bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of the Dipeptidyl Peptidase-IV Inhibitor Vildagliptin on Incretin Hormones, Islet Function, and Postprandial Glycemia in Subjects With Impaired Glucose Tolerance
Authors: Rosenstock Julio , Foley James E. , Rendell Marc , Landin-Olsson Mona , Holst Jens J. , Deacon Carolyn F. , Rochotte Erika , Baron Michelle A. 
Published: December 2007

OBJECTIVE—This study was conducted to determine the effects of vildagliptin on incretin hormone levels, islet function, and postprandial glucose control in subjects with impaired glucose tolerance (IGT).
RESEARCH DESIGN AND METHODS—A 12-week, double-blind, randomized, parallel-group study comparing vildagliptin (50 mg q.d.) and placebo was conducted in 179 subjects with IGT (2-h glucose 9.1 mmol/l, A1C 5.9%). Plasma levels of intact glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP), glucose, insulin, C-peptide, and glucagon were measured during standard meal tests performed at baseline and at week 12. Insulin secretory rate (ISR) was estimated by C-peptide deconvolution. The between-group differences (vildagliptin − placebo) in the adjusted mean changes from baseline to end point in the total and incremental (Δ) area under the curve (AUC)0–2 h for these analytes were assessed by ANCOVA; glucose AUC0–2 h was the primary outcome variable.
RESULTS—Relative to placebo, vildagliptin increased GLP-1 (ΔAUC, +6.0 ± 1.2 pmol · l−1 · h−1, P &lt; 0.001) and GIP (ΔAUC, +46.8 ± 5.4 pmol · l−1 · h−1, P &lt; 0.001) and decreased glucagon (ΔAUC, −3.0 ± 1.0 pmol · l−1 · h−1, P = 0.003). Although postprandial insulin levels were unaffected (ΔAUC, +20.8 ± 35.7 pmol · l−1 · h−1, P = 0.561), prandial glucose excursions were reduced (ΔAUC, −1.0 ± 0.3 mmol · l−1 · h−1, P &lt; 0.001), representing an ∼30% decrease relative to placebo. β-Cell function as assessed by the ISR AUC0–2 h/glucose AUC0–2 h was significantly increased (+6.4 ± 2.0 pmol · min−1 · m−2 · mmol · l−1, P = 0.002). Adverse event profiles were similar in the two treatment groups, and no hypoglycemia was reported.
CONCLUSIONS—The known effects of vildagliptin on incretin levels and islet function in type 2 diabetes were reproduced in subjects with IGT, with a 32% reduction in postprandial glucose excursions and no evidence of hypoglycemia or weight gain.
Physical activity for the prevention and management of youth-onset type 2 diabetes mellitus: focus on cardiovascular complications
Authors: Mcgavock Jonathan , Sellers Elizabeth , Dean Heather 
Published: December 2007

With the growing prevalence of childhood obesity and type 2 diabetes mellitus (T2DM) in youth, the challenge of cardiovascular disease risk management has entered the paediatric realm, affecting specialists, family physicians and allied healthcare professionals alike. Currently, there is little evidence to support optimal strategies for management of T2DM in youth and the associated cardiovascular complications. Physical activity plays a powerful role in the prevention and management of T2DM and cardiovascular disease in adults. This review will focus on the role of physical activity for the prevention of T2DM in youth and its associated cardiovascular complications. The first part describes the prevalence of cardiovascular risk factors in this cohort. The second part focuses on the role of physical activity in the prevention and management of T2DM in youth. Collectively, the limited intervention and observation studies published to date suggest that daily targets of 60–90 minutes of physical activity and less than 60 minutes of screen time (i.e. time spent in front of a television, computer or video games) are required for the prevention and management of T2DM in youth. Large-scale intervention studies are needed to determine the most effective physical activity strategies for the prevention and management of T2DM in youth.
Impact of metabolic syndrome definitions on prevalence estimates: a study in a Portuguese community
Authors: Santos Ana-Cristina , Barros Henrique 
Published: December 2007

This study compared the prevalence of metabolic syndrome (MS) according to World Health Organization (WHO), National Cholesterol Education Program Third Adult Treatment Panel (NCEP-ATP III), International Diabetes Federation (IDF) and American Heart Association/National Heart, Lung and Blood Institute (AHA/NHLBI) definitions, to evaluate how well the different classifications agreed. The study also compared their 10-year predicted risk of coronary heart disease (CHD) with the Framingham risk score (FRS). Some 886 women and 547 men aged 18–92 years were included in the study. Demographic and personal medical history data were obtained at interview. Four operational definitions of MS were used (those of the WHO, NCEP-ATP III, AHA/NHLBI and IDF). The prevalence of metabolic syndrome was found to be 26.4% (WHO criteria), 24.0% (NCEP-ATP III criteria), 41.9% (IDF criteria) and 37.2% (AHA/NHLBI criteria). According to the definition used, central obesity ranged from 41.9% to 75.1% and high blood pressure from 52.9% to 65.8%. Agreement between classifications ranged from 75.2% (κ=0.47) to 90.4% (κ=0.80) and was lower in males. The 10-year predicted risk of CHD by FRS was similar between the different definitions. IDF and AHA/NHLBI definitions resulted in a higher prevalence of MS than the NCEP-ATP III or WHO definition. Overall, however, good agreement was found between definitions, and the predicted 10-year of CHD risk was similar.
Double-edged relationship between adiposity and coronary artery calcification in type 1 diabetes
Authors: Conway Baqiyyah , Miller Rachel G , Costacou Tina , Fried Linda , Kelsey Sheryl , Evans Rhobert W , Edmundowicz Daniel , Orchard Trevor J 
Published: December 2007

Coronary artery disease (CAD), a leading cause of death in type 1 diabetes (T1D), often occurs two or more decades earlier in this population compared to the population without diabetes. Although CAD generally increases with adiposity, this association is unclear in T1D. In this study, we examined associations of adiposity with coronary artery calcium (CAC) in 315 individuals with T1D. Mean age and diabetes duration were 42 and 34 years, respectively, at study entry. CAC, visceral adiposity (VAT) and subcutaneous adiposity (SAT) were determined by electron beam tomography; and BMI and waist circumference (WC) were determined. The presence of CAC was positively associated with VAT, SAT and BMI in men (p<0.05) and with all four adiposity measures in women (p<0.05) after adjustment for age and other traditional cardiovascular risk factors. However, after adjustment, the degree of CAC was not associated with any of the four adiposity measures, with the exception of SAT in women. Women in the lowest tertile of SAT had more CAC than those in the second tertile (p<0.016). Adiposity was positively associated with the presence of CAC, but the relationship with its severity was either inverse or non-existent. This double-edged association emphasises the complex relationship between adiposity and cardiovascular risk in diabetes.
Admission glycaemia and outcome in patients with acute coronary syndrome
Authors: Müdespacher Damaris , Radovanovic Dragana , Camenzind Edoardo , Essig Manfred , Bertel Osmund , Erne Paul , Eberli Franz Robert , Gutzwiller Felix 
Published: December 2007

Some studies of patients with acute myocardial infarction have reported that hyperglycaemia at admission may be associated with a worse outcome. This study sought to evaluate the association of blood glucose at admission with the outcome of unselected patients with acute coronary syndrome (ACS). Using the Acute Myocardial Infarction and unstable angina in Switzerland (AMIS Plus) registry, ACS patients were stratified according to their blood glucose on admission: group 1: 2.80–6.99 mmol/L, group 2: 7.00–11.09 mmol/L and group 3: ≥ 11.10 mmol/L. Odds ratios for in-hospital mortality were calculated using logistic regression models. Of 2,786 patients, 73% were male and 21% were known to have diabetes. In-hospital mortality increased from 3% in group 1 to 7% in group 2 and to 15% in group 3. Higher glucose levels were associated with larger enzymatic infarct sizes (p<0.001) and had a weak negative correlation with angiographic or echographic left ventricular ejection fraction. High admission glycaemia in ACS patients remains a significant independent predictor of in-hospital mortality (adjusted OR 1.08; 95% confidence intervals [CI] 1.05–1.14, p<0.001) per mmol/L. The OR for in-hospital mortality was 1.04 (95% CI 0.99–1.1; p=0.140) per mmol/L for patients with diabetes but 1.21 (95% CI 112–1.30; p<0.001) per mmol/L for non-diabetic patients. In conclusion, elevated glucose level in ACS patients on admission is a significant independent predictor of in-hospital mortality and is even more important for patients who do not have known diabetes.
Beneficial effects of ramipril on myocardial diastolic function in patients with type 2 diabetes mellitus, normal LV systolic function and without coronary artery disease: a prospective study using tissue Doppler
Authors: Siegmund Thorsten , Schumm-Draeger Petra-Maria , Antoni Diethmar , Von Bibra Helene 
Published: December 2007

Angiotensin-converting enzyme (ACE) inhibitors can improve cardiovascular outcome in patients with type 2 diabetes mellitus (T2DM). Myocardial diastolic function (Ve) is a known marker of cardiovascular prognosis. It could potentially indicate the effects of preventive therapy if evaluated by tissue Doppler. We tested the hypothesis that treatment with the ACE inhibitor ramipril has beneficial effects on Ve. In this study, 16 subjects on insulin therapy (eight receiving 10 mg ramipril/day compared to eight matched controls who were not treated with an ACE inhibitor) were followed up for a period of nine months. Myocardial and vascular function were assessed by tissue Doppler and ultrasound. In the ramipril group, Ve improved significantly after nine months of treatment (7.8±0.9 cm/s to 8.6±0.9 cm/s, p<0.04). Systolic blood pressure and intima media thickness (IMT) demonstrated a trend towards improvement. In controls, Ve remained unchanged and there was a trend towards deterioration in stiffness index beta (p<0.07). In conclusion, the observed improvement of myocardial diastolic function with ramipril in patients with T2DM is an encouraging result. It might contribute to the overall improvement that has been observed with hard cardiovascular end points.
Microalbuminuria and the metabolic syndrome in non-diabetic black Africans
Authors: Okpechi Ikechi G , Pascoe Michael D , Swanepoel Charles R , Rayner Brian L 
Published: December 2007

It is recognised that the metabolic syndrome promotes the development of cardiovascular disease. Although several studies have shown a relationship between the metabolic syndrome and kidney disease, few of these have used non-diabetic subjects, especially in the African population. This was a cross-sectional study of subjects of African origin, using the metabolic syndrome (MS) criteria of the National Cholesterol Education Program (NCEP) third Adult Treatment Panel (ATP III). Subjects with impaired fasting glucose, with two-hour glucose ≥ 11.1 mmol/L after a glucose tolerance test, were excluded. Spot urine for albuminto-creatinine ratio (ACR) was measured and the glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease (MDRD) equation. Microalbuminuria was defined as ACR between 3–30 mg/mmol. There was a significant decline in GFR and a significant increase in ACR with increasing number of MS traits. ACR increased four-fold between subjects with no MS traits and those with four or more traits. In subjects with the metabolic syndrome, there was a significant correlation between ACR and systolic blood pressure (SBP), diastolic blood pressure (DBP) and fasting glucose. Estimated GFR correlated significantly and inversely with body mass index (BMI) and serum leptin. These observations raise major clinical and public health concerns for developing countries, where both the metabolic syndrome and kidney disease are being reported more and more frequently. The potential economic impact is huge.
Comparison of different ridge formation models of Arctic Sea ice with observations from laser profiling
Authors: Martin Torge 
Published: December 2007

AbstractSea ice deforms under convergent and Shear motion, causing rafting and ridging. This results in thicker ice than could be formed by thermodynamic growth only. Three different approaches to Simulating the formation of pressure ridges in a dynamic–thermodynamic continuum model are considered. They are compared with and evaluated by airborne laser profiles of the Sea-ice Surface roughness. The respective characteristic of each of the three ridging Schemes is (1) a prognostic equation for deformation energy from which ridge parameters are derived; (2) a redistribution function, Shifting ice between two categories, level and ridged, combined with a Monte Carlo Simulation for ridge parameters; and (3) prognostic equations for ridge density and height, resulting in the formation of ridged-ice volume. The model results Show that the ridge density is typically related to the State of ice motion, whereas the mean Sail height is related to the parent ice thickness. In general, all of the three models produce realistic distributions of ridges. Finally, the Second ridging Scheme is regarded as the most appropriate for climate modelling, while the third Scheme has advantages in Short-term Sea-ice forecasting.
A network model for fluid transport through sea ice
Authors: Zhu J. , Jabini A. , Golden K.M. , Eicken H. , Morris M. 
Published: December 2007

AbstractThe flow of liquid through porous sea ice is a fundamental process affecting problems in polar biology, oceanography and geophysics. The geometry and connectedness of the pore microstructure of sea ice determine its fluid permeability, which depends strongly on temperature. Here we analyze a simple pipe network as a basis for modeling fluid flow through the complex porous microstructure, and for numerical approximations of the fluid permeability of sea ice as a function of temperature. For slow flow the fluid system is equivalent to an electrical resistor network, and the network is solved using a fast multi-grid method. The radii of the pipes in the network are chosen randomly from distributions describing measured cross-sectional areas of brine inclusions in sea ice. At this stage, the model reflects only the most general features of brine microstructure and its evolution with temperature. Preliminary results for a basic implementation in two dimensions are presented. They are consistent with theoretical bounds on the vertical fluid permeability of sea ice found recently. Moreover, the results agree roughly with laboratory data for higher porosities. For lower porosities and colder temperatures, the fully connected network of pipes in the model, albeit with smaller radii, overestimates observed values. This finding provides evidence that the brine network becomes more disconnected with lower temperatures, which is consistent with transitional behavior near a percolation threshold.
Spatial variation of biogeochemical properties of landfast sea ice in the Gulf of Bothnia, Baltic Sea
Authors: Steffens M. , Granskog M.A. , Kaartokallio H. , Kuosa H. , Luodekari K. , Papadimitriou S. , Thomas D.N. 
Published: December 2007

AbstractHorizontal variation of landfast sea-ice properties was studied in the Gulf of Bothnia, Baltic Sea, during March 2004. In order to estimate their variability among and within different spatial levels, 72 ice cores were sampled on five spatial scales (with spacings of 10 cm, 2.5 m, 25 m, 250m and 2.5 km) using a hierarchical sampling design. Entire cores were melted, and bulk-ice salinity, concentrations of chlorophylla(Chla), phaeophytin (Phaeo), dissolved nitrate plus nitrite (DIN) as well as dissolved organic carbon (DOC) and nitrogen (DON) were determined. All sampling sites were covered by a 5.5–23 cm thick layer of snow. Ice thicknesses of cores varied from 26 to 58 cm, with bulk-ice salinities ranging between 0.2 and 0.7 as is typical for Baltic Sea ice. Observed values for Chla(range: 0.8–6.0 mg ChlaL–1; median: 2.9 mg ChlaL–1) and DOC (range: 37–397 μM; median: 95 μM) were comparable to values reported by previous sea-ice studies from the Baltic Sea. Analysis of variance among different spatial levels revealed significant differences on the 2.5km scale for ice thickness, DOC and Phaeo (with the latter two being positively correlated with ice thickness). For salinity and Chla, the 250 m scale was found to be the largest scale where significant differences could be detected, while snow depth only varied significantly on the 25 m scale. Variability on the 2.5 m scale contributed significantly to the total variation for ice thickness, salinity, Chlaand DIN. In the case of DON, none of the investigated levels exhibited variation that was significantly different from the considerable amount of variation found between replicate cores. Results from a principal component analysis suggest that ice thickness is one of the main elements structuring the investigated ice habitat on a large scale, while snow depth, nutrients and salinity seem to be of secondary importance.
A one-dimensional enthalpy model of sea ice
Authors: Notz Dirk , Grae Worster M. 
Published: December 2007

AbstractWe present a 1-D enthalpy-based model of sea ice that allows for quantitative studies of sea ice and its interaction with radiative processes, melt ponds, oceanic heat and salt fluxes, internal density changes and surface heat fluxes on a single computational domain. The model provides new insight into the interior structure and the salinity evolution of sea ice. We compare our model results with measurements from laboratory experiments and show for example that no salt is lost from sea ice by brine expulsion.
Energy- and mass-balance observations of the land–ice–ocean–atmosphere system near Barrow, Alaska, USA, November 1999–July 2002
Authors: Grenfell Thomas C. , Perovich Donald K. , Eicken Hajo , Light Bonnie , Harbeck Jeremy , George Thomas H. , Mahoney Andrew 
Published: December 2007

AbstractWe present results from a comprehensive field study carried out near Barrow, Alaska, USA, designed to characterize local- to intermediate-scale sea-ice processes in the Arctic coastal zone of central importance to the annual cycle and evolution of the coastal sea ice. Included in this are the behavior of the snow cover of the ice and adjacent tundra and lake system; concurrent studies of mass balance of the sea ice and lake ice; interaction of shortwave radiation with the shore-fast ice and the adjacent land surfaces; evolution of the area coverage and distribution of the various surface types; and the resulting regional albedo values. Maximum snow depths decreased during 2000–02 from 0.38 m to 0.26 m. Ice-melt rates in 2001 were 0.05 and 0.028md–1at the top and bottom of the sea ice respectively, two to three times larger than observations from the central Arctic. Detailed surface results combined with aircraft photography were used to calculate regional albedos for the late spring and early summer of 2001. Values ranged from 0.8 for all cold snow-covered surfaces to approximately 0.4 for melting sea ice and lake ice vs 0.18 for bare tundra. Regional and surface-based values of cumulative shortwave radiation entering the ice were consistent, indicating that albedo sampling on a scale of 200m can provide a useful representation for regional sea-ice albedo.
Relation of ice growth rate to salt segregation during freezing of low-salinity sea water (Bothnian Bay, Baltic Sea)
Authors: Granskog Mats A. , Uusikivi Jari , Blanco Sequeiros Alberto , Sonninen Eloni 
Published: December 2007

AbstractSalt segregation and isotopic fractionation during sea-ice formation can be parameterized as a function of the ice growth rate. We performed a study to investigate if the salt segregation models derived for saline sea-ice studies are pertinent during the growth of Baltic Sea ice in brackish water. We used a time series of ice-salinity profiles and modeled growth rates to examine the relationship between effective salt segregation and growth rate. The results show that models derived for saline sea water are not directly applicable for use in the brackish waters of the Baltic Sea. We derived a simple model for the effective salt segregation in relation to ice growth rate, for a wide range of growth rates, pertinent for use in low-salinity Baltic Sea conditions and in the future development of a Baltic Sea ice salinity model.
Modelling of superimposed ice formation during the spring snowmelt period in the Baltic Sea
Authors: Cheng Bin , Vihma Timo , Pirazzini Roberta , Granskog Mats A. 
Published: December 2007

AbstractDevelopment of landfast sea ice and its snow cover was monitored in the Gulf of Bothnia, Baltic Sea, for a period of 4 weeks during the early melt season of 2004. During this period, approximately 90% of the snow layer was transformed into superimposed ice, while the rest sublimated. A one-dimensional thermodynamic snow/ice model was used to simulate this process. The modelled snowmelt and superimposed ice growth were consistent with the observations, but the net accumulation of superimposed ice was slightly overestimated. The errors in calculation of temporal variations of the refreezing were probably due to the uncertainties in the external forcing and simplification of snow processes in the model. The modelled snow thickness was sensitive to the atmospheric forcing, and the influence was amplified when the albedo was parameterized as a function of surface temperature. In the sensitivity tests without this feedback, the direct effect of the inaccuracy in the albedo parameterization was minor. Errors in the parameterized longwave radiation were critical for the modelled snow surface temperature during night-time, but did not have a large effect on the mass balance during this spring melt period.
Wave measurements on sea ice: developments in instrumentation
Authors: Doble M.J. , Mercer D.J.L. , Meldrum D.T. , Peppe O.C. 
Published: December 2007

AbstractTraditional methods of measuring the propagation of waves originating from ocean swell and other sources have relied on wire strain gauges, accelerometers or tiltmeters. All methods required constant attention to keep in range, while data recovery has demanded that the instrument site be revisited. In this paper, we describe the use of ultra-sensitive tiltmeters and novel re-zeroing techniques to autonomously gather wave data from both polar regions. A key feature of our deployments has been the use of the Iridium satellite communications system as a way of ensuring continuous data recovery and remote control of the instrumentation. Currently four instruments have been successfully reporting from the Arctic Ocean for over 18 months, with two further units deployed in 2005, one in the Weddell Sea, Antarctica, and one additional unit in the Arctic.