bluuebunny/crossref_metadata_2025 huggingface dataset:
Charge Transfer of N2+ and O2+ with Sodium Atoms
Authors: Henderson W. R. , Mentall J. E. , Fite W. L.
Published: January 2005

Collisions of nitrogen and oxygen molecular ions with atomic sodium have been examined in a crossed-beam experiment in which the ion energy range was from 25 to 200 eV. It was found that charge transfer occurs with cross sections in excess of 10−16 cm2 and that in both cases the energy dependence is that typical of accidental resonance charge transfer. Extrapolation of these cross sections to the thermal energy range suggests that the thermal-energy charge-transfer rates are about 5×10−11 cm3/sec with N2+ and about 8×10−11 cm3/sec for O2+.
Kinetic Theory of Dense Fluid Mixtures. III. The Doublet Distribution Functions of the Rice—Allnatt Model
Authors: Wei Ching Cheng , Davis H. Ted
Published: January 2005

The doublet distribution functions are obtained by solving the Rice—Allnatt equations for binary dense fluid mixtures. With the doublet distribution functions and the singlet distribution functions obtained in this article and a previous article of the same series, explicit expressions for all the transport coefficients of binary dense fluid mixtures are derived. A comparison of our results with the original Rice—Allnatt results, which differ somewhat from ours, and with experimental data is given, and the correspondence between our results and those of some other kinetic theories is discussed.
Electric Dipole Moment of the n—π* Singlet State of HCOF
Authors: Lombardi John R. , Campbell David , Klemperer William
Published: January 2005

Stark-effect measurements of the 2480 Å band of formyl fluoride have been made. The dipole components are μa′=+1.65±0.1 D and |μb|=2.0(+0.5 or −1.0) D. The sign of μa′ is the same as that of μa″, in disagreement with a picture of excitation localized in the carbonyl group.
Proton Relaxation in Potassium—Ammonia Solutions
Authors: Newmark R. A. , Stephenson J. C. , Waugh J. S.
Published: January 2005

The spin—lattice relaxation time, T1, for protons in potassium—liquid-ammonia solutions has been determined over a wide range of concentrations (2×10−4M to 3M) and temperatures (−74° to +21°C). T1−1 for pure ammonia was determined over the same temperature range and found proportional to the viscosity divided by the temperature. The relaxation rate due to the paramagnetic electrons, 1/T1K, rises with increasing potassium concentration to a maximum at about 0.15M, then decreases as the concentration is increased further. We have determined that the electron correlation time is about 4×10−13 sec up to the 1/T1K maximum and then decreases rapidly at higher potassium concentrations.
Energy Levels of Ho3+ in LaCl3
Authors: Rajnak Katheryn , Krupke William F.
Published: January 2005

A least-squares fit of the previously assigned J levels of Ho3+ in LaCl3 combined with a crystal-field calculation for the upper levels has made possible the assignment of many of the levels above 28 000 cm−1 observed by Dieke and Pandey. A final least-squares fit of 23 J levels, with the inclusion of configuration interaction, gave an rms deviation of 68 cm−1 with the parameter values E0=20 770, E1=6682.6, E2=30.69, E3=620.1, ζ=2127.1, α=23.5, β=−811.2 cm−1. The crystal-field parameters resulting from a fit of 81 components of the 5I4,5,6,7,8 and 5F2,3,4,5 levels are B20=113.6, B40=−33.9, B60=−27.8, and B66=276.7 cm−1. The rms deviation in this case was 2.0 cm−1. These crystal-field parameters give a satisfactory prediction of the crystal-field splitting of most of the excited J levels.
On Symmetry-Breaking Instabilities in Dissipative Systems
Authors: Prigogine I. , Nicolis G.
Published: January 2005

The theory of hydrodynamic instability has always been an important part of fluid dynamics [see, e.g., Chandrasekhar, in Hydrodynamic and Hydromagnetic Stability (Clarendon Press, Oxford, England, 1961) and Non-Equilibrium Thermodynamics, Variation Techniques, and Stability, R. J. Donnelly, R. Herman, and I. Prigogine, Eds. (University of Chicago Press, Chicago, Ill., 1966)]. Such instabilities involve both convective processes (such as mechanical flow) and dissipative processes (such as viscous dissipation). We investigate the possibility of an instability in purely dissipative systems involving chemical reactions and transport processes such as diffusion, but no hydrodynamic motion. We demonstrate that for well-defined values of the constraints such as the chemical affinities of the over-all reactions and the constants involved, such systems can indeed become unstable. Such an instability is investigated following an example of autocatalytic reactions first proposed by Turing. The major feature of this instability is its symmetry breaking character. Indeed, beyond the transition point the stable steady state is inhomogenous, the diffusion compensating the differences in reaction rates. The existence of such instabilities has far-reaching consequences which are briefly discussed.
Accurate Single-Center Expansions with Slater-Type Orbitals: Hydrogen Atom and Hydrogen Molecule—Ion
Authors: Hayes Edward F. , Parr Robert G.
Published: January 2005

Single-center wavefunctions are determined for the off-center hydrogen atom, using Slater orbitals of integral quantum number and variable orbital exponent. With the proton situated a distance R from the expansion point, for R=0.6, 1.0, 1.4, and 1.8 bohr, the approximate energies obtained are 0.49961, 0.49951, 0.49929, and 0.49913 a.u. A single-center wavefunction is given for the 1sσg state of H2+ for the internuclear separation 2.0 bohr. The energy of this function is within 2×10−4 a.u. of the exact result. Here the earlier work of Joy and Handler has been extended by including spherical harmonics with l up to 22 and by reducing the number of nonlinear variational parameters through the rule that the high-l orbitals peak at the protons. Wavefunctions also are presented for the 1sσg and 2pσu states for an internuclear separation of 3.6 bohr. For all of the states considered, the Joy—Handler convergence rule that the energy increment for high l is inversely proportional to l4 is verified, and extrapolations made. For the hydrogen atom, this increment also is found to be proportional to R3. By calculations of the dipole moment of the hydrogen-atom functions and by detailed examination of the l=0 component of these functions, it is shown that the lower-l components in single-center wavefunctions are more sensitive to the presence of higher-l components than had earlier been thought.
Second-Order Density Matrix for a Spin-Projected Single Determinant
Authors: Hardisson Arturo , Harriman John E.
Published: January 2005

We have obtained the irreducible tensorial components of the second-order density matrix corresponding to a spin-projected, single-determinantal function. The results are applicable to projected-unrestricted or spin-extended SCF functions. The natural basis set for the problem is provided by the eigenfunctions of the first-order charge density matrix.
A simple test of expected utility theory using professional traders
Authors: List John A. , Haigh Michael S.
Published: January 2005

We compare behavior across students and professional traders from the Chicago Board of Trade in a classic Allais paradox experiment. Our experiment tests whether independence, a necessary condition in expected utility theory, is systematically violated. We find that both students and professionals exhibit some behavior consistent with the Allais paradox, but the data pattern does suggest that the trader population falls prey to the Allais paradox less frequently than the student population.
Enhanced
in vivo
fitness of fluoroquinolone-resistant
Campylobacter jejuni
in the absence of antibiotic selection pressure
Authors: Luo Naidan , Pereira Sonia , Sahin Orhan , Lin Jun , Huang Shouxiong , Michel Linda , Zhang Qijing
Published: January 2005

Campylobacter jejuni
, a major foodborne human pathogen, has become increasingly resistant to fluoroquinolone (FQ) antimicrobials. By using clonally related isolates and genetically defined mutants, we determined the fitness of FQ-resistant
Campylobacter
in chicken (a natural host and a major reservoir for
C. jejuni
) in the absence of antibiotic selection pressure. When monoinoculated into the host, FQ-resistant and FQ-susceptible
Campylobacter
displayed similar levels of colonization and persistence in the absence of FQ antimicrobials. The prolonged colonization in chickens did not result in loss of the FQ resistance and the resistance-conferring point mutation (C257 → T) in the
gyrA
gene. Strikingly, when coinoculated into chickens, the FQ-resistant
Campylobacter
isolates outcompeted the majority of the FQ-susceptible strains, indicating that the resistant
Campylobacter
was biologically fit in the chicken host. The fitness advantage was not due to compensatory mutations in the genes targeted by FQ and was linked directly to the single point mutation in
gyrA
, which confers on
Campylobacter
a high-level resistance to FQ antimicrobials. In certain genetic backgrounds, the same point mutation entailed a biological cost on
Campylobacter
, as evidenced by its inability to compete with the FQ-susceptible
Campylobacter
. These findings provide a previously undescribed demonstration of the profound effect of a resistance-conferring point mutation in
gyrA
on the fitness of a major foodborne pathogen in its natural host and suggest that the rapid emergence of FQ-resistant
Campylobacter
on a worldwide scale may be attributable partly to the enhanced fitness of the FQ-resistant isolates.
The Roles of Versican V1 and V2 Isoforms in Cell Proliferation and Apoptosis
Authors: Sheng Wang , Wang Guizhi , Wang Yelina , Liang Jiyong , Wen Jianping , Zheng Peng-Sheng , Wu Yaojiong , Lee Vivian , Slingerland Joyce , Dumont Dan , Yang Burton B.
Published: January 2005

Versican is a large chondroitin sulfate proteoglycan belonging to the lectican family. Alternative splicing of versican generates at least four isoforms named V0, V1, V2, and V3. We have shown that the versican V1 isoform not only enhanced cell proliferation, but also modulated cell cycle progression and protected the cells from apoptosis. Futhermore, the V1 isoform was able to not only activate proto-oncogene EGFR expression and modulate its downstream signaling pathway, but also induce p27 degradation and enhance CDK2 kinase activity. As well, the V1 isoform down-regulated the expression of the proapoptotic protein Bad. By contrast, the V2 isoform exhibited opposite biological activities by inhibiting cell proliferation and down-regulated the expression of EGFR and cyclin A. Furthermore, V2 did not contribute apoptotic resistance to the cells. In light of these results, we are reporting opposite functions for the two versican isoforms whose expression is differentially regulated. Our studies suggest that the roles of these two isoforms are associated with the subdomains CSβ and CSα, respectively. These results were confirmed by silencing the expression of versican V1 with small interfering RNA (siRNA), which abolished V1-enhanced cell proliferation and V1-induced reduction of apoptosis.
Tracking Retrograde Flow in Keratocytes: News from the Front
Authors: Vallotton Pascal , Danuser Gaudenz , Bohnet Sophie , Meister Jean-Jacques , Verkhovsky Alexander B.
Published: January 2005

Actin assembly at the leading edge of the cell is believed to drive protrusion, whereas membrane resistance and contractile forces result in retrograde flow of the assembled actin network away from the edge. Thus, cell motion and shape changes are expected to depend on the balance of actin assembly and retrograde flow. This idea, however, has been undermined by the reported absence of flow in one of the most spectacular models of cell locomotion, fish epidermal keratocytes. Here, we use enhanced phase contrast and fluorescent speckle microscopy and particle tracking to analyze the motion of the actin network in keratocyte lamellipodia. We have detected retrograde flow throughout the lamellipodium at velocities of 1–3 μm/min and analyzed its organization and relation to the cell motion during both unobstructed, persistent migration and events of cell collision. Freely moving cells exhibited a graded flow velocity increasing toward the sides of the lamellipodium. In colliding cells, the velocity decreased markedly at the site of collision, with striking alteration of flow in other lamellipodium regions. Our findings support the universality of the flow phenomenon and indicate that the maintenance of keratocyte shape during locomotion depends on the regulation of both retrograde flow and actin polymerization.
Three-dimensional Ultrastructure ofSaccharomyces cerevisiaeMeiotic Spindles
Authors: Winey Mark , Morgan Garry P. , Straight Paul D. , Giddings Thomas H. , Mastronarde David N.
Published: January 2005

Meiotic chromosome segregation leads to the production of haploid germ cells. During meiosis I (MI), the paired homologous chromosomes are separated. Meiosis II (MII) segregation leads to the separation of paired sister chromatids. In the budding yeast Saccharomyces cerevisiae, both of these divisions take place in a single nucleus, giving rise to the four-spored ascus. We have modeled the microtubules in 20 MI and 15 MII spindles by using reconstruction from electron micrographs of serially sectioned meiotic cells. Meiotic spindles contain more microtubules than their mitotic counterparts, with the highest number in MI spindles. It is possible to differentiate between MI versus MII spindles based on microtubule numbers and organization. Similar to mitotic spindles, kinetochores in either MI or MII are attached by a single microtubule. The models indicate that the kinetochores of paired homologous chromosomes in MI or sister chromatids in MII are separated at metaphase, similar to mitotic cells. Examination of both MI and MII spindles reveals that anaphase A likely occurs in addition to anaphase B and that these movements are concurrent. This analysis offers a structural basis for considering meiotic segregation in yeast and for the analysis of mutants defective in this process.
Mammalian PIG-X and Yeast Pbn1p Are the Essential Components of Glycosylphosphatidylinositol-Mannosyltransferase I
Authors: Ashida Hisashi , Hong Yeongjin , Murakami Yoshiko , Shishioh Nobue , Sugimoto Nakaba , Kim Youn Uck , Maeda Yusuke , Kinoshita Taroh
Published: January 2005

Within the endoplasmic reticulum (ER), mannoses and glucoses, donated from dolichol-phosphate-mannose and -glucose, are transferred to N-glycan and GPI-anchor precursors, and serine/threonine residues in many proteins. Glycosyltransferases that mediate these reactions are ER-resident multitransmembrane proteins with common characteristics, forming a superfamily of >10 enzymes. Here, we report an essential component of glycosylphosphatidylinositol-mannosyltransferase I (GPI-MT-I), which transfers the first of the four mannoses in the GPI-anchor precursors. We isolated a Chinese hamster ovary (CHO) cell mutant defective in GPI-MT-I but not its catalytic component PIG-M. The mutant gene, termed phosphatidylinositolglycan-class X (PIG-X), encoded a 252-amino acid ER-resident type I transmembrane protein with a large lumenal domain. PIG-X and PIG-M formed a complex, and PIG-M expression was <10% in the absence of PIG-X, indicating that PIG-X stabilizes PIG-M. We found that Saccharomyces cerevisiae Pbn1p/YCL052Cp, which was previously reported to be involved in autoprocessing of proproteinase B, is the functional homologue of PIG-X; Pbn1p is critical for Gpi14p/YJR013Wp function, the yeast homologue of PIG-M. This is the first report of an essential subcomponent of glycosyltransferases using dolichol-phosphate-monosaccharide.
Growth Factor Receptor Binding Protein 2-mediated Recruitment of the RING Domain of Cbl to the Epidermal Growth Factor Receptor Is Essential and Sufficient to Support Receptor Endocytosis
Authors: Huang Fangtian , Sorkin Alexander
Published: January 2005

Knockdown of growth factor receptor binding protein 2 (Grb2) by RNA interference strongly inhibits clathrin-mediated endocytosis of the epidermal growth factor receptor (EGFR). To gain insights into the function of Grb2 in EGFR endocytosis, we have generated cell lines in which endogenous Grb2 was replaced by yellow fluorescent protein (YFP)-tagged Grb2 expressed at the physiological level. In these cells, Grb2-YFP fully reversed the inhibitory effect of Grb2 knockdown on EGFR endocytosis and, moreover, trafficked together with EGFR during endocytosis. Overexpression of Grb2-binding protein c-Cbl did not restore endocytosis in Grb2-depleted cells. However, EGFR endocytosis was rescued in Grb2-depleted cells by chimeric proteins consisting of the Src homology (SH) 2 domain of Grb2 fused to c-Cbl. The “knockdown and rescue” analysis revealed that the expression of Cbl-Grb2/SH2 fusions containing RING finger domain of Cbl restores normal ubiquitylation and internalization of the EGFR in the absence of Grb2, consistent with the important role of the RING domain in EGFR endocytosis. In contrast, the carboxy-terminal domain of Cbl, when attached to Grb2 SH2 domain, had 4 times smaller endocytosis-rescue effect compared with the RING-containing chimeras. Together, the data suggest that the interaction of Cbl carboxy terminus with CIN85 has a minor and a redundant role in EGFR internalization. We concluded that Grb2-mediated recruitment of the functional RING domain of Cbl to the EGFR is essential and sufficient to support receptor endocytosis.
Guided tissue regeneration in human gingival recessions
Authors: Trombelli Leonardo , Minenna Luigi , Farina Roberto , Scabbia Alessandro
Published: January 2005

Objective: The aim of the present study was to evaluate the changes of the mucogingival complex of guided tissue regeneration (GTR)‐treated gingival recession defects over a 10‐year follow‐up.

Methods: The study population consisted of 20 patients, 11 males and nine females, mean age: 44.3±10.4 years, each contributing one recession defect treated with a polytetrafluoroethylene membrane. Eight patients were smokers at the time of surgery and at 10 years post‐surgery. Recession depth (RD), probing depth clinical attachment level (CAL), and width of keratinized gingiva (KG) were assessed immediately before surgery, at 6 months, 4 years and 10 years post‐surgery.

Results: RD was 0.9±0.6 mm at 6 months, 1.0±1.3 mm at 4 years and 1.3±1.6 mm at 10 years. CAL amounted to 1.9±1.0 mm at 6 months and shifted to 2.2±1.4 and 2.6±1.6 mm at 4 years and 10 years, respectively. KG significantly increased following surgery and remained stable thereafter. At 10‐year examination, no significant changes from 4‐year evaluation were observed. Differences in periodontal parameters between smokers and non‐smokers were not statistically significant.

Conclusion: In conclusion, the results of the present study failed to demonstrate changes over time in the clinical outcome achieved following GTR procedure in gingival recession defects over a period between 4 and 10 years post‐surgery.
Ghrelin: more than a natural GH secretagogue and/or an orexigenic factor
Authors: Ghigo E. , Broglio F. , Arvat E. , Maccario M. , Papotti M. , Muccioli G.
Published: January 2005

Ghrelin, an acylated peptide produced predominantly by the stomach, has been discovered to be a natural ligand of the growth hormone secretagogue receptor type 1a (GHS‐R1a). Ghrelin has recently attracted considerable interest as a new orexigenic factor. However, ghrelin exerts several other neuroendocrine, metabolic and also nonendocrine actions that are explained by the widespread distribution of ghrelin and GHS‐R expression. The likely existence of GHS‐R subtypes and evidence that the neuroendocrine actions, but not all the other actions, of ghrelin depend on its acylation in serine‐3 revealed a system whose complexity had not been completely explored by studying synthetic GHS. Ghrelin secretion is mainly regulated by metabolic signals and, in turn, the modulatory action of ghrelin on the control of food intake and energy metabolism seems to be among its most important biological actions. However, according to a recent study, ghrelin‐null mice are neither anorectics nor dwarfs and this evidence clearly depicts a remarkable difference from leptin null mice. Nevertheless, the original and fascinating story of ghrelin, as well as its potential pathophysiological implications in endocrinology and internal medicine, is not definitively cancelled by these data as GHS‐R1a null aged mice show significant alterations in body composition and growth, in glucose metabolism, cardiac function and contextual memory. Besides potential clinical implications for natural or synthetic ghrelin analogues acting as agonists or antagonists, there are several open questions awaiting an answer. How many ghrelin receptor subtypes exist? Is ghrelin ‘the’ or just ‘a’ GHS‐R ligand? That is, are there other natural GHS‐R ligands? Is there a functional balance between acylated and unacylated ghrelin forms, potentially with different actions? Within the next few years suitable answers to these questions will probably be found, making it possible to gain a better knowledge of ghrelin's potential clinical perspectives.
Reduced insulin sensitivity and the presence of cardiovascular risk factors in short prepubertal children born small for gestational age (SGA)
Authors: Arends N. J. T. , Boonstra V. H. , Duivenvoorden H. J. , Hofman P. L. , Cutfield W. S. , Hokken‐Koelega A. C. S.
Published: January 2005

Background  Epidemiological studies have shown that the metabolic syndrome, a combination of type 2 diabetes mellitus, hypertension, dyslipidaemia and a high body mass index (BMI), occurs more frequently among adults who were born with a low birth weight. Because insulin is thought to play a key role in the pathogenesis of this syndrome we investigated insulin sensitivity and risk factors for cardiovascular disease in short prepubertal children born small for gestational age (SGA).

Patients and Methods  Frequently sampled intravenous glucose tolerance tests (FSIGT) were performed in 28 short prepubertal children born SGA. Short stature was defined as a height < –2SD. SGA was defined as a birth length and/or a birth weight for gestational age < –2SD. Twelve short children born appropriate for gestational age (AGA) were used as controls for the FSIGT's results only. AGA was defined as a birth weight and/or birth length for gestational age > –2SD. In short SGA children, blood pressure (BP), fasting levels of serum free fatty acids (FFA), triglycerides (TG), total cholesterol (TC), high‐density lipoprotein (HDL) cholesterol and low‐density lipoprotein (LDL) were measured and compared to reference values.

Results  Mean insulin sensitivity (Si) level in short SGA children was significantly reduced to 38% of the mean Si level measured in short AGA controls (P = 0·004). Mean acute insulin response (AIR) was significantly higher in SGA children compared to short AGA controls (P < 0·001). Differences in Si and AIR between the two groups remained significant after adjusting for age and BMI (P < 0·001 and P = 0·003, respectively). The mean (SD) systolic BP SDS was 1·3 (1,1), being significantly higher than zero. Mean fasting serum levels of FFA, TC, TG, HDL and LDL were all within the normal range. However, 6 of the 28 SGA children had serum FFA levels above the normal range. Cardiovascular risk factors could statistically be represented in two clusters. Both clusters played a significant role in the development of insulin insensitivity (1/Si).

Conclusion  Although the metabolic syndrome has been described in adulthood, our study showed that risk factors for the development of type 2 diabetes mellitus and cardiovascular disease are already present during childhood in short prepubertal children born SGA, suggesting a pretype 2 diabetes mellitus phenotype.
Altered ghrelin and peptide YY responses to meals in bulimia nervosa
Authors: Kojima Shinya , Nakahara Toshihiro , Nagai Nobuatsu , Muranaga Tetsuro , Tanaka Muneki , Yasuhara Daisuke , Masuda Akinori , Date Yukari , Ueno Hiroaki , Nakazato Masamitsu , Naruo Tetsuro
Published: January 2005

Objective  In recent years great advances have been made in our understanding of the peripheral signals produced within the gastrointestinal tract that regulate appetite, such as ghrelin and peptide YY (PYY). While ghrelin elicites hunger signals, PYY elicites satiety. Therefore, alterations in hormone physiology may play a role in the pathogenesis of bulimia nervosa (BN). In this study, we investigated the postprandial profile of ghrelin and PYY levels in patients with BN.

Design and patients  Postprandial plasma ghrelin and PYY levels and insulin and glucose responses were measured in 10 patients with BN and 12 control patients in response to a standard 400 kcal meal.

Results  Basal ghrelin levels present in BN subjects (265·0 ± 25·5 pmol/l) were significantly higher than those in healthy controls (199·3 ± 18·4 pmol/l, P < 0·05), while basal PYY levels were equivalent in BN (14·6 ± 1·3 pmol/l) and control (12·8 ± 1·1 pmol/l, P = 0·30) subjects. Postprandial ghrelin suppression (decremental ghrelin area under the curve) was significantly attenuated in BN patients, compared to controls (−96·3 ± 26·8 pmol/l × 3 h vs. −178·2 ± 25·7 pmol/l × 3 h, P < 0·05). After a meal, the incremental PYY area under the curve in BN patients was significantly blunted from that observed in controls (9·2 ± 2·6 pmol/l × 3 h vs. 26·8 ± 3·2 pmol/l × 3 h, P < 0·01).Glucose and insulin responses to meals were similar between the two groups.

Conclusions  BN patients exhibit elevated ghrelin levels before meals with reduced ghrelin suppression after eating. In bulimia nervosa subjects, the rise in PYY levels after meals is also blunted. A gut–hypothalamic pathway involving peripheral signals, such as ghrelin and PYY, may be involved in the pathophysiology of BN.
The impact of acute elevation of non‐esterified fatty acids on insulin sensitivity and secretion in women with former gestational diabetes
Authors: McLachlan K. A. , Alford F. P.
Published: January 2005

Objectives  Elevations in non‐esterified fatty acids (NEFA) have been shown to decrease insulin action and secretion, and are a risk factor for the development of Type 2 diabetes. As women who have had gestational diabetes (GDM) are at increased risk of diabetes, we examined the effect of an acute elevation of NEFA on insulin secretion and action in these women.

Patients and design  Nineteen women with recent former GDM and 19 age‐ and BMI‐matched postpartum healthy control subjects underwent a 40‐min intravenous glucose tolerance test, with and without a preceding 2‐h infusion of 20% Intralipid. Insulin action was assessed by glucose disappearance (Kg) and insulin sensitivity (SI); insulin secretion by first phase insulin release (FPIR) and disposition index (DI).

Results  NEFA levels were similarly elevated in both groups by the Intralipid infusion (up to 1·140 ± 0·03 mm). As expected, the lipid infusion significantly reduced Kg (2·15 ± 0·13 vs. 1·69 ± 0·09/min, P < 0·001) and SI (3·14 ± 0·28 vs. 2·13 ± 0·17/min/mUl/min, P < 0·001) in all subjects, and these were significant within the GDM and control subgroups. FPIR was elevated in the Intralipid study in the total group of women (4·50 ± 0·50 vs. 5·02 ± 0·53, P = 0·02), but DI was significantly reduced (12·13 ± 1·1 vs. 8·83 ± 0·7, P < 0·001). There was no significant difference, however, in the absolute or percentage change in Kg, SI or FPIR with lipid infusion between the GDM and control groups. GDM status was not a predictor of the response of Kg, SI or FPIR to lipid infusion, rather, adiposity (% fat), average fasting NEFA levels and basal disposition index were associated.

Conclusion  These data suggest that women with former gestational diabetes, in contrast to other prediabetic states, are not more susceptible to the deleterious effects of an acute elevation in nonesterified fatty acids than matched control subjects.
Rosiglitazone improves insulin sensitivity and glucose tolerance in subjects with impaired glucose tolerance
Authors: Hung Yi‐Jen , Hsieh Chang‐Hsun , Pei Dee , Kuo Shi‐Wen , Lee Jiunn‐Tay , Wu Ling‐Yi , He Chih‐Tsueng , Lee Chien Hsing , Fan Sandra Chyi , Sheu Wayne Huey‐Herng
Published: January 2005

Objective  This study was designed to evaluate the effects of rosiglitazone (ROS) on insulin sensitivity, β‐cell function, and glycaemic response to glucose challenge and meal in subjects with impaired glucose tolerance (IGT).

Methods  Thirty patients with IGT (ages between 30 and 75 years and BMI (body mass index) ≤ 27 kg/m2) were randomly assigned to receive either placebo (n = 15) or ROS (4 mg/day) (n = 15). All participants underwent a 75‐g oral glucose tolerance test (OGTT), meal test, and frequently sampled intravenous glucose tolerance test (FSIGT) before and after the 12‐week treatment.

Results  After 12 weeks of ROS treatment, there were significant increases in total cholesterol (TC) (4·25 ± 0·22 vs 4·80 ± 0·17 mmol/l, P < 0·001), high‐density lipoprotein cholesterol (HDL‐C) (1·25 ± 0·07 vs 1·43 ± 0·06 mmol/l, P < 0·05), and low‐density lipoprotein cholesterol (LDL‐C) (2·70 ± 0·15 vs 3·37 ± 0·17 mmol/l, P < 0·05) without changes in triglyceride concentration, TC/HDL‐C and LDL‐C/HDL‐C ratio. Although the acute insulin response (AIR) to intravenous glucose and disposition index (measured as the ability of pancreatic β‐cell compensation in the presence of insulin resistance) remained unchanged, the insulin sensitivity (SI) and glucose effectiveness (SG) were remarkably elevated (0·38 ± 0·06 vs 0·54 ± 0·09 × 10−5 min−1/pmol, P < 0·05; 0·017 ± 0·002 vs 0·021 ± 0·001 min−1, P < 0·05, respectively) in the ROS group. The glucose, insulin, and c‐peptide areas under curve (AUC) in response to OGTT and the glucose and insulin AUC during meal were significantly ameliorated in the ROS group. Five out of 15 (33%) and two out of 15 (13%) subjects treated with ROS and placebo, respectively, reversed to normal response during OGTT (P < 0·05).

Conclusion  Rosiglitazone treatment significantly improved insulin resistance and reduced postchallenge glucose and insulin concentrations in patients with impaired glucose tolerance without remarkable effects on β‐cell secretory function.
Circulating osteoprotegerin and receptor activator of NF‐κB ligand system are associated with bone metabolism in middle‐aged males
Authors: Oh Ki Won , Rhee Eun Jung , Lee Won Young , Kim Sun Woo , Baek Ki Hyun , Kang Moo Il , Yun Eun Joo , Park Cheol Young , Ihm Sung Hee , Choi Moon Gi , Yoo Hyung Joon , Park Sung Woo
Published: January 2005

Objective  Osteoporosis is a growing health problem in males as well as in females. Sex hormones and insulin‐like growth factor‐I (IGF‐I) have been shown to be the major determinants in male bone metabolism. Osteoprotegerin (OPG) is a recently identified cytokine that acts as a decoy receptor for the receptor activator of NF‐κB ligand (RANKL). OPG and RANKL have been shown to be important regulators of osteoclastogenesis. However, the relationship between the OPG‐RANKL system and male bone status in human populations are unclear. Thus, the aim of this study was to investigate the relationship between the OPG‐RANKL system and bone mineral metabolism in males.

Patients and Measurements  Serum concentrations of OPG, RANKL, oestradiol, total testosterone and IGF‐I and bone mineral density (BMD) were measured in 80 Korean males aged 42–70 (mean age, 54·5 year). Enzyme‐linked immunosorbent assays were used to determine the serum concentrations of OPG and RANKL. Serum concentrations of oestradiol, total testosterone, IGF‐I and bone turnover markers were determined using standard methods. BMD at the lumbar spine and femoral neck were measured by dual energy X‐ray absorptiometry.

Results  We observed a significant negative correlation between the serum OPG levels and lumbar spine BMD (r =−0·259, P < 0·05) in Spearman correlation analysis. Serum OPG levels and RANKL/OPG ratios were found to be significantly correlated to the serum osteocalcin levels (r =− 0·254, P < 0·05; r = 0·264, P < 0·05) in Spearman correlation analysis. Serum OPG levels were found to be negatively correlated with serum oestradiol levels (r =−0·319, P < 0·01) in Spearman correlation analysis. In addition, a significant positive correlation was found between serum RANKL/OPG ratios and oestradiol levels (r = 0·374, P < 0·001) in Spearman correlation analysis. In contrast, Serum total testosterone and IGF‐I levels were not correlated with serum OPG levels or RANKL to OPG ratios in Spearman correlation analysis. In a multiple regression analysis, age, body mass index (BMI), and serum OPG levels were identified as a significant predictor for lumbar spine BMD, and age, BMI, serum OPG and RANKL levels for femoral neck BMD. In another multiple regression analysis, only serum oestradiol level was identified as a significant predictor for serum OPG or RANKL levels. In contrast, Serum total testosterone and IGF‐I levels were not correlated with serum OPG or RANKL levels in multiple regression analysis.

Conclusions  Our data show that the circulating OPG‐RANKL system is associated with bone metabolism in the male populations. Also, our data suggest that OPG and RANKL may be mediators of the effects of oestradiol in male bone metabolism.
Advanced heart failure: impact on older patients and informal carers
Authors: Aldred Hazel , Gott Merryn , Gariballa Salah
Published: January 2005

Aim.  This paper reports a study exploring the impact of advanced heart failure on the lives of older patients and their informal carers.

Background.  Prognosis is poor in heart failure, with more than a third of patients dying within 12 months of diagnosis, and end‐of‐life symptoms are distressing and poorly controlled. Although end‐of‐life care for people with heart failure has received increased attention in recent years, there are still few data on the impact of advanced heart failure on the lives of patients and their informal carers.

Methods.  Focused interviews were conducted with 10 older people with advanced heart failure and their nominated informal carer identified from one district general hospital in the United Kingdom (UK). Joint interviews were conducted with patients and carers in their own home. Thematic analysis was used to identify themes and subthemes.

Findings.  Heart failure affected all aspects of the lives of patients and carers and, in particular, curtailed everyday activities. Patients were very concerned about the ‘burden’ their illness placed on their carer, who in all cases was their partner, although carers did not conceptualize the situation in this way. The socially isolating influence of the condition on both patients and carers was compounded by lack of professional input, and confusion about diagnosis was evident. Concerns about the future were common and, although few participants reported having been explicitly told about their prognosis, many made realistic statements about their limited life expectancy.

Conclusions.  This older cohort of people suffering from heart failure appears to have needs not unlike those of patients with ‘terminal diseases’. When people are diagnosed with more familiar terminal illnesses, in particular cancer, they are given ongoing explanations, reassurance and support. Similar professional input is needed for patients with advanced heart failure and their carers.
Sense of coherence, coping and quality of life following a critical illness
Authors: Fok See Kee , Chair Sek Ying , Lopez Violeta
Published: January 2005

Aim.  This paper reports the findings of a study exploring the relationships among patients’ sense of coherence, coping ability and health‐related quality of life following a critical illness.

Background.  Sense of coherence is a strong determinant of positive health outcomes and successful coping. Promoting sense of coherence has been used for health promotion in the general public so that better coping ability will be achieved and, thus, better quality of life. There have been limited studies focusing on these aspects in critically ill patients, particularly during the weeks following discharge from intensive care units.

Methods.  Based on the salutogenic theoretical framework, a descriptive, correlational research design using telephone interviews was used. Participants’ outlook on life, quality of life and coping responses were measured using Chinese versions of Sense of Coherence scale, SF‐36 and Coping Scale, respectively.

Results.  Eighty‐eight people participated in the study. Sense of coherence was significantly correlated with quality of life (r = 0·28–0·69) and with coping ability (r = 0·58). Furthermore, coping ability was significantly correlated with six (r = 0·25–0·52) out of the eight dimensions of quality of life. It was also found that high household income and support from adult children were predictors of strong sense of coherence.

Conclusion.  Patients with a strong sense of coherence are likely to take an active role in shaping their own health outcomes. The results of this study will enable nurses to design interventions in the early phase of hospitalization to enhance patients’ sense of coherence and coping abilities following a critical illness so that quality of life can be promoted.
A theory of maternal engagement with public health nurses and family visitors
Authors: Jack Susan M. , DiCenso Alba , Lohfeld Lynne
Published: January 2005

Background.  Home visiting by public health nurses and family visitors is promoted as an important intervention for enhancing parent and child development. Mothers of children at‐risk for developmental delays tend to be the most difficult to access and engage, and commonly drop out of home visiting programmes prematurely.

Purpose.  This paper reports a study developing a theory that describes the process by which mothers of children at‐risk engage with public health nurses and family visitors in a blended home visiting programme.

Methods.  Grounded theory was used to guide the collection, recording, organization and analysis of the data. A purposeful sample of 20 mothers receiving public health nurse and family visitor home visits were recruited from a public health unit in Canada. Data were collected through client record reviews and 29 in‐depth interviews that explored participants’ experiences, beliefs and expectations about engagement. Data collection and analysis continued until all categories were saturated.

Findings.  Mothers felt vulnerable and frequently powerless when they allowed the service providers into their home. Mothers with children at‐risk engage with public health nurses and family visitors through a basic social process of limiting family vulnerability, which has three phases: (1) overcoming fear; (2) building trust; and (3) seeking mutuality. The personal characteristics, values, experiences and actions of the public health nurse, family visitor and mother influence the speed at which each phase is successfully negotiated and the ability to develop a connected relationship.

Conclusion.  Public health nurses working with families at risk need to identify client fears and perceptions related to home visiting, and to explain the role of public health nurses and family visitors to all family members. Given the importance that mothers place on the development of an interpersonal relationship, it is important for home visitors continually to assess the quality of their relationships with clients.
Role development and effective practice in specialist and advanced practice roles in acute hospital settings: systematic review and meta‐synthesis
Authors: Jones Myfanwy Lloyd
Published: January 2005

Aims.  This paper reports a study whose aim was to identify and synthesize qualitative research studies reporting barriers or facilitators to role development and/or effective practice in specialist and advanced nursing roles in acute hospital settings.

Background.  The number of clinical nurse specialist, nurse practitioner, advanced nurse practitioner and consultant nurse roles has grown substantially in recent years. Research has shown that nurses working in innovative roles encounter a range of barriers and facilitators to effective practice.

Methods.  Systematic literature searches were undertaken, and relevant studies identified using specific inclusion and exclusion criteria. The selected studies were appraised, and their findings synthesized using Ritchie and Spencer's ‘Framework’ approach.

Results.  Fourteen relevant studies were identified, mostly from the UK. They described a range of barriers and facilitators affecting specialist and advanced nursing practice. These related to the practitioner's personal characteristics and previous experience, professional and educational issues, managerial and organizational issues, relationships with other health care professionals, and resources. The factors most widely identified as important were relationships with other key personnel, and role definitions and expectations.

Conclusions.  Relationships with other staff groups and role ambiguity are the most important factors which hinder or facilitate the implementation of specialist and advanced nursing roles. These factors seem interlinked, and the associated problems do not appear to resolve spontaneously when staff become familiar with the new roles. In order to reduce role ambiguity and the consequent likelihood of negative responses we recommend that, when specialist and advanced nursing roles are introduced, clear role definitions and objectives are developed and communicated to relevant staff groups; these definitions and objectives should be updated as necessary.
Obesity in adults with Down syndrome: a case–control study
Authors: Melville C. A. , Cooper S.‐A. , McGrother C. W. , Thorp C. F. , Collacott R.
Published: January 2005

Background  Obesity has a negative impact upon mortality and morbidity. Studies report that obesity is more prevalent in individuals with Down syndrome than individuals with intellectual disabilities (ID) not associated with Down syndrome. However, there have been no studies using a methodology of matched comparison groups and findings from previous studies are contradictory.

Methods  A detailed method was used to identify all adults with ID in Leicestershire. Individuals were invited to participate in a medical examination – that included measurement of their height and weight, from which body mass index (BMI) was calculated. For each person with Down syndrome, an individual matched for gender, age and accommodation type was identified, from the Leicestershire ID database.

Results  The data for 247 matched pairs is reported. Women with Down syndrome had lower mean height and weight, but greater mean BMI than the matched pairs. Men with Down syndrome had a lower mean height and weight but there was no statistical difference in BMI compared to the matched pairs. Using World Health Organization categories of BMI, women with Down syndrome were more likely to be overweight or obese than their matched pairs (odds ratio = 2.17). Men with Down syndrome were more likely to be in the overweight category than their matched pairs but were less likely to be obese (odds ratio = 0.85).

Conclusions  This study demonstrates that, compared to a matched sample, there is a greater prevalence of obesity amongst women with Down syndrome but not men. As the impact on the health of people with Down syndrome of being overweight or obese is uncertain, this is an area that requires further study.
Underweight, obesity and exercise among adults with intellectual disabilities in supported accommodation in Northern England
Authors: Emerson E.
Published: January 2005

Background  Significant deviation from normal weight (obesity and underweight) and lack of physical exercise have been identified as three of the most significant global behavioural risks to health.

Methods  Body mass index (BMI) and levels of physical activity were measured in a sample of 1542 adults with intellectual disabilities (ID) receiving supported accommodation in nine geographical localities in Northern England. Comparative population data were extracted from the Health Survey for England 1998 and 2001.

Results  Men and women with ID living in supported accommodation are at increased risk of being significantly underweight and physically inactive. Women with ID living in supported accommodation are at increased risk of obesity. Within the population of people with ID living in supported accommodation increased behavioural health risks are associated with gender, severity of ID, age and location.

Conclusion  Significant deviation from normal weight and lack of physical exercise are significant behavioural risks to health among people with ID.
The evolutionary forces maintaining a wild polymorphism of Littorina saxatilis: model selection by computer simulations
Authors: Pérez‐Figueroa A. , Cruz F. , Carvajal‐Rodríguez A. , Rolán‐Alvarez E. , Caballero A.
Published: January 2005

Two rocky shore ecotypes of Littorina saxatilis from north‐west Spain live at different shore levels and habitats and have developed an incomplete reproductive isolation through size assortative mating. The system is regarded as an example of sympatric ecological speciation. Several experiments have indicated that different evolutionary forces (migration, assortative mating and habitat‐dependent selection) play a role in maintaining the polymorphism. However, an assessment of the combined contributions of these forces supporting the observed pattern in the wild is absent. A model selection procedure using computer simulations was used to investigate the contribution of the different evolutionary forces towards the maintenance of the polymorphism. The agreement between alternative models and experimental estimates for a number of parameters was quantified by a least square method. The results of the analysis show that the fittest evolutionary model for the observed polymorphism is characterized by a high gene flow, intermediate‐high reproductive isolation between ecotypes, and a moderate to strong selection against the nonresident ecotypes on each shore level. In addition, a substantial number of additive loci contributing to the selected trait and a narrow hybrid definition with respect to the phenotype are scenarios that better explain the polymorphism, whereas the ecotype fitnesses at the mid‐shore, the level of phenotypic plasticity, and environmental effects are not key parameters.
Nonantagonistic interactions between the sexes revealed by the ecological consequences of reproductive traits
Authors: Lacey Knowles L. , Brodie Hernandez B. , Markow T. A.
Published: January 2005

In addition to the obvious role reproductive traits play in mating‐system evolution, reproductive characters can also have critical ecological or life history consequences. In this study we examine the ecological consequences of mating for female cactophilic Drosophila to test different hypotheses about the processes driving divergence in reproductive characters. Comparisons between intra‐ and interpopulation matings suggest that population differences in mating benefits, namely increased desiccation resistance in mated females, is not solely attributable to either a male or female‐specific reproductive trait. Instead, the results indicate that increased desiccation resistance is a product of a male–female postmating–prezygotic interactions. The results underscore that postmating–prezygotic interactions can serve as an arena for the evolution of male characters that confer substantial benefits to females, not just costs arising from sexual conflict. Variation in the relative benefits conferred by mating between intra‐ and interpopulation matings also suggests that the relationship between speciation and divergence in reproductive characters via male–female interaction will be difficult to predict.