bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of artificial and natural barriers on the movement of small mammals in Banff National Park, Canada
Authors: Robert McDonald Wayne , Cassady St. Clair Colleen
Published: March 2004

Barriers that dissect continuous habitat, such as roads, initiate the process of habitat fragmentation and can filter or eliminate animal movement through otherwise pristine areas. A severe road barrier appears to exist in Banff National Park where the Trans‐Canada Highway (TCH) is known to impede the movement of some animals, but the effects of this barrier relative to natural barriers and continuous habitat have not been assessed. To compare animal movement in response to these three contexts, we translocated three species of murid rodents (meadow voles,Microtus pennsylvanicus, deer mice,Peromyscus maniculatus, and red‐backed voles,Clethrionomys gapperi) across the TCH (an artificial barrier), a forested strip in the median of the TCH (a natural barrier), in the adjacent highway verge (continuous grassy) and in nearby forest (continuous forested). We coated murids with fluorescent dye, released them at standardized distances, and followed the resulting trails to obtain detailed information on movement paths. Overall, individuals were 20% less successful crossing the TCH than natural (forested) barriers and 10% less successful crossing natural barriers than continuous habitat, but exhibited marked variation among species. Path tortuosity was negatively related to return success; more convoluted paths were associated with lower success across all treatments. Deer mice returned to their home‐ranges more often than the other two species, perhaps because of their generalist habitat preferences, nocturnal activities, or larger home ranges. In all treatments, the fractal dimensions of movement paths were very qualitatively similar to those observed for return success and tortuosity, indicating that the responses of these species were not influenced by spatial scale. Together, our results suggest that (a) murid species differ in the movement limitation imposed by both natural and artificial barriers, perhaps as a consequence of differences in habitat preferences and activity patterns, and (b) murid responses to a road barrier are only moderately different from responses to the natural barrier of a forest edge in the context of translocation experiments.
Are invasive plant species better competitors than native plant species? – evidence from pair‐wise experiments
Authors: Vilà Montserrat , Weiner Jacob
Published: March 2004

Invasive plants often appear to be more competitive than native species, but there have been few tests of this hypothesis. We reviewed published pair‐wise experiments between invading and native plant species. Although the designs that have been used allow only limited inferences, the available data suggest that the effect of invasive species on native species is usually stronger than vice versa. Furthermore, mixtures of invasive and native species are generally less productive than monocultures of the native species, but not less than monocultures of the invasive species. However, the selection of invaders and natives for study has not been random, and the data could be biased towards highly competitive invaders and natives that are weaker than average competitors. We attempt to clarify confusion surrounding the concept of competitive superiority in the context of plant invasions, and we discuss the limitations of the methods that have been used to investigate competition between invasive and native species. To rigorously test the generality of the hypothesis that invaders are better competitors than natives we need to compare the effects of closely related native and invasive species on each other. We suggest that the influence of an invading species on total plant community biomass is an important clue in understanding the role of competition in a plant invasion. The role of competition in the establishment and naturalization stages of the invasion process may be very different from its role in the “outbreak” stage.
Reindeer influence on ecosystem processes in the tundra
Authors: Olofsson J. , Stark S. , Oksanen L.
Published: March 2004

Reindeer have been recorded to increase nutrient cycling rate and primary production in studies from fences almost 40 years old that separate areas with different grazing regimes in northern Fennoscandia. To further understand the mechanism behind the effects of herbivores on primary production, we measured the size of the major C and N pools, soil temperature, litter decomposition rate and N mineralization rate in lightly, moderately and heavily grazed areas along two of these fences.

Plant N found in new biomass, indicative of plant N assimilation, was significantly higher in moderately and heavily grazed areas than in lightly grazed areas, which corresponded to a decreased amount of N in old plant parts. The amount of N found in plant litter or organic soil layer did not differ between the grazing treatments. Together with soil N concentrations and litter decomposition rates, soil temperatures were significantly higher in moderately and heavily grazed areas.

We conclude that the changes in soil temperature are important for the litter decomposition rate and thus on the nutrient availability for plant uptake. However, the changes in plant community composition appear to be more important for the altered N pools and thus the enhanced primary production. The results provide some support for the keystone herbivore hypothesis, which states that intensive grazing can promote a transition from moss‐rich tundra heath to productive grasslands. Grazing altered N fluxes and pools, but the total N pools were similar in all grazing treatments. Our study thus indicates that grazing can increase the primary production through enhancing the soil nutrient cycling rate, even in a long term perspective on an ecological timescale.
The significance of bottom‐up effects for host plant specialization in Chrysomela leaf beetles
Authors: Gross Jürgen , Fatouros Nina E. , Hilker Monika
Published: March 2004

The leaf beetle species Chrysomela lapponica, which belongs to the so‐called C. interrupta group, forms distinct allopatric populations either on willows (Salicaceae) or birches (Betulaceae). It was recently suggested that, on several occasions, host plant shifts from Salicaceae to Betulaceae occurred independently within the C. interrupta group. Our study aims to elucidate bottom‐up effects of the host plants that might have shaped the evolution of host plant specialization in the populations of C. lapponica, and thus, to shed some light on the driving forces of host shifts within the C. interrupta group, too. We compared the oviposition behaviour and performance of two C. lapponica populations, one of which has adapted to birches and the other to willows. The studies were conducted under laboratory conditions, eliminating the impact of natural enemies. Experiments involving the transfer of individuals of the birch‐specialized population to willows and vice versa with individuals of the willow‐specialized population to birches aimed to examine the plasticity in host plant use. Females of each population almost exclusively chose their natural host plant for oviposition, when offering birch and willow in dual choice experiments. When specimens of the two C. lapponica populations were reared on their natural host plants, the birch specialists suffered higher mortality, needed a longer period of development and produced less larval defensive secretion than the willow specialists. When the birch specialists were fed with willow, these performance parameters decreased even more. Other parameters, such as body weight and fecundity, did not differ between birch and willow specialists when they were fed with their natural host plant. While individuals of the birch‐specialized population could be reared on willow, all neonate larvae from the willow‐specialized population died after being transferred to birch. The significance of these bottom‐up effects for the evolution of host plant specialization in C. lapponica is discussed.
Valuation by Simulation of Contingent Claims with Multiple Early Exercise Opportunities
Authors: Ibáñez Alfredo
Published: March 2004

This paper introduces the application of Monte Carlo simulation technology to the valuation of securities that contain many (buying or selling) rights, but for which a limited number can be exercised per period, and penalties if a minimum quantity is not exercised before maturity. These securities combine the characteristics of American options, with the additional constraint that only a few rights can be exercised per period and therefore their price depends also on the number of living rights (i.e., American‐Asian‐style payoffs), and forward securities. These securities give flexibility‐of‐delivery options and are common in energy markets (e.g., take‐or‐pay or swing options) and as real options (e.g., the development of a mine). First, we derive a series of properties for the price and the optimal exercise frontier of these securities. Second, we price them by simulation, extending theIbáñez and Zapatero (2004)method to this problem.
Exercise Regions And Efficient Valuation Of American Lookback Options
Authors: Lai Tze Leung , Lim Tiong Wee
Published: March 2004

This paper presents an efficient method to compute the values and early exercise boundaries of American fixed strike lookback options. The method reduces option valuation to a single optimal stopping problem for standard Brownian motion and an associated path‐dependent functional, indexed by one parameter in the absence of dividends and by two parameters in the presence of a dividend rate. Numerical results obtained by this method show that, after a space‐time transformation, the stopping boundaries are well approximated by certain piecewise linear functions with a few pieces, leading to fast and accurate approximations for American lookback option values. An explicit decomposition formula for American lookback options is derived and applied not only to the development of these approximations but also to the asymptotic analysis of the early exercise boundary near the expiration date.
Asymptotics of the price oscillations of a European call option in a tree model
Authors: Diener Francine , Diener MARC
Published: March 2004

It is well known that the price of a European vanilla option computed in a binomial tree model converges toward the Black‐Scholes price when the time step tends to zero. Moreover, it has been observed that this convergence is of order 1/n in usual models and that it is oscillatory. In this paper, we compute this oscillatory behavior using asymptotics of Laplace integrals, giving explicitly the first terms of the asymptotics. This allows us to show that there is no asymptotic expansion in the usual sense, but that the rate of convergence is indeed of order 1/n in the case of usual binomial models since the second term (in ) vanishes. The next term is of type C2(n)/n, with C2(n) some explicit bounded function of n that has no limit when n tends to infinity.
3‐Azido‐aspartic acid derivatives – orthogonally protected precursors for the stereoselective incorporation of 2,3‐diaminosuccinic acid into peptide structures
Authors: Riemer C. , Bayer T. , Schmitt H. , Kessler H.
Published: March 2004

Abstract:  The stereoselective synthesis of orthogonally protected 3‐azido aspartic acid derivatives is described. The convenience of their application as 2,3‐diaminosuccinic acid in peptide chemistry was demonstrated by the incorporation of the nonproteinogenic diamino diacid as a cystine‐substitute into the core structure of somatostatin.
Ninhydrin as a reversible protecting group of amino‐terminal cysteine
Authors: Pool C.T. , Boyd J.G. , Tam J.P.
Published: March 2004

Abstract:  The proximity of the α‐amine and β‐thiol of α‐amino terminal‐cysteine (NT‐Cys) residues in peptides imparts unique chemical properties that have been exploited for inter‐ and intra‐molecular ligation of unprotected peptides obtained through both synthetic and biological means. A reversible protecting group orthogonal to other protection strategies and reversible under mild conditions would be useful in simplifying the synthesis, cleavage, purification and handling of such NT‐Cys peptides. It could also be useful for the sequential ligation of peptides. To this end, we explored tri‐one chemistry and found that ninhydrin (indane‐1,2,3 trione) reacted readily with cysteine or an NT‐Cys‐containing peptide on‐ or off‐resin at pH 2–5 to form Ninhydrin‐protected Cys (Nin‐Cys) as a thiazolidine (Thz). The Thz ring, protecting both the amino and thiol groups in Nin‐Cys, completely avoids the formylation and Thz side reactions found during hydrofluoric acid (HF) cleavage when N‐π‐benzyloxymethyl histidine groups are present. Nin‐Cys is stable during coupling reactions and various cleavage conditions with trifluoroacetic acid or HF, but is deprotected under thiolytic or reducing conditions. These properties enable a facile one‐step deprotection and end‐to‐end‐cyclization reaction of Nin‐Cys peptides containing C‐terminal thioesters.
Synthesis of diketopiperazines with on‐resin N‐methylation and cyclative release
Authors: Brunel F.M. , Spatola A.F.
Published: March 2004

Abstract:  Enantiomerically pure N‐methylated diketopiperazines (DKP) can be obtained by treating a N‐methylated resin‐bound dipeptide with 20% piperidine in dimethylformamide via a process known as cyclative release. N‐methylated resin‐bound dipeptides can be formed from N‐methylated precursors or N‐methylation can be selectively performed on the resin. When on‐resin N‐methylation was performed on the C‐terminal side of the dipeptide, diastereomers were formed. Yet the cyclative release is shown to be a stereoselective process, as seen using preformed N‐methylated amino acids. The procedure was also applied to synthesize the pseudodiketopiperazine cyclo(Pheψ[CH2NH]Leu). When comparing nonmethylated, monomethylated and bismethylated derivatives, we find that N‐methylation results in a dramatic increase in solubility.
Synthesis of 9‐membered dilactams derived from 1,3‐diaminopropionic and glutamic acids
Authors: Chulin A.N. , Rodionov I.L. , Ivanov V.T.
Published: March 2004

Abstract:  Previously unknown 9‐membered bridged dipeptides derived from l or d isomers of 1,3‐diaminopropionic acids and l‐glutamic acid were synthesized using aminoacyl incorporation reaction. Key intermediates containing internal pyroglutamyl moiety were prepared via side chain to backbone cyclization of related protected dipeptide derivatives of glutamic acid.
Synthesis and activity of the melanocortin Xaa‐d‐Phe‐Arg‐Trp‐NH2 tetrapeptides with amide bond modifications
Authors: Todorovic A. , Holder J. R. , Scott J. W. , Haskell‐Luevano C.
Published: March 2004

Abstract:  The melanocortin receptor (MCR) pathway has been identified as participating in several physiologically important pathways including pigmentation, energy homeostasis, inflammation, obesity, hypertension, and sexual function. All the endogenous MCR agonists contain a core His‐Phe‐Arg‐Trp sequence identified as important for receptor molecular recognition and stimulation. Several structure–activity studies using the Ac‐His‐d‐Phe‐Arg‐Trp‐NH2 tetrapeptide template have been performed in the context of modifying N‐terminal ‘capping’ groups and amino acid constituents. Herein, we report the synthesis and pharmacologic characterization of modified Xaa‐d‐Phe‐Arg‐Trp‐NH2 (Xaa = His or Phe) melanocortin tetrapeptides (N‐site selective methylation, permethylation, or amide bond reduction) at the mouse MC1, MC3, MC4 and MC5 receptors. The modified peptides generated in this study resulted in equipotent or reduced MCR potency when compared with control ligands. The reduced amide bond analog of the Phe‐d‐Phe‐Arg‐Trp‐NH2 peptide converted its agonist activity into an antagonistic at the central mMC3 and mMC4 receptors involved in the regulation of energy homeostasis, while retaining full agonist activity at the peripheral MC1 and MC5 receptors.
Benzodioxocin‐3‐ones and N‐acyl‐3‐amino‐3‐buten‐2‐ones: novel classes of cathepsin K cysteine protease inhibitors*
Authors: Yamashita D. S. , Xie R. , Lin H. , Wang B. , Shi S. D.‐H. , Quinn C. J. , Hemling M. E. , Hissong C. , Tomaszek T. A. , Veber D. F.
Published: March 2004

Abstract:  The design, synthesis, enzymologic, and protein mass spectrometric characterization of benzodioxocin‐3‐one and N‐acyl‐3‐amino‐3‐buten‐2‐one inhibitors of the cysteine protease cathepsin K are described. The benzodioxocin‐3‐one ring system is chemically unstable giving rise to a mixture of N‐acyl‐3‐amino‐3‐buten‐2‐one and hemiketals. This mixture of N‐acyl‐3‐amino‐3‐buten‐2‐one and hemiketals potently inhibits recombinant, human cathepsin K (IC50 = 36 nM) by a time‐independent, irreversible mechanism. Formation of a covalent adduct between cathepsin K and inhibitor has been confirmed by mass spectrometry.
Conformational properties of hybrid peptides containing α‐ and ω‐amino acids*
Authors: Roy R.S. , Balaram P.
Published: March 2004

Abstract:  This review briefly surveys the conformational properties of guest ω‐amino acid residues when incorporated into host α‐peptide sequences. The results presented focus primarily on the use of β‐ and γ‐residues in αω sequences. The insertion of additional methylene groups into peptide backbones enhances the range of accessible conformations, introducing additional torsional variables. A nomenclature system, which permits ready comparisons between α‐peptides and hybrid sequences, is defined. Crystal structure determination of hybrid peptides, which adopt helical and β‐hairpin conformations permits the characterization of backbone conformational parameters for β‐ and γ‐residues inserted into regular α‐polypeptide structures. Substituted β‐ and γ‐residues are more limited in the range of accessible conformation than their unsubstituted counterparts. The achiral β,β‐disubstituted γ‐amino acid, gabapentin, is an example of a stereochemically constrained residue in which the torsion angles about the Cβ–Cγ (θ1) and Cα–Cβ (θ2) bonds are restricted to the gauche conformation. Hybrid sequences permit the design of novel hydrogen bonded rings in peptide structures.
Biological activity of silylated amino acid containing substance P analogues
Authors: Cavelier F. , Marchand D. , Martinez J. , Sagan S.
Published: March 2004

Abstract:  The need to replace natural amino acids in peptides with nonproteinogenic counterparts to obtain new medicinal agents has stimulated a great deal of innovation on synthetic methods. Here, we report the incorporation of non‐natural silylated amino acids in substance P (SP), the binding affinity for the two hNK‐1 binding sites and, the potency to stimulate phospholipase C (PLC) and adenylate cyclase of the resulting peptide. We also assess the improvement of their stability towards enzyme degradation. Altogether, we found that replacing glycine with silaproline (Sip) in position 9 of SP leads to a potent analogue exhibiting an increased resistance to angiotensin‐converting enzyme hydrolysis.
Effects of glycaemic control on cardiovascular disease in diabetic American Indians: the Strong Heart Study
Authors: Lu W. Q. , Resnick H. E. , Jablonski K. A. , Jain A. K. , Jones K. L. , Robbins D. C. , Howard B. V.
Published: March 2004

Aims  Diabetes increases the risk of cardiovascular disease (CVD). Only part of this excess risk is explained by diabetes‐associated hypertension, obesity, and lipid disorders. Poor glycaemic control may help explain the residual CVD risk. The aim of this study was to determine whether variations in glycaemic control are associated with CVD risk in diabetic individuals.

Methods  We examined longitudinal data from the Strong Heart Study, a population‐based study of CVD and its risk factors among American Indians (a population with a high prevalence of diabetes). Diabetes was defined using the 1998 World Health Organization criteria: fasting plasma glucose ≥ 126 mg/dl or 2‐h plasma glucose ≥ 200 mg/dl. American Diabetes Association guidelines for glycaemic control were used: good, A1c < 7%; fair, 7–7.9%; and poor, ≥ 8%. The analysis was based on data from diabetic individuals with no CVD at baseline.

Results  During 9 years of follow‐up, 494 of the 2011 diabetic participants developed CVD. Although Cox multivariate regression modelling showed dose–response effects of glycaemic control on overall CVD and coronary heart disease (CHD) incidence, the relationships were weakened when adjusted for confounding variables. Kaplan–Meier analysis, however, showed that diabetic individuals with poor baseline glycaemic control had significantly increased proportions of overall CVD and CHD (P = 0.001) during the 9 years of follow‐up, compared with those who had good or fair control.

Conclusion  These findings highlight the importance of risk factors, such as high blood pressure and dyslipidaemia, in increasing CVD risk in those with diabetes.
Combination therapy for Type 2 diabetes: repaglinide plus rosiglitazone
Authors: Raskin P. , McGill J. , Saad M. F. , Cappleman J. M. , Kaye W. , Khutoryansky N. , Hale P. M.
Published: March 2004

Aims  This 24‐week, randomized, multicentre, open‐label, parallel‐group clinical trial compared efficacy and safety of repaglinide monotherapy, rosiglitazone monotherapy, and combination therapy (repaglinide plus rosiglitazone) in Type 2 diabetes after unsatisfactory response to sulphonylurea or metformin monotherapy.

Methods  Enrolled patients (n = 252) were adults having Type 2 diabetes for at least 1 year, with HbA1c values > 7.0% after previous monotherapy (sulphonylurea or metformin, ≥ 50% maximal dose). Prior therapy was withdrawn for 2 weeks, followed by randomization to repaglinide, rosiglitazone, or repaglinide/rosiglitazone. Study treatments were initiated with a 12‐week dose optimization period (doses optimized according to labelling), followed by a 12‐week maintenance period. Efficacy endpoints were changes in HbA1c values (primary) or fasting plasma glucose values (secondary).

Results  Baseline HbA1c values were comparable (9.3% for repaglinide, 9.0% for rosiglitazone, 9.1% for combination). Mean changes in HbA1c values at the end of treatment were greater for repaglinide/rosiglitazone therapy (−1.43%) than for repaglinide (−0.17%) or rosiglitazone (−0.56%) monotherapy. Reductions of fasting plasma glucose values were also greater for combination therapy (−5.2 mmol/l, −94 mg/dl) than for repaglinide monotherapy (−3.0 mmol/l, −54 mg/dl) or rosiglitazone monotherapy (−3.7 mmol/l, −67 mg/dl). Minor hypoglycaemic events occurred in 9% of combination therapy patients, vs. 6% for repaglinide and 2% for rosiglitazone. Individual weight gains for combination therapy were correlated to HbA1c response.

Conclusions  The combination therapy regimen was well tolerated. In patients previously showing unsatisfactory response to oral monotherapy, glycaemic reductions were greater for the repaglinide/rosiglitazone combination regimen than for use of either repaglinide or rosiglitazone alone.
C‐reactive protein and risk factors for peripheral vascular disease in subjects with Type 2 diabetes mellitus
Authors: Yu H‐I. , Sheu W. H‐H. , Song Y‐M. , Liu H‐C. , Lee W‐J. , Chen Y‐T.
Published: March 2004

Aims  To compare the importance of different inflammatory markers and traditional risk factors in predicting peripheral vascular disease (PVD) in patients with Type 2 diabetes mellitus.

Methods  A cross‐sectional analysis of 30 Type 2 diabetic patients with PVD defined by ankle‐brachial index (ABI) < 0.9, and 60 Type 2 diabetic patients without PVD (ABI > 1.0). Overnight blood was drawn and sent for study.

Results  Longer diabetic duration (15 ± 8 vs. 10 ± 7 years, P = 0.007), higher serum creatinine level (0.11 ± 0.04 vs. 0.09 ± 0.03 mmol/l, P = 0.001), higher total cholesterol/high‐density lipoprotein‐cholesterol (TC/HDL‐C) ratio (5.2 ± 1.6 vs. 4.3 ± 1.1, P = 0.004) and increased hypertension status (70% vs. 52%, P = 0.014) and cerebral infarction (CI) history (23% vs. 3%, P = 0.009) were noted in Type 2 diabetes with PVD. Those with PVD also showed significantly higher serum levels of C‐reactive protein (CRP) (median 0.282 vs. 0.102 mg/dl, P < 0.001) and interleukin (IL)‐6 (10.6 ± 1.81 vs 1.6 ± 4.6 pg/ml, P = 0.001). Multivariate regression analysis showed that higher serum levels of C‐reactive protein (CRP), longer diabetic duration, and use of angiotensin converting enzyme inhibitor (ACEI) were independently associated with PVD in Type 2 diabetes mellitus.

Conclusions  Type 2 diabetic patients with PVD had longer diabetic duration, higher serum creatinine levels, higher TC/HDL‐C ratio, higher hypertension and CI history and higher CRP and IL‐6 levels. Only serum CRP level, diabetic duration, and use of ACEI were independently associated with PVD in Type 2 diabetes mellitus.
Detecting silent coronary stenoses and stratifying cardiac risk in patients with diabetes: ECG stress test or exercise myocardial scintigraphy?
Authors: Cosson E. , Paycha F. , Paries J. , Cattan S. , Ramadan A. , Meddah D. , Attali J‐R. , Valensi P.
Published: March 2004

Aims  To determine whether performing a myocardial scintigraphy immediately after a maximal electrocardiogram (ECG) stress test is effective in detecting silent coronary stenoses and predicting cardiovascular events.

Methods  Asymptomatic patients (n = 262) aged 57.6 ± 8.8 years, with diabetes for 12.0 years (5–39) [median (range)] and no history of a cardiac event, underwent a maximal ECG stress test followed by a myocardial scintigraphy. The patients with an abnormal ECG stress test or abnormal imaging underwent a coronary angiography. Cardiac events were assessed in 250 (95.4%) patients followed for 37.8 months (3–101).

Results  The ECG stress test was abnormal in 54 patients. Among them, 18 had coronary stenoses and seven had a cardiac event. Despite a normal ECG stress test, the myocardial scintigraphy was abnormal in 42 additional patients, including 16 patients with coronary stenoses. Four of these 42 patients experienced a cardiac event. Follow‐up showed a poor prognosis in subjects who were abnormal on the two tests. Univariate predictors of the 15 cardiac events were the ECG stress test [odds ratio (OR) 3.9, 95% confidence interval (CI) 1.3, 11.4, P = 0.008], myocardial scintigraphy (OR 3.8, 95% CI 1.3, 11.0, P = 0.009), coronary stenoses (OR 26.6, 95% CI 7.6, 90.7, P < 0.001), and peripheral or carotid occlusive arterial disease (OR 9.5, 95% CI 2.1, 42.5, P < 0.001).

Conclusions  In the asymptomatic patients with diabetes, combining a myocardial scintigraphy with a maximal ECG stress test is effective in detecting more patients with coronary stenoses and predicting cardiovascular events. However, the ECG stress test has a good negative predictive value for cardiac events (97%), is cheaper, and should therefore be proposed first.
The associations of body mass index, C‐peptide and metabolic status in Chinese Type 2 diabetic patients
Authors: Chan W. B. , Tong P. C. Y. , Chow C. C. , So W. Y. , Ng M. C. Y. , Ma R. C. W. , Osaki R. , Cockram C. S. , Chan J. C. N.
Published: March 2004

Background  Chinese Type 2 diabetic subjects are generally less obese than their Caucasian counterparts. We hypothesized that lean and obese Chinese Type 2 diabetic subjects have different metabolic and insulin secretory profiles. We compared the clinical features, C peptide and metabolic status between lean/normal weight and obese diabetic subjects.

Study design  We conducted a cross‐sectional study on 521 consecutive diabetic subjects newly referred to a Diabetes Clinic in 1996. The subjects were categorized into underweight (< 18.5 kg/m2), normal weight (18.5–23 kg/m2) and overweight (≥ 23 kg/m2) according to the re‐defined WHO criterion for obesity in Asia Pacific Region. Metabolic and anthropometric parameters were compared between groups with different levels of obesity.

Results  In this cohort, 5.8, 30.6 and 63.7% of subjects were underweight, normal weight and overweight, respectively, using the ‘Asian’ criteria. Of these 521 subjects, 20% had fasting C‐peptide less than 0.2 nmol/l, suggesting insulin deficiency. Fasting C‐peptide showed linear increasing trend (P < 0.001) while HbA1c showed decreasing trend (P = 0.001) with BMI after adjustment for duration of disease. There were more subjects in the underweight group who were treated with insulin (41.3% vs. 13.9 and 8.2%, P < 0.001). Although homeostasis model assessment was similar amongst the three groups, systolic (P = 0.006) and diastolic blood pressure (P < 0.001) and triglyceride (P < 0.001) showed increasing, while HDL‐C (P < 0.001) showed decreasing, trends across different BMI groups. The underweight patients had the lowest C‐peptide and highest HbA1c while overweight patients had the highest C‐peptide, blood pressure, triglyceride but lowest HbA1c levels.

Conclusion  In Chinese Type 2 diabetic patients, lean subjects had predominant insulin deficiency and obese subjects had features of metabolic syndrome. Clinicians should have low threshold to initiate insulin therapy in lean Type 2 diabetic patients with suboptimal glycaemic control. In obese diabetic patients, aggressive control of multiple cardiovascular risks is of particular importance.
Prevalence and risk factors for diabetes in Ho Chi Minh City, Vietnam
Authors: Duc Son L. E. N. T. , Kusama K. , Hung N. T. K. , Loan T. T. H. , Van Chuyen N. , Kunii D. , Sakai T. , Yamamoto S.
Published: March 2004

Aims  To determine the prevalence of diabetes and associated risk factors in Ho Chi Minh City, Vietnam.

Methods  A total of 2932 participants aged 15 and above in Ho Chi Minh City were screened for diabetes in a cross‐sectional study. The study was conducted from March–May 2001. Demographic, occupation, anthropometry and blood pressure were recorded. Blood glucose was calculated on fasting capillary and venous blood. The classification of diabetes and impaired fasting glucose (IFG) was carried out according to WHO and American Diabetes Association criteria.

Results  The crude prevalence of diabetes and IFG were 6.6 and 3.2%, respectively. After age, sex‐adjustment to the Vietnam population census, the prevalence was 3.8 and 2.5%, respectively; approximately 40% of cases were found to be newly diagnosed diabetes. The crude prevalence of diabetes in the urban area was approximately 2.8 times higher than that recorded in the 1993 study (6.9 vs. 2.5%, respectively). In this study, there was a positive association between diabetes and sex, age, overweight, waist hip ratio (WHR), and having a history of delivering large for gestational age child; there was a negative association between diabetes and physical activity and occupation.

Conclusions  This study found that the age, sex‐adjusted prevalence of diabetes and IFG in Ho Chi Minh City were 3.8 and 2.5%, respectively, a rapid increase in the recent decade. Our study also indicates that ageing, a high WHR level, overweight and a sedentary lifestyle may be important determinants of the increased prevalence of diabetes during this transition period in Vietnam.
Impaired fasting glycaemia resembles impaired glucose tolerance with regard to cardiovascular risk factors: population‐based, cross‐sectional study of risk factors for cardiovascular disease
Authors: Heldgaard P. E. , Olivarius N. de. F. , Hindsberger C. , Henriksen J. E.
Published: March 2004

Aims  To compare subjects with impaired glucose tolerance and impaired fasting glucose in relation to risk factors for developing cardiovascular disease.

Methods  A total of 1374 patients (678 female, 696 male) listed with a general practice clinic in Denmark were given an oral glucose tolerance test, a physical examination, and a self‐administered questionnaire. Risk factors for cardiovascular disease were assessed for 90 participants (48 female, 42 male) with impaired glucose tolerance (including 12 subjects (1 female and 11 male), who also fulfilled criteria for impaired fasting glycaemia) and 51 subjects (20 female, 31 male) with impaired fasting glycaemia (World Health Organization 1999 criteria).

Results  There were no statistical differences with regard to known risk factors for cardiovascular disease between participants with isolated impaired fasting glycaemia and those with impaired glucose tolerance.

Conclusions  We found noticeable similarities in the cardiovascular risk factor profile in subjects with impaired fasting glycaemia and in subjects with impaired glucose tolerance in our population. When planning screening initiatives, it seems relevant to take into account people with impaired fasting glycaemia as well as those with impaired glucose tolerance.
Unreliable estimation of HbA1c due to the presence of Camperdown haemoglobin [β 104 (G6) Arg → Ser]
Authors: Castelli R. , Tempesta A. , Bianchi A. , Porro T. , Ivaldi G. , Cappellini M. D.
Published: March 2004

Aims  To suggest the possible unreliability of HbA1c determination in presence of haemoglobin variants during routine metabolic evaluation.

Methods  We present a case of Camperdown haemoglobin, accidentally detected in a middle‐aged Italian man during routine metabolic evaluation for newly diagnosed diabetes. The haemoglobin variant has been identified by exchange high performance liquid chromatography (CE‐HPLC) (VARIANT™ HbA1c Program, Bio‐Rad Laboratories, Hercules, CA, USA), and characterized at molecular level by direct sequencing.

Results  A 56‐year‐old male of Northern Italian origin, presented to our centre for a Type 2 diabetes mellitus of recent diagnosis. HbA1c determination was routinely determinated. The patient's chromatogram showed an inappropriate peak of 38.5% in the HbA1c position suggestive for the presence of abnormal haemoglobin. Further evaluation identified an abnormal haemoglobin peak even higher (49.5%) eluting at 1.34 minutes in P2‐window. Molecular characterization of the mutation showed a nucleotide replacement, AGG → AGC at codon 104, causing the amino acid replacement Arg → Ser at position 104 (G6) that give rise to Hb Camperdown.

Conclusions  Haemoglobinopathies can lead to inaccurate glycated haemoglobin level determination. In patients carrying haemoglobin variants, the different methods for determinations of glycated haemoglobin could result in different errors, showing either higher or lower values than expected.
Severe hypertriglyceridaemia in diabetic ketoacidosis: clinical and genetic study
Authors: Karagianni C. , Stabouli S. , Roumeliotou K. , Traeger‐Synodinos J. , Kavazarakis E. , Gourgiotis D. , Lambrou J. , Kanavakis E.
Published: March 2004

The lipoprotein lipase coding gene sequence was analysed on a 10‐year‐old girl with new‐onset Type 1 diabetes mellitus (DM), ketoacidosis and severe hypertriglyceridaemia (TG > 112.9 mmol/l), revealing that the patient was a compound heterozygote for two mutations, D9N in exon 2 and S447X in exon 9. Although these two mutations usually do not considerably impair lipolytic enzyme activity, the combination of both in this patient may play a role in the development of severe hypertriglyceridaemia.
Hypoadiponectinaemia in South Asian women during pregnancy: evidence of ethnic variation in adiponectin concentration
Authors: Retnakaran R. , Hanley A. J. G. , Raif N. , Connelly P. W. , Sermer M. , Zinman B.
Published: March 2004

Aims  People of South Asian descent face an increased risk of Type 2 diabetes mellitus (DM) and coronary artery disease (CAD) compared with other ethnic groups. One candidate factor underlying this risk may be adiponectin, as circulating levels of this adipocyte‐derived protein are reduced in both Type 2 DM and CAD. In a recent study, we assessed the relationship between adiponectin and gestational diabetes (GDM), a potential model of early events in the natural history of Type 2 DM. Here, we report the impact of ethnicity on plasma adiponectin concentration in that study.

Methods  A cross‐sectional study was performed in 180 women undergoing oral glucose tolerance testing in late second or early third trimester to investigate the relationship between adiponectin and glucose tolerance in pregnancy. Based on self‐reported ethnicity, participants were stratified into three groups: (i) Caucasian (n = 116), (ii) South Asian (n = 31), and (iii) Asian (n = 28).

Results  Median adiponectin concentration was much lower in the South Asian group (9.7 µg/ml) than in Caucasians (15.8 µg/ml) or Asians (16.1 µg/ml) (overall P < 0.0001). With adjustment for age, prepregnancy body mass index, weight gain in pregnancy, previous history of GDM, family history of DM, fasting insulin and glucose intolerance, mean adiponectin remained significantly lower among South Asians compared with either Caucasians (P < 0.0001) or Asians (P = 0.0034).

Conclusions  Women of South Asian descent exhibit significantly reduced plasma concentrations of adiponectin in pregnancy compared with Caucasian and Asian counterparts. This observation raises the possibility of hypoadiponectinaemia as a potential factor contributing to the increased risk of diabetes and cardiovascular disease in South Asians.
Towards the development of a transferable set of value estimates for environmental attributes
Authors: Van Bueren Martin , Bennett Jeff
Published: March 2004

Estimates of environmental values are frequently required as inputs to cost‐benefit analyses when evaluating alternative options for managing natural resources. One strategy to avoid the high cost of conducting empirical work when non‐market values are involved is to use value estimates from an existing source study and to transfer them to the target context of interest (a practice known as benefit transfer). However, the transfer of values is subject to a host of potential errors and could lead to significant overestimation or underestimation of welfare change. The present paper reports the results of a choice modelling study in which household values for the impacts of land and water degradation in Australia are estimated. A key objective of the present study was to test the validity of transferring estimates derived in a national context to different regional contexts. On the basis of these test results, inferences are made about the impact that differing contexts have on value estimates. The scale of value differences across the different contexts provides a guide for calibrating benefit transfer estimates.
Levy‐funded research choices by producers and society
Authors: Alston Julian M. , Freebairn John W. , James Jennifer S.
Published: March 2004

Commodity levies are used increasingly to fund producer collective goods such as research and promotion. In the present paper we examine theoretical relationships between producer and national benefits from levy‐funded research, and consider the implications for the appropriate rates of matching government grants, applied with a view to achieving a closer match between producer and national interests. In many cases the producer and national optima coincide. First, regardless of the form of the supply shift, when product demand is perfectly elastic, or all the product is exported, domestic benefits and costs of levy‐funded research all go to producers and they have appropriate incentives. Second, if research causes a parallel supply shift, the producer share of research benefits is the same as their share of costs of a levy, and their incentives are compatible with national interests. In such cases, a matching grant would cause an over‐investment in research from a national perspective. However, if demand is less than perfectly elastic, and research causes a pivotal supply shift, the producer share of benefits is smaller than their share of costs of the levy, and they will under‐invest in research from a national point of view. A matching grant can be justified in such cases, however the magnitude of the optimal grant is sensitive to market conditions.
Gendered Identities in the Work of Overseas Tour Reps
Authors: Guerrier Yvonne , Adib Amel
Published: March 2004

Gender construction within the tourism and leisure industry is under‐researched. In this article, we draw on empirical research on overseas tour reps to consider the ways in which men and women working alongside each other in the same feminized role ‘do gender’. In particular we explore how these workers deal with the particular dilemmas of the sexualization of women at work and the men reps’ potential threat to their heterosexuality, in a role where the boundaries between work and play are ambiguous. We argue that reps reveal masculinities and femininities that comply with traditional expectations. Young men reps are portrayed in ‘laddish’ terms in relation to their engagement with alcohol and sexual relationships with guests. Women reps emphasize their role as providers of emotional labour and taking control of guests’ perceptions and report refraining from sexual relationships with guests. Even within the same work role in this case study, men and women appear to construct different work identities.
Post‐stroke pain case study: clinical characteristics, therapeutic options and long‐term follow‐up
Authors: Hansson P.
Published: March 2004

Central post‐stroke pain (CPSP) is a syndrome characterized by sensory disturbances and neuropathic pain. In 40%−60% of CPSP patients, the onset of central pain following a stroke occurs more than 1 month after the stroke, creating a source of diagnostic uncertainty or significant delay in treatment since healthcare providers familiar with CPSP may no longer be caring for the patient when the symptoms occur. In addition to chronic pain, the presence of somatosensory abnormalities is the most important diagnostic corollary of CPSP. Neuropathic or central pain has been estimated to occur in up to 8% of patients after a stroke, and about 18% of stroke patients with a somatosensory disturbance will develop CPSP. Although largely a matter of conjecture, it is generally agreed that damage to spinothalamic sensory pathways plays a significant role in the pathogenesis of CPSP. A comprehensive examination of the patient for sensory deficits is essential before treatment can be initiated. Functional disturbances such as depression, anxiety and sleep disturbances are significant comorbid conditions associated with CPSP; the physician should incorporate an assessment of these potential comorbidities into the examination. Treatment options for CPSP are limited; at present, amitriptyline is the drug of first choice. Other drugs including antidepressants, anticonvulsants, antiarrhythmics, opioids and N‐methyl‐d‐aspartate antagonists may provide relief for some patients who do not respond to amitriptyline. Included in this review is a case study outlining the challenges of managing the patient with CPSP.
Pain in diabetic neuropathy case study: whole patient management
Authors: Marchettini P. , Teloni L. , Formaglio F. , Lacerenza M.
Published: March 2004

Painful diabetic peripheral neuropathy (DPN) is described as a superficial burning pain associated with other positive and/or negative sensory systems affecting the feet and lower extremities. It is one of the most commonly encountered neuropathic pain syndromes in clinical practice. Presentation may be complicated by multiple symptoms, including allodynia, hyperalgesia, other less well characterized dysesthesias, and serious disruption of social functioning and mood. Peripheral nerve function may deteriorate, which can account for patient reports of diminution of pain after several years of follow‐up. Although current understanding holds that the pathogenesis of DPN is multifactorial in nature, long‐term studies have shown that rigorous glycemic control is the most relevant factor in clinical intervention and can delay the onset and slow the progression of neuropathy. In addition to glycemic control, other treatment approaches must be examined in order to restore quality of life for patients experiencing painful DPN. Differential diagnosis is required to isolate DPN from other unexplained chronic pain. Neurologic testing in painful DPN is an area of active research and is used to assess the neurologic pathways giving rise to the pain, the degree of neural damage and the degree of subclinical damage. Current treatment options for DPN include mainly antidepressants and anticonvulsants, with other agents such as tramadol, dextromethorphan and memantine being employed or studied. This review article includes a case study of a patient with painful DPN to demonstrate the current management strategies for this neuropathic pain syndrome.
Accelerating aging by mouse reverse genetics: a rational approach to understanding longevity
Authors: Hasty Paul , Vijg Jan
Published: March 2004

Investigating the molecular basis of aging has been difficult, primarily owing to the pleiotropic and segmental nature of the aging phenotype. There are many often interacting symptoms of aging, some of which are obvious and appear to be common to every aged individual, whereas others affect only a subset of the elderly population. Although at first sight this would suggest multiple molecular mechanisms of aging, there now appears to be almost universal consensus that aging is ultimately the result of the accumulation of somatic damage in cellular macromolecules, with reactive oxygen species likely to be the main damage‐inducing agent. What remains significant is unravelling how such damage can give rise to the large variety of aging symptoms and how these can be controlled. Although humans, with over a century of clinical observations, remain the obvious target of study, the mouse, with a relatively short lifespan, easy genetic accessibility and close relatedness to humans, is the tool par excellence to model aging‐related phenotypes and test strategies of intervention. Here we present the argument that mouse models with engineered defects in genome maintenance systems are especially important because they often exhibit a premature appearance of aging symptoms. Confirming studies on human segmental progeroid syndromes, most of which are based on heritable mutations in genes involved in genome maintenance, the results thus far obtained with mouse models strongly suggest that lifespan and onset of aging are directly related to the quality of DNA metabolism. This may be in keeping with the recent discovery of a possible ‘universal survival’ pathway that improves antioxidant defence and genome maintenance and simultaneously extends lifespan in the mouse and several invertebrate species.
Lung fractional moving blood volume in normally grown and growth restricted foetuses
Authors: Hernandez‐Andrade Edgar , Thuring‐Jönsson Ann , Jansson Tomas , Lingman Göran , Maršàl Karel
Published: March 2004

Objective:  To examine foetal lung blood perfusion using power Doppler ultrasound (PDU) and to compare fractional moving blood volume (FMBV) and mean pixel intensity (MPI) estimations in the lungs of normally grown (NG) foetuses and foetuses with intrauterine growth restriction (IUGR) and also to correlate foetal lung FMBV and MPI with respiratory complications after birth.

Methods:  Lungs of 47 NG and 25 IUGR foetuses after 32 weeks of gestation were examined with PDU. FMBV and MPI were estimated in a defined region in the posterior part of the foetal lung closest to maternal abdominal wall. FMBV and MPI were correlated to foetal weight deviation and gestational age. Perinatal outcome and respiratory complications after birth were recorded in both groups.

Results:  There were significantly lower FMBV and MPI values in IUGR than in NG foetuses. The overall variation was lower for FMBV than for MPI. There was a slightly higher correlation between FMBV and foetal weight deviation [r = 0·33, 95% confidence intervals (CI) 0·11–0·52] than between MPI and foetal weight deviation (r = 0·26, 95% CI 0·03–0·46). There was no significant correlation between FMBV or MPI and gestational age. No differences between the groups were found in the rate of respiratory complications, and they were not correlated either to the FMBV or MPI.

Conclusion:  FMBV and MPI, estimated from the PDU signals of foetal lung circulation, showed lower values in third‐trimester pregnancies complicated by IUGR. The frequency of neonatal respiratory complications was not increased in cases with low pulmonary FMBV and MPI values.