitive sublethal endpoints were approximately 4 and 60 times lower for PCBz and FLU, respectively. The relative consistency of the sublethal endpoints suggests that body residues can be a valuable tool to evaluate bioaccumulation data as part of a risk assessment to predict adverse effects to biota.
RAGE and its ligands: a lasting memory in diabetic complications?
Authors: Yan Shi-Fang , Ramasamy Ravichandran , Bucciarelli Loredana G , Wendt Thoralf , Lee Larisse K , Hudson Barry I , Stenr David M , Lalla Evanthia , Du Yan Shi , Rong Ling Ling , Naka Yoshifumi , Schmidt Ann Marie 
Published: May 2007

The complications of diabetes are myriad and represent a rising cause of morbidity and mortality, particularly in the Western world. The update of the Diabetes Control and Clinical Trials Group/Epidemiology of Diabetes Interventions and Complications Research Group (DCCT/EDIC) suggested that previous strict control of hyperglycaemia was associated with reduced carotid atherosclerosis compared to conventional treatment, even after levels of glycosylated haemoglobin between the two treatment groups became indistinguishable. These intriguing findings prompt the key question, why does the blood vessel ‘remember’? This review focuses on the hypothesis that the ligand/RAGE axis contributes importantly to glycaemic ‘memory’. Studies in rodent models of diabetes suggest that blockade or genetic modification of RAGE suppress diabetes-associated progression of atherosclerosis, exaggerated neointimal expansion consequent to acute arterial injury, and cardiac dysfunction. We propose that therapeutic RAGE blockade will intercept maladaptive diabetes-associated memory in the vessel wall and provide cardiovascular protection in diabetes.
Pioglitazone plus a sulphonylurea or metformin is associated with increased lipoprotein particle size in patients with type 2 diabetes
Authors: Perez Alfonso , Khan Mehmood , Johnson Todd , Karunaratne Mahinda 
Published: May 2007

Objective To determine the effect of pioglitazone plus metformin or a sulphonylurea on lipoprotein particle size and subclass distribution in patients with type 2 diabetes. Methods Lipid profiles were determined for blood samples from patients participating in two randomised, double-blind, 24-week studies of pioglitazone 30 mg or 45 mg daily plus either metformin or a sulphonylurea. Results Samples from 177 patients were evaluated; 96 of these patients received a sulphonylurea, and 81 received metformin. Pioglitazone combination treatment produced significant increases from baseline for average and peak low-density lipoprotein (LDL) particle size at weeks 12 and 24 (p<0.0001 for each; range 0.29–0.39 nm for average and 0.36–0.55 nm for peak particle size, respectively). Significant shifts in high-density lipoprotein (HDL) and LDL distribution showed an increase in large particles and a decrease in small particles. For pioglitazone plus metformin, significant increases in levels of apolipoprotein (Apo) AI, Apo AI/AII-containing HDL, and lipoprotein(a) also were noted, whereas Apo B levels decreased. Conclusions These observed changes are thought to affect the atherogenic profile positively. Therefore, pioglitazone combination treatment may lead to decreased cardiovascular risk in patients with type 2 diabetes.
Effects of low-dose continuous combined HRT on vascular function in women with type 2 diabetes
Authors: Kernohan Andrew FB , Spiers Angela , Sattar Naveed , Hillier Chris , Cleland Steve J , Small Michael , Lumsden Mary-Ann , Connell John MC , Petrie John R 
Published: May 2007

Background Improvement in vascular endothelial function is widely cited as a beneficial effect of hormone replacement therapy (HRT). Women with type 2 diabetes (T2DM) are at increased cardiovascular risk and have impaired endothelial function. Any benefits of HRT on endothelial function in this group are of particular interest. Objectives We assessed effects on vascular function of oral 17β oestradiol (1 mg) and norethisterone (0.5 mg) in postmenopausal women with T2DM. Design Double-blind, randomised, placebo-controlled trial. Assessments Twenty-eight women had pulse wave velocity (PWV) and adhesion molecules VCAM-1 and ICAM-1 assessed before and after three months' treatment. Twenty-four women also had gluteal fat biopsy for assessment of resistance vessel function (using wire myography). Results HRT did not affect PWV, VCAM-1, ICAM-1 or carbachol response. Effects of L-NAME and indomethacin on carbachol sensitivity were similar in both groups. Conclusions This HRT preparation had no detectable effect on these measures of endothelial function in women with T2DM.
Enhanced left ventricular systolic function early in type 2 diabetic mice: clinical implications
Authors: Alvarez Jorge A , Reyes Maricela , Escobedo Daniel , Freeman Gregory L , Steinhelper Mark E , Feldman Marc D 
Published: May 2007

It is unclear whether the increase in availability of substrates for energy production in diabetes can lead to enhanced systolic function early in the disease, before the onset of structural changes to the myocardium. To examine this issue, BKS. Cg- m +/+ Lepr db (db/db) mice with type 2 diabetes and wild type controls had left ventricular pressure-volume relationships determined in situ. We demonstrated that the db/db mice, when compared to their wild type controls, generated greater left ventricular pressure and an enhancement of left ventricular systolic function based on enhanced power/EDV, positive dP/dt, preload recruitable stroke work, dP/dt — EDV relationship, and curvilinear end-systolic elastance. This enhancement in systolic function occurred despite the db/db mice having greater body weight, but similar preload (end-diastolic volume) and afterload (effective arterial elastance). We postulate that the previously described enhancement in renal glomerular filtration rate seen early in type 2 diabetes may be in part due to enhanced left ventricular systolic function early in this disease.
Metabolic syndrome-mediated inflammation following elective percutaneous coronary intervention
Authors: Marso Steven P , Murphy Joseph W , House John A , Safley David M , Harris William S 
Published: May 2007

There are few data concerning the relationship between diabetes mellitus, the metabolic syndrome and inflammation following elective percutaneous coronary intervention (PCI). The purpose of this study was to assess basal and peak levels of candidate cytokines in 40 patients undergoing elective PCI. Patients were categorised as having diabetes mellitus, the metabolic syndrome, or neither. Patients with the metabolic syndrome exhibited significantly greater levels of tumour necrosis factor-a over the study period, although this was unrelated to PCI. There was a trend for increased levels of interleukin-6 following PCI, primarily among patients with metabolic syndrome. Basal levels of monocyte chemoattractant protein-1 (MCP-1) were not different among study groups; however, the metabolic syndrome cohort had a trend towards increased circulating levels of MCP-1 after PCI. In this patient population, the metabolic syndrome correlates with a heightened inflammatory response following elective PCI.
Impaired glucose tolerance and impaired fasting glucose — a review of diagnosis, clinical implications and management
Authors: Petersen John L , McGuire Darren K 
Published: May 2007

The diagnostic categories of impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) were established in an effort to identify populations at risk for developing type 2 diabetes mellitus (T2DM). Both IGT and IFG are associated with increased risk of developing T2DM, but recent analyses found that the thresholds of risk vary among different populations and an even lower diagnostic threshold of IFG may be appropriate. IGT has been linked with an increased risk of cardiovascular events and some analyses have demonstrated an increased mortality risk compared with patients with normal glucose tolerance. In contrast, a continuum of increased risk of microvascular manifestations of T2DM has been demonstrated with IFG but an association of IFG with cardiovascular events has not been well established. Although both IGT and IFG are associated with resistance to insulin and increased insulin secretion, they do not identify the identical patient populations and are not equivalent in predicting development of T2DM or cardiovascular events. IFG and IGT have been associated with other features of insulin resistance, including dyslipidaemia, hypertension, abdominal obesity, microalbuminuria, endothelial dysfunction, and markers of inflammation and hypercoagulability, traits collectively referred to as the metabolic syndrome. Analyses of combinations of these components have also been associated with progression to T2DM, cardiovascular disease and increased mortality. The foundation of treatment for IGT, IFG, and the metabolic syndrome is lifestyle modification, including both dietary change and routine exercise. To date, several clinical trials have found that lifestyle modification is the most efficacious strategy to prevent progression to T2DM. Alternative treatments include pharmacotherapy with metformin or acarbose, both of which have been demonstrated to decrease the development of T2DM. Ongoing clinical trials are evaluating newer pharmacotherapies, including angiotensin converting enzyme inhibitors, angiotensin receptor antagonists, metglitinides and thiazolidinediones, to prevent both T2DM and cardiovascular events. In combination with lifestyle modification, these therapies offer hope for effective prevention of T2DM and its consequences in high-risk patients.
Cells expressing the stem cell factor receptor, c-kit, contribute to neoangiogenesis in diabetes
Authors: Kelly Darren J , Zhang Yuan , Gow Renae M , Itescu Silviu , Gilbert Richard E 
Published: May 2007

While neoangiogenesis in diabetes is of greatest clinical significance in the retina, the pathological formation of new blood vessels also develops in other vascular beds in diabetes, including the mesentery of the streptozotocin-induced diabetic rat. However, the contribution of bone marrow-derived cells to this process of vasculogenesis is unknown. In this study, male Sprague-Dawley rats were randomised to receive either streptozotocin or vehicle, and their mesenteric vasculature was examined after three weeks. Origins from bone marrow and endothelial cell differentiation were identified by immunolabelling for the stem cell factor receptor, c-kit and von Willebrand factor (vWF), respectively. Expression for the angiogenic chemokine, stromal derived factor-1 (SDF-1) was assessed by quantitative real-time polymerase chain reaction (PCR). At three weeks, rats with diabetes had a dramatic (190-fold) increase in lectin-labelled blood vessel profiles in the mesenteric bed (p<0.0001) in association with a five-fold increase in SDF-1 mRNA (p<0.01). Immunohistochemical studies identified abundant large, ovoid, lumen-forming, c-kit+ cells in the mesentery of diabetic, but not control, rats. Many of these c-kit+ cells also showed positive immunolabelling for vWF, consistent with endothelial differentiation. In conclusion, cells of bone marrow origin contribute to new vessel formation in the diabetic mesentery. This phenomenon may also apply to the neovascularisation that develops at clinically important sites such as in the retina.
Effects of improved metabolic control on platelet reactivity in patients with type 2 diabetes mellitus following coronary angioplasty
Authors: Yngen Marianne , Norhammar Anna , Hjemdahl Paul , Wallén N Håkan 
Published: May 2007

The aim of this study was to investigate the impact of improved metabolic control on platelet reactivity in patients with type 2 diabetes undergoing percutaneous coronary intervention (PCI). Twenty-two patients were randomised to intensive insulin or conventional treatment for diabetes. Platelet P-selectin expression was analysed before and three months after PCI. Metabolic control, as measured by level of glycosylated haemoglobin (HbA1C) and platelet P-selectin expression, was similar in the two treatment groups after three months. However, six of the 12 patients in the intensive group had increased levels of HbA1C after three months and three patients of the 10 in the conventionally treated group showed improved metabolic control. A re-analysis was performed, based on metabolic control. It showed that patients with improved control at three months (HbA1C 6.1% ± 0.7 at baseline; 5.7% ± 0.5 at three months; p<0.01; n=9) had lower ADP-induced P-selectin expression (p<0.05) than patients with worsened glycaemic control (HbA1C 5.9% ± 1.0 at baseline; 6.5% ± 1.4 at three months; p<0.01; n=13). Levels of HbA1C and fasting glucose were correlated to P-selectin expression (R=0.34 and R=0.31; p<0.05). We conclude from this study that improved glycaemic control reduces platelet reactivity in type 2 diabetes patients following PCI.
Thrifty genes for obesity and the metabolic syndrome — time to call off the search?
Authors: Speakman John R 
Published: May 2007

Over the last 50 years there has been a major epidemic of obesity and associated co-morbidities, the so-called ‘metabolic syndrome’, mostly in the western world but with an increasingly global dimension. The development of such chronic diseases has a strong genetic component, yet the timescale of their increase cannot reflect a population genetic change. Consequently, the most accepted model is that obesity and its sequelae are a result of a gene-environment interaction, an ancient genetic selection to deposit fat efficiently that is maladaptive in modern society. Why we have this genetic predisposition has been a matter of much speculation. Following the seminal contribution of Neel, 1 there has been a broad consensus that over evolutionary time we have been exposed to regular periods of famine, during which fatter individuals would have enjoyed a selective advantage by their greater survival. Consequently, individuals with genes promoting the efficient deposition of fat during periods between famines (‘thrifty genes’) would be favoured. In the modern environment this genetic predisposition prepares us for a famine that never comes, and an epidemic of obesity with all the attendant chronic illnesses follows. In this review I present details of the evidence supporting the famine hypothesis and then show that this idea has five fundamental flaws. In essence, famines are a relatively modern phenomenon and occur only about once every 100–150 years. Consequently, most human populations have only experienced at most 100 famine events in their evolutionary history. Famines involve increases in total mortality that only rarely exceed 10% of the population. Moreover, most people in famines die of disease rather than starvation and the age distribution of mortality during famine would not result in differential mortality between lean and obese individuals. A simple genetic model shows that famines provide insufficient selective advantage over an insufficient time period for a thrifty gene to have any penetration in the modern human population. Over the 40 or so years since Neel proposed the thrifty gene hypothesis, no convincing candidates for these genes have been discovered. My analysis suggests that perhaps it is time to call off the search.
A multinational assessment of complications in type 1 diabetes: the DiaMond substudy of complications (DiaComp) Level 1
Authors: Walsh Michael G , Zgibor Janice , Borch-Johnsen Knut , Orchard Trevor J 
Published: May 2007

The objectives of this study were to describe the global geographic variation of microvascular and macrovascular complications in childhood onset type 1 diabetes (T1D) and to relate any such variation to diabetes care activities such as self blood glucose monitoring and intensive insulin therapy. The DiaComp study is a multinational (17 countries) cross-sectional study of complications in T1D (n=2, 657). All participants were diagnosed at < 15 years of age and had a diabetes duration of 5-24 years when surveyed. Complications were assessed by self-report of physician diagnosis. Twenty-two centres in 17 countries achieved at least a 67% response rate and are included in the analyses. Central European centres exhibited high rates of retinopathy (Lithuania=31. 6%, Romania=24. 2%), laser treatment (Lithuania=25. 4%) and neuropathy (Lithuania=29. 9%, Romania=12. 4%) in those with short duration of diabetes (5–15 years), as did Cuba for neuropathy (15. 4%). For retinopathy the geographic variation in the short-duration group was also pronounced, ranging from 1. 6% in Italy to 41. 6% in Lithuania, and from 0% in Brazil, Italy and Australia, to 29. 9% in Lithuania for laser treatment. Variation was less dramatic for the prevalence of complications in the long-duration group (15–25 years). Hypertension and duration were strong consistent predictors of all complications, while women had higher prevalence for half the complications (retinopathy, laser treatment and renal disease). Intensive insulin therapy and self-monitoring of blood glucose showed little association with prevalence of complications. In conclusion, this first population-based account of the geographic variation of T1D complications has demonstrated substantial variation. However, the healthcare practice variables that were measured contributed little toward explaining this variation.
Baseline characteristics of the randomised cohort from the Look AHEAD (Action for Health in Diabetes) study
Authors: Bray George A. 
Published: May 2007

Objective. The Look AHEAD (Action for Health in Diabetes) study is a 16-centre randomised clinical trial in overweight and obese individuals with type 2 diabetes, designed to evaluate the long-term effects (up to 11.5 years) of intensive weight loss intervention on the time to incidence of major cardiovascular events. Research design and methods. Eligibility requirements are diagnosis of type 2 diabetes (determined by self-report and verification) in individuals aged 45-74 years and body mass index (BMI) > 25 kg/m2 (> 27 kg/m2 if currently taking insulin). The intensive lifestyle intervention is designed to achieve and maintain weight loss through decreased caloric intake and increased physical activity. The study is designed to provide 90% probability of detecting an 18% difference in major cardiovascular disease event rates in patients randomised to the intensive lifestyle intervention compared to the control group receiving standard diabetes support and education. Results. The 5, 145 participants who were randomised between 2001 and 2004 were 63.3% white, 15.6% African-American, 13.2% Hispanic, 5.0% American Indian and 1.0% Asian-American, which closely paralleled the ethnic distribution of diabetes in the National Health and Nutrition Examination Survey (NHANES) 1999-2000 survey. Their average age at entry was 59± 6.8 years (mean ± SD), and 60% were women. There were 31.5% between 45-55 years of age, 51.5% were 56-65, and 17.0% were 66-76 years of age. Some 15.4% of participants were taking insulin at the time of randomisation and 14.0% had a history of cardiovascular disease. More men (21.3%) than women (9.2%) had a history of cardiovascular disease. Few participants (4.4%) were current cigarette smokers, compared to 16.2% in the NHANES 1999-2000 survey. Furthermore, 65.0% of participants had a first-degree relative with diabetes. Overall, BMI averaged 36±5.9 kg/m2 at baseline, with 83.6% of the men and 86.1% of women having a BMI > 30 kg/m2 and 17.9% of men and 25.4% of women having a BMI > 40 kg/m2 Conclusions. The Look AHEAD study has successfully randomised a large cohort of participants who have type 2 diabetes with a wide distribution of age, obesity, ethnicity and racial background and will examine the effects of lifestyle intervention on the incidence of major cardiovascular events.