bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Sodium Nitroprusside Toxicity in Pediatric Cardiac Surgical Patients
Authors: Moffett Brady Scott , Price Jack F 
Published: October 2008

Background: Sodium nitroprusside (SNP) is often used in postoperative pediatric cardiac surgical patients. Cyanide toxicity may occur with the use of SNP. There is a paucity of literature describing dosing parameters or physical signs and symptoms of toxicity with SNP. Objective: To determine the incidence of cyanide toxicity in postoperative pediatric cardiac surgical patients treated with SNP and identify dosing parameters and physical signs and symptoms that may predict elevated cyanide concentrations. Methods: Medical records of patients who received SNP in the pediatric cardiac intensive care unit from January 2002 through December 2002 were identified and evaluated for cyanide and thiocyanate levels, dosing, and signs and symptoms of toxicity. Patients were included if they had received SNP after cardiac surgery, were 18 years of age or less, and had at least one cyanide or thiocyanate level determined while receiving therapy. Patients were excluded if they had received sodium thiosulfate. The Mann-Whitney U test was used to determine significant differences in mean dose, duration of infusion, renal function, serum lactate, and acid-base status between groups with elevated or nonelevated levels. Logistic regression and receiver operator curve were used to determine variables associated with elevated levels. Relationships between signs and symptoms of toxicity and elevated levels were evaluated with Fisher's exact test. Results: Cyanide concentrations were in the toxic range in 7 of 63 (11%) patients. Patients with elevated concentrations had significantly higher mean dose, cumulative dose, and acid-base excess values. Elevated cyanide levels were independently predicted by mean dose, cumulative dose, and acid-base excess values, and a dose of 1.8 μg/kg/min predicted an elevated cyanide concentration with 89% sensitivity and 88% specificity. Adverse events were not reliable predictors of elevated cyanide levels. Conclusions: Mean dose of SNP is the best predictor of elevated cyanide levels. Adverse events commonly associated with cyanide toxicity may not be reliable indicators of elevated cyanide concentrations.
Genetic (RAPD) Diversity Across Species Range: Core vs. Peripheral Populations of Wild Barley in Israel and Turkmenistan
Authors: Shulgina Irina , Yakubov Bahtiyor , Orlovsky Nikolai , Mendlinger Samuel , Shulgina Irina , Volisc Sergei 
Published: October 2008

Populations of wild barley,Hordeum spontaneum, were collected in two countries, Israel and Turkmenistan, in environments representing two similar sharp clines of aridity. This allowed us to use the same criteria to define species core and periphery in the two regions. Plants from 21 Israeli and 11 Turkmenian populations were analyzed for 59 putative loci by randomly amplified polymorphic DNA. Extent of variation was similar in populations at species border (periphery) and in populations inhabiting favorable environments away from the border (core). In contrast, the two regions (Israel and Turkmenistan) differed in extent of genetic diversity as estimated by mean number of alleles per locus, the proportion of polymorphic loci, and the percent of expected heterozygosity, with Israel harboring more variation than Turkmenistan. The genetic population structure revealed by RAPDs did not differ between species core and periphery in each region and between the two regions. The pattern of RAPD variation corresponded to inter-population mosaic structure characterized by genetic differentiation over short geographic distances.The major conclusion of this study is that there is no simple relationship between neutral genetic variability and population location with respect to the species range (core vs. periphery).
Evolution of the Circadian Clock Mechanism in Prokaryotes
Authors: Dvornyk Volodymyr 
Published: October 2008

The circadian system of prokaryotes is probably the oldest among the circadian systems of living organisms. The genes comprising the system are very different in their evolutionary histories. The reconstruction of macroevolution of the circadian genes in cyanobacteria suggests that there are probably at least two types of circadian systems, based either on the threekaigenes (kaiA, kaiB, andkaiC) or onkaiBandkaiC.When referred to the recently published results about a genomic timescale of prokaryote evolution, the origin ofkaiBandsasAcorresponds to the appearance of anoxygenic photosynthesis, while the origin of thekaiBCoperon corresponds to the time when oxygenic photosynthesis evolved.The results of the studies performed so far suggest that major steps in macroevolution of the circadian system in cyanobacteria have been related to global changes in the environment and to keystone advances in biological evolution. This macroevolution has involved selection, multiple lateral transfers, gene duplications, and fusions as its primary driving forces. The proposed scenario of the circadian system's macroevolution is far from complete and will be updated as new genomic and sequence data are accumulated.
Modeling the Evolutionary and Ecological Consequences of Selection and Adaptation in Heterogeneous Environments
Authors: Cohen Dan 
Published: October 2008

The evolution of adaptations of natural populations in heterogeneous environments poses many challenges. According to the conventional paradigm of adaptive evolution, most traits of existing organisms should be well adapted to the whole wide range of conditions to which they are exposed in their natural environments. However, many traits in most organisms appear to be poorly adapted at many specific conditions, while many other traits appear to be well adapted to conditions that occur only very rarely or not at all in their natural environment. At the same time, many apparently available resources are exploited very little or not at all by the existing species in ecological communities.
To help account for these discrepancies and contradictions, I model the effects of the frequency distribution of the contributions to reproductive output of different conditions, habitats, and events, and the major effects of the correlations between the selection forces at different conditions on the selection and adaptation of each of the characteristic traits of species in naturally heterogeneous environments.
The force of selection at any one condition i is proportional to the reproductive output fraction Fi of the exposed population. Fi is the product of the population fraction Hi and the individual reproductive output Ri.
Selection at any one locus or trait A in a large mixed population establishes an allele or trait A* that maximizes the mean fitness
W⁁(A) = Σi[(Wi(A)Fi], weighted over all conditions according to the product of their fitness functions and relative reproductive outputs. Consequently, the adaptation of any trait to any one rare specific condition depends very little on the specific selection coefficient! Specific adaptations depend almost only on the correlations between the fitness of the overall optimal trait A* and the fitness of the specific optimal trait Ai* at the specific condition. Thus, species are expected to be better adapted and to exploit mostly their more abundant and more positively correlated resources.
The consequences for ecological communities are that superior competitive species are not likely to evolve to exclude coexisting rare species that exploit rare negatively correlated habitats.
Also, the exploitation by any one species of a range of resources with negatively correlated fitness functions is genetically and ecologically unstable. Such resources may remain unexploited by existing species. Opening a large new habitat may select against adaptation for some previously utilized resources with negatively correlated fitness functions, but may select for adaptation for some previously unutilized rare resources or habitats with positively correlated fitness functions. The opposite effects are predicted for the elimination of some large utilized resource.
Catecholaminergic Effects on Ventricular Repolarization During Inhibition of the Rapid Component of the Delayed Rectifier Potassium Current in a Perfused Heart Model
Authors: Overholser Brian R. , Zheng Xiaomei , Tisdale James E. 
Published: October 2008

Study Objective. To determine the catecholaminergic effects on the duration of ventricular repolarization during inhibition of the rapid component of the delayed rectifier potassium current (IKr).Design. Isolated perfused heart model.Setting. University research center.Animals. Eighteen male Dunkin‐Hartley guinea pigs.Intervention. Hearts were excised and perfused in a retrograde manner at a constant aortic pressure of 60 mm Hg and temperature of 37°C. Thirteen hearts were administered sparfloxacin 20 μg/ml (an IKrinhibitor) in a buffered solution; the remaining five hearts were perfused with only the buffered solution to act as controls for potential time‐dependent changes in action potential duration (APD). Immediately after the sparfloxacin infusion, six of the 13 hearts were administered a bolus catecholamine infusion of an epinephrine 10 nM‐norepinephrine 6 nM admixture; 10 minutes after the start of the first catecholamine infusion, these hearts received another bolus infusion of an epinephrine 5 nM‐norepinephrine 3 nM admixture. The other seven hearts were administered only a buffered solution.Measurements and Main Results. Hearts were paced (240 beats/min), and left ventricular monophasic action potentials were recorded for determination of APD at 90% and 30% repolarization (APD90and APD30, respectively). The APD90and APD30increased in all 13 hearts exposed to sparfloxacin. The mean ± SD APD90increase from baseline at 15 minutes was 4.2 ± 2.5% relative to the five control hearts. In the presence of IKrinhibition, the epinephrine 5 nM‐norepinephrine 3 nM and epinephrine 10 nM‐norepinephrine 6 nM admixtures altered APD90, with a mean ± SD maximum increase in APD90of 3.1 ± 1.2% and 4.5 ± 3.6%, respectively. This corresponded to a statistically significant increase in APD90and APD302 minutes after the catecholamine infusion in the presence of IKrinhibition.Conclusion. A net prolongation of ventricular repolarization was observed after a catecholamine surge in the presence of mild IKrinhibition. This suggests that counteracting mechanisms may contribute to the apparent arrhythmogenic substrate during nonspecific adrenergic receptor activation in the presence of IKrinhibition.
β-Cell Mass and Type 1 Diabetes
Authors: Akirav Eitan , Kushner Jake A. , Herold Kevan C. 
Published: October 2008

OBJECTIVE— β-Cell regeneration is a fundamental but elusive goal for type 1 diabetes research. Our objective is to review newer human and animal studies of β-cell destruction and regeneration and consider the implications for treatment of type 1 diabetes.
RESEARCH DESIGN AND METHODS— Recent human and animal studies of β-cell destruction and regeneration in type 1 diabetes are reviewed.
RESULTS— The loss of β-cells that characterizes type 1 diabetes reflects the net effects of destruction and regeneration. These processes have been examined in the nonobese diabetic (NOD) mouse; uncertainty remains about β-cell dynamics in humans. Islet inflammation stimulates β-cell replication that produces new insulin-positive cells. The regenerative process may tide the loss of overall β-cell function, but it also may enhance the autoimmune attack on β-cells by providing new epitopes. The highest rates of β-cell replication are at the time of diagnosis of diabetes in NOD mice, and if autoimmunity and islet inflammation are arrested, new β-cells are formed. However, the majority of β-cells after treatment with immune modulators such as anti-CD3 monoclonal antibody, and most likely during the “honeymoon” in human disease, are recovered β-cells that had been degranulated but present at the time of diagnosis of diabetes.
CONCLUSIONS— Residual β-cells play a significant role for the design of therapeutic trials: they not only may respond to combination therapies that include stimulants of metabolic function but are also the potential source of new β-cells.
Effects of High-Dose Simvastatin Therapy on Glucose Metabolism and Ectopic Lipid Deposition in Nonobese Type 2 Diabetic Patients
Authors: Szendroedi Julia , Anderwald Christian , Krssak Martin , Bayerle-Eder Michaela , Esterbauer Harald , Pfeiler Georg , Brehm Attila , Nowotny Peter , Hofer Astrid , Waldhäusl Werner , Roden Michael 
Published: October 2008

OBJECTIVE—Statins may exert pleiotropic effects on insulin action that are still controversial. We assessed effects of high-dose simvastatin therapy on peripheral and hepatic insulin sensitivity, as well as on ectopic lipid deposition in patients with hypercholesterolemia and type 2 diabetes.
RESEARCH DESIGN AND METHODS—We performed a randomized, double-blind, placebo-controlled, single-center study. Twenty patients with type 2 diabetes received 80 mg simvastatin (BMI 29 ± 4 kg/m2, age 55 ± 6 years) or placebo (BMI 27 ± 4 kg/m2, age 58 ± 8 years) daily for 8 weeks and were compared with 10 healthy humans (control subjects; BMI 27 ± 4 kg/m2, age 55 ± 7 years). Euglycemic-hyperinsulinemic clamp tests combined with d-[6,6-d2]glucose infusion were used to assess insulin sensitivity (M) and endogenous glucose production (EGP). 1H magnetic resonance spectroscopy was used to quantify intramyocellular and hepatocellular lipids.
RESULTS—High-dose simvastatin treatment lowered plasma total and LDL cholesterol levels by ∼33 and ∼48% (P &lt; 0.005) but did not affect M, intracellular lipid deposition in soleus and tibialis anterior muscles and liver, or basal and insulin-suppressed EGP. In simvastatin-treated patients, changes in LDL cholesterol related negatively to changes in M (r = −0.796, P &lt; 0.01). Changes in fasting free fatty acids (FFAs) related negatively to changes in M (r = −0.840, P &lt; 0.01) and positively to plasma retinol-binding protein-4 (r = 0.782, P = 0.008).
CONCLUSIONS—High-dose simvastatin treatment has no direct effects on whole-body or tissue-specific insulin action and ectopic lipid deposition. A reduction in plasma FFAs probably mediates alterations in insulin sensitivity in vivo.
Prevalence of Pre-Diabetes and Its Association With Clustering of Cardiometabolic Risk Factors and Hyperinsulinemia Among U.S. Adolescents
Authors: Li Chaoyang , Ford Earl S. , Zhao Guixiang , Mokdad Ali H. 
Published: October 2008

OBJECTIVE—Impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) are considered to constitute “pre-diabetes.” We estimated the prevalence of IFG, IGT, and pre-diabetes among U.S. adolescents using data from a nationally representative sample.
RESEARCH DESIGN AND METHODS—We analyzed data from participants aged 12–19 years in the National Health and Nutrition Examination Survey 2005–2006. We used fasting plasma glucose and 2-h glucose during an oral glucose tolerance test to assess the prevalence of IFG, IGT, and pre-diabetes and used the log-binomial model to estimate the prevalence ratios (PRs) and 95% CIs.
RESULTS—The unadjusted prevalences of IFG, IGT, and pre-diabetes were 13.1, 3.4, and 16.1%, respectively. Boys had a 2.4-fold higher prevalence of pre-diabetes than girls (95% CI 1.3–4.3). Non-Hispanic blacks had a lower rate than non-Hispanic whites (PR 0.6, 95% CI 0.4–0.9). Adolescents aged 16–19 years had a lower rate than those aged 12–15 years (0.6, 0.4–0.9). Overweight adolescents had a 2.6-fold higher rate than those with normal weight (1.3–5.1). Adolescents with two or more cardiometabolic risk factors had a 2.7-fold higher rate than those with none (1.5–4.8). Adolescents with hyperinsulinemia had a fourfold higher prevalence (2.2–7.4) than those without. Neither overweight nor number of cardiometabolic risk factors was significantly associated with pre-diabetes after adjustment for hyperinsulinemia.
CONCLUSIONS—Pre-diabetes was highly prevalent among adolescents. Hyperinsulinemia was independently associated with pre-diabetes and may account for the association of overweight and clustering of cardiometabolic risk factors with pre-diabetes.
YKL-40, a Marker of Inflammation and Endothelial Dysfunction, Is Elevated in Patients With Type 1 Diabetes and Increases With Levels of Albuminuria
Authors: Rathcke Camilla Noelle , Persson Frederik , Tarnow Lise , Rossing Peter , Vestergaard Henrik 
Published: October 2008

OBJECTIVE—The inflammation marker YKL-40 is elevated in patients with type 2 diabetes and is associated with atherosclerosis and increased cardiovascular mortality. In the present study, YKL-40 levels were examined in patients with type 1 diabetes with increasing levels of albuminuria, known to be associated with an increased risk of cardiovascular disease.
RESEARCH DESIGN AND METHODS—A total of 149 patients with type 1 diabetes attending Steno Diabetes Center were examined: 58 had normoalbuminuria (urinary albumin excretion rate &lt;30 mg/24 h), 46 had persistent microalbuminuria (urinary albumin excretion rate 30–300 mg/24 h), and 45 had persistent macroalbuminuria/diabetic nephropathy (urinary albumin excretion rate &gt;300 mg/24 h). The control group consisted of 55 healthy individuals. Groups were matched according to sex and duration of diabetes (&gt;30 years).
RESULTS—Median levels [interquartile range] of serum YKL-40 were significantly higher in normoalbuminuria versus control (37 [29–52] vs. 53 [32–105] ng/ml, P &lt; 0.01) and were increasing with increasing levels of albuminuria (microalbuminuria 74 [45–160] ng/ml and diabetic nephropathy 117 [68–215] ng/ml; P &lt; 0.001 for all comparisons). YKL-40 levels correlated with the urinary albumin-to-creatinine ratio in the total group of participants (r2 = 0.25, P &lt; 0.001). Significant but weak intercorrelations of YKL-40 were found with age, diastolic blood pressure, A1C, and serum creatinine. After adjustment for significant covariates, albuminuria was significantly associated with YKL-40 levels (P &lt; 0.001).
CONCLUSIONS—YKL-40 levels are elevated in patients with type 1 diabetes with an independent association between increasing YKL-40 levels and increasing levels of albuminuria. The present study is the first to suggest a role of YKL-40 in the gradually progressing vascular complications in patients with type 1 diabetes.
Oral Disposition Index Predicts the Development of Future Diabetes Above and Beyond Fasting and 2-h Glucose Levels
Authors: Utzschneider Kristina M. , Prigeon Ronald L. , Faulenbach Mirjam V. , Tong Jenny , Carr Darcy B. , Boyko Edward J. , Leonetti Donna L. , McNeely Marguerite J. , Fujimoto Wilfred Y. , Kahn Steven E. 
Published: October 2008

OBJECTIVE—We sought to determine whether an oral disposition index (DIO) predicts the development of diabetes over a 10-year period. First, we assessed the validity of the DIO by demonstrating that a hyperbolic relationship exists between oral indexes of insulin sensitivity and β-cell function.
RESEARCH DESIGN AND METHODS—A total of 613 Japanese-American subjects (322 men and 291 women) underwent a 75-g oral glucose tolerance test (OGTT) at baseline, 5 years, and 10 years. Insulin sensitivity was estimated as 1/fasting insulin or homeostasis model assessment of insulin sensitivity (HOMA-S). Insulin response was estimated as the change in insulin divided by change in glucose from 0 to 30 min (ΔI0–30/ΔG0–30).
RESULTS—ΔI0–30/ΔG0–30 demonstrated a curvilinear relationship with 1/fasting insulin and HOMA-S with a left and downward shift as glucose tolerance deteriorated. The confidence limits for the slope of the loge-transformed estimates included −1 for ΔI0–30/ΔG0–30 versus 1/fasting insulin for all glucose tolerance groups, consistent with a hyperbolic relationship. When HOMA-S was used as the insulin sensitivity measure, the confidence limits for the slope included −1 only for subjects with normal glucose tolerance (NGT) or impaired fasting glucose (IFG)/impaired glucose tolerance (IGT) but not diabetes. On the basis of this hyperbolic relationship, the product of ΔI0–30/ΔG0–30 and 1/fasting insulin was calculated (DIO) and decreased from NGT to IFG/IGT to diabetes (P &lt; 0.001). Among nondiabetic subjects at baseline, baseline DIO predicted cumulative diabetes at 10 years (P &lt; 0.001) independent of age, sex, BMI, family history of diabetes, and baseline fasting and 2-h glucose concentrations.
CONCLUSIONS—The DIO provides a measure of β-cell function adjusted for insulin sensitivity and is predictive of development of diabetes over 10 years.
Average entanglement of spin 1 and 1/2 pair
Authors: Zhu Guo-Qiang 
Published: October 2008

Abstract
We study the entanglement features of the ground state of a system composed of spin 1 and 1/2 parts. In the light of the ground state degeneracy, the notion of average entanglement is used to measure the entanglement of the Hilbert subspace. The entanglement properties of both a general superposition as well as the mixture of the degenerate ground states are discussed by means of average entanglement and the negativity respectively.
Livelihood Choices and Returns among Pastoralists: Evidence from Southern Kenya
Authors: Radeny Maren , Nkedianye David , Kristjanson Patricia , Herrero Mario 
Published: October 2008

Abstract
Pastoral systems are rapidly changing in Africa and elsewhere, yet relatively little is known regarding what, and how well, households in these systems are now doing. This article addresses livelihood choices and income diversification strategies in a traditionally Maasai pastoral area of southern Kenya, and the factors influencing the returns to their diverse livelihood strategies. We explore how well household-level versus geographic factors explain the large variability in income and livestock wealth levels and the implications for wildlife conservation and poverty reduction strategies.
Making Pastoral Settlement Visible in China
Authors: Zukosky Michael L. 
Published: October 2008

Abstract
Seen in the built environment of village and towns, the plans of scientific texts and journals of modern animal husbandry, and in the programmes of state natural resource bureaucracies and international development projects, settlements constructed for nomadic peoples in China seem to index a historically and socially specific vision associated with modern political economic ideologies. Drawing on the work of James Scott (1996), one might argue that settlement is the vision of the Chinese state. Yet Scott's approach risks objectifying the embodied vision of the humans who constitute settlement. Indeed, many scholars have simplified the agency attributed to a range of actors within the experience of settlement. This article uses a phenomenological approach to make more complex our understandings of these phenomena by exploring perceptions of settlement among three distinct actors: officials from the Chinese states, personnel of international organizations which have funded and provided technical expertise in the implementation of settlements, and residents of settlements themselves - Chinese ethnic minority citizens. In conclusion, I offer three different but overlapping visions that make settlement as a totality possible, and yet distinct from an objectified vision of Chinese government officials.