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Selected AbstractsStroke volume decreases during mild dynamic and static exercise in supine humansACTA PHYSIOLOGICA, Issue 2 2009M. Elstad Abstract Aim:, The contributions of cardiac output (CO) and total peripheral resistance to changes in arterial blood pressure are debated and differ between dynamic and static exercise. We studied the role stroke volume (SV) has in mild supine exercise. Methods:, We investigated 10 healthy, supine volunteers by continuous measurement of heart rate (HR), mean arterial blood pressure, SV (ultrasound Doppler) and femoral beat volume (ultrasound Doppler) during both dynamic mild leg exercise and static forearm exercise. This made it possible to study CO, femoral flow (FF) and both total and femoral peripheral resistance beat-by-beat. Results:, During a countdown period immediately prior to exercise, HR and mean arterial pressure increased, while SV decreased. During mild supine exercise, SV decreased by 5,8%, and most of this was explained by increased mean arterial pressure. Dynamic leg exercise doubled femoral beat volume, while static hand grip decreased femoral beat volume by 18%. FF is tightly regulated according to metabolic demand during both dynamic leg exercise and static forearm exercise. Conclusion:, Our three major findings are, firstly, that SV decreases during both dynamic and static mild supine exercise due to an increase in mean arterial pressure. Secondly, femoral beat volume decreases during static hand grip, but FF is unchanged due to the increase in HR. Finally, anticipatory responses to exercise are apparent prior to both dynamic and static exercise. SV changes contribute to CO changes and should be included in studies of central haemodynamics during exercise. [source] Changes in the contractile properties of motor units in the rat medial gastrocnemius muscle after one month of treadmill trainingACTA PHYSIOLOGICA, Issue 4 2008M. Pogrzebna Abstract Aim:, The influence of 4 weeks treadmill training on the contractile properties of motor units (MUs) in the rat medial gastrocnemius muscle was investigated. Methods:, A population of 18 Wistar rats was divided into two groups: trained on a treadmill (n = 7, locomotion speed 27 cm s,1, 1 km daily, 5 days a week, for 4 weeks) and control (n = 11). The contractile properties of isolated MUs were studied. Functional isolation of units was achieved by electrical stimulation of filaments of the ventral roots. A total of 299 MUs were investigated (142 in the control group and 157 in the trained group). They were divided into fast fatigable (FF), fast resistant to fatigue (FR) and slow (S). Their proportions and parameters of contractions were analysed. Results:, Following training, the number of FF units decreased and the number of FR units increased. The distribution of the fatigue index changed within these two types of fast units. The twitch and tetanus forces increased considerably in fast MUs, mainly in those of the FF type. The contraction and relaxation times shortened in the FR and S MUs. The steep part of the force,frequency curves shifted towards higher stimulation frequencies in FR and S units, while in FF units the shift was in the opposite direction. Conclusion:, The significant change in the proportions of fast MUs following training indicates FF to FR transformation. The various effects of training seen in the different MU types help explain the rationale behind mixed training. [source] Discordance between intramuscular triglyceride and insulin sensitivity in skeletal muscle of Zucker diabetic rats after treatment with fenofibrate and rosiglitazoneDIABETES OBESITY & METABOLISM, Issue 5 2007K. J. Nadeau Aim:, Intramyocellular triglyceride (IMTG) correlates with insulin resistance, but there is no clear causal relationship. Insulin resistance and associated hyperinsulinaemia may increase IMTG, via the insulin-regulated transcription factor, sterol regulatory element,binding protein 1 (SREBP-1). PPAR agonists may also affect IMTG via changes in insulin sensitivity, SREBP-1 or other factors. Methods:, We examined skeletal muscle IMTG and SREBP-1 expression, and metabolic parameters in Zucker diabetic fatty rats (ZDF) after 25 weeks of PPAR-, or PPAR-, administration. Results:, Compared with Zucker lean rats (ZL), untreated ZDF had significantly higher weights, serum glucose, insulin, free fatty acids, total cholesterol and triglycerides. IMTG and SREBP-1c messenger RNA (mRNA) were also higher in untreated ZDF; both were decreased by fenofibrate (FF). Rosiglitazone (Rosi), despite marked improvement in glycaemia, hyperinsulinaemia and hyperlipidaemia, failed to affect SREBP-1 expression, and increased body weight and IMTG. Rosi/FF combination caused less weight gain and no IMTG increase, despite metabolic effects similar to Rosi alone. Conclusions:, IMTG and SREBP-1c mRNA are high in the ZDF. FF and Rosi both improved insulin sensitivity but had opposite effects on IMTG. Thus, there was a clear discordance between insulin sensitivity and IMTG with PPAR agonists, indicating that IMTG and insulin sensitivity do not share a simple relationship. [source] Losartan modifies glomerular hyperfiltration and insulin sensitivity in type 1 diabetesDIABETES OBESITY & METABOLISM, Issue 6 2001S. Nielsen Aim: The effect of the angiotensin II receptor antagonist losartan on renal haemodynamics and insulin-mediated glucose disposal was examined in normotensive, normoalbuminuric type 1 diabetic patients using a double-blind, placebo-controlled, cross-over design. Methods: Diurnal blood pressure, glomerular filtration rate (GFR, determined using [125I]-iothalamate), renal plasma flow (RPF, determined using [131I]-hippuran) and urinary albumin excretion rate (UAE) were measured, and a hyperinsulinaemic, euglycaemic clamp with indirect calorimetry was performed in nine patients (age 30 ± 7 years (mean ±,s.d.), HbA1c 8.1 ± 1.1%) following 6 weeks' administration of either losartan 50 mg/day or placebo. Results: Diurnal blood pressure was significantly reduced after losartan compared with placebo (122/70 ± 11/8 vs. 130/76 ± 12/6 mmHg, p <,0.05). A significant decline in GFR (133 ± 23 vs. 140 ± 22 ml/min, p < 0.05) and filtration fraction (FF; GFR/RPF) (24.6 ± 3.5 vs. 26.2 ± 3.6%, p <,0.05) was observed in the losartan vs. placebo groups. RPF and UAE did not change. Isotopically determined glucose disposal rates were similar after losartan and placebo in the basal (2.61 ± 0.53 vs. 2.98 ± 0.93 mg/kg/min) and insulin-stimulated states (6.84 ± 2.52 vs. 6.97 ± 3.11 mg/kg/min). However, the glucose oxidation rate increased significantly after losartan vs. placebo in the basal state (1.72 ± 0.34 vs. 1.33 ± 0.18, mg/kg/min, p <,0.01) and during insulin stimulation (2.89 ± 0.75 vs. 2.40 ± 0.62 mg/kg/min, p <,0.03). Basal and insulin-stimulated non-oxidative glucose disposal tended to decrease after losartan; however, this was not significant. Endogenous glucose production and lipid oxidation were unchanged after treatment and similarly suppressed during hyperinsulinaemia. Glycaemic control, total cholesterol, high-density lipoprotein (HDL)-cholesterol and triglycerides were stable in both losartan and placebo groups. Conclusions: Losartan reduces blood pressure, glomerular hyperfiltration and FF, and improves basal and insulin-stimulated glucose oxidation in normotensive, normoalbuminuric type 1 diabetic patients. [source] Hippocampal long-term depression as an index of spatial working memoryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2002Kazuhito Nakao Abstract Long-term potentiation (LTP), a form of synaptic plasticity in the hippocampus, is a cellular model for the neural basis of learning and memory, but few studies have investigated the contribution of long-term depression (LTD), a counterpart of LTP. To address the possible relationship between hippocampal LTD and spatial performance, the spatial cognitive ability of a rat was assessed in a spontaneous alternation test and, thereafter, LTD in response to low-frequency burst stimulation (LFBS) was monitored in the dentate gyrus of the same rat under anaesthesia. To enhance a divergence in the ability for spatial performance, some of the animals received fimbria,fornix (FF) transection 14 days before the experiments. LTD was reliably induced by application of LFBS to the medial perforant path of intact rats, while no apparent LTD was elicited in rats with FF lesions. The behavioural parameters of spatial memory showed a significant correlation with the magnitude of LTD. We found no evidence that the cognitive ability correlated with other electrophysiological parameters, e.g. basal synaptic responses, stimulus intensity to produce half-maximal responses, paired-pulse facilitation or paired-pulse depression. These results suggest that the magnitude of LTD in the dentate gyrus serves as a reliable index of spatial cognitive ability, providing insights into the functional significance of hippocampal LTD. [source] Changes in contractile properties of motor units of the rat medial gastrocnemius muscle after spinal cord transectionEXPERIMENTAL PHYSIOLOGY, Issue 5 2006Jan Celichowski The effects of complete transection of the spinal cord at the level of Th9/10 on contractile properties of the motor units (MUs) in the rat medial gastrocnemius (MG) muscle were investigated. Our results indicate that 1 month after injury the contraction time (time-to-peak) and half-relaxation time were prolonged and the maximal tetanic force in most of the MUs in the MG muscle of spinal rats was reduced. The resistance to fatigue also decreased in most of the MUs in the MG of spinal animals. Moreover, the post-tetanic potentiation of twitches in MUs diminished after spinal cord transection. Criteria for the division of MUs into three types, namely slow (S), fast fatigue resistant (FR) and fast fatigable (FF), applied in intact animals, could not be directly used in spinal animals owing to changes in contractile properties of MUs. The ,sag' phenomenon observed in unfused tetani of fast units in intact animals essentially disappeared in spinal rats and it was only detected in few units, at low frequencies of stimulation only. Therefore, the MUs in spinal rats were classified as fast or slow on the basis of an adjusted borderline of 20 ms, instead of 18 ms as in intact animals, owing to a slightly longer contraction time of those fast motor units with the ,sag'. We conclude that all basic contractile properties of rat motor units in the medial gastrocnemius muscle are significantly changed 1 month after complete spinal cord transection, with the majority of motor units being more fatigable and slower than those of intact rats. [source] Identification of proNeuropeptide FFA peptides processed in neuronal and non-neuronal cells and in nervous tissueFEBS JOURNAL, Issue 20 2003Elisabeth Bonnard Peptides which should be generated from the neuropeptide FF (NPFF) precursor were identified in a neuronal (human neuroblastoma SH-SY5Y) cell line and in COS-7 cells after transient transfection of the human proNPFFA cDNA and were compared with those detected in the mouse spinal cord. After reverse-phase high performance liquid chromatography of soluble material, NPFF-related peptides were immunodetected with antisera raised against NPFF and identified by using on-line capillary liquid chromatography/nanospray ion trap tandem mass spectrometry. Neuronal and non-neuronal cells generated different peptides from the same precursor. In addition to NPFF, SQA-NPFF (Ser-Gln-Ala-Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-amide) and NPAF were identified in the human neuroblastoma while only NPFF was clearly identified in COS-7 cells. In mouse, in addition to previously detected NPFF and NPSF, SPA-NPFF (Ser-Pro-Ala-Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-amide), the homologous peptide of SQA-NPFF, were characterized. These data on intracellular processing of proNeuropeptide FFA are discussed in regard to the known enzymatic processing mechanisms. [source] Aligning Single-Walled Carbon Nanotubes By Means Of Langmuir,Blodgett Film Deposition: Optical, Morphological, and Photo-electrochemical StudiesADVANCED FUNCTIONAL MATERIALS, Issue 15 2010Gabriele Giancane Abstract An alkoxy-substituted poly(phenylene thiophene) is used in order to suspend single-walled carbon nanotubes in an organic solvent. The suspension is spread on the air,water interface of a Langmuir trough and the floating film is characterized by means of Brewster angle microscopy and UV-visible reflection spectroscopy and the compression isotherm is recorded. The polymer/carbon-nanotube blend is transferred onto different substrates using the Langmuir,Blodgett technique. AFM measurements indicate the formation of globular structures for the samples transferred at low surface-pressure values and a tubular morphology for high-pressure-deposited samples. AFM analysis is repeated on a sample exposed to soft X-rays for about 5,h and a highly organized structure of bundles of carbon nanotubes rises up. Samples with different numbers of layers are transferred onto ITO substrates by means of the Langmuir,Blodgett method and are tested as photocathodes in a photo-electrochemical cell. A Voc of 0.18,V, an Isc of 85.8,mA, FF of 40.0%, and , of (6.23,×,10,3)% are obtained. [source] Water-Soluble Polyfluorenes as an Interfacial Layer Leading to Cathode-Independent High Performance of Organic Solar CellsADVANCED FUNCTIONAL MATERIALS, Issue 12 2010Seung-Hwan Oh Abstract Novel poly[(9,9-bis((6,-(N,N,N -trimethylammonium)hexyl)-2,7-fluorene)- alt -(9,9-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)-9-fluorene)) dibromide (WPF-6-oxy-F) and poly[(9,9-bis((6,-(N,N,N -trimethylammonium)hexyl)-2,7-fluorene)- alt -(9,9-bis(2-(2-methoxyethoxy)ethyl)-fluorene)] dibromide (WPF-oxy-F) compounds are developed and the use of these water-soluble polymers as an interfacial layer for low-cost poly(3-hexylthiophene):phenyl-C61 butyric acid methyl ester (P3HT:PCBM) organic solar cells (OSCs) is investigated. When WPF-oxy-F or WPF-6-oxy-F is simply inserted between the active layer and the cathode as an interfacial dipole layer by spin-coating water-soluble polyfluorenes, the open-circuit voltage (Voc), fill factor (FF), and power-conversion efficiency (PCE) of photovoltaic cells with high work-function metal cathodes, such as Al, Ag, Au, and Cu, dramatically increases. For example, when WPF-6-oxy-F is used with Al, Ag, Au, or Cu, regardless of the work-function of the metal cathode, the Voc is 0.64, 0.64, 0.58, and 0.63,V, respectively, approaching the original value of the P3HT:PCBM system because of the formation of large interfacial dipoles through a reduction of the metal work-function. In particular, introducing WPF-6-oxy-F into a low-cost Cu cathode dramatically enhanced the device efficiency from 0.8% to 3.36%. [source] Identification of a novel REV1-interacting motif necessary for DNA polymerase , functionGENES TO CELLS, Issue 2 2009Eiji Ohashi When a replicative DNA polymerase (Pol) is stalled by damaged DNA, a "polymerase switch" recruits specialized translesion synthesis (TLS) DNA polymerase(s) to sites of damage. Mammalian cells have several TLS DNA polymerases, including the four Y-family enzymes (Pol,, Pol,, Pol, and REV1) that share multiple primary sequence motifs, but show preferential bypass of different DNA lesions. REV1 interacts with Pol,, Pol,, and Pol, and therefore appears to play a central role during TLS in vivo. Here we have investigated the molecular basis for interactions between REV1 and Pol,. We have identified novel REV1-interacting regions (RIRs) present in Pol,, Pol, and Pol,. Within the RIRs, the presence of two consecutive phenylalanines (FF) is essential for REV1-binding. The consensus sequence for REV1-binding is denoted by x-x-x-F-F-y-y-y-y (x, no specific residue and y, no specific residue but not proline). Our results identify structural requirements that are necessary for FF-flanking residues to confer interactions with REV1. A Pol, mutant lacking REV1-binding activity did not complement the genotoxin-sensitivity of Polk -null mouse embryonic fibroblast cells, thereby demonstrating that the REV1-interaction is essential for Pol, function in vivo. [source] For the Bright Future,Bulk Heterojunction Polymer Solar Cells with Power Conversion Efficiency of 7.4%ADVANCED MATERIALS, Issue 20 2010Yongye Liang The photovoltaic performance of polymer bulk heterojunction solar cells is studied systematically. Using a new benzodithiophene polymer (PTB7) and PC71BM (see figure) a power conversion efficiency of 7.4% has been achieved in PTB7/PC71BM-blend film, indicating a great potential and bright future for polymer solar cells (FF,=,fill factor, PCE,;=,power-conversion efficiency). [source] Are the Hirshfeld and Mulliken population analysis schemes consistent with chemical intuition?INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 9 2009Soumen Saha Abstract In the present article, we report a comparative study between the Hirshfeld and Mulliken population analysis schemes (abbreviated as HPA and MPA, respectively). Trends of atomic charges derived from these two population analysis schemes are compared with those expected from other commonly used chemical concepts like electronegativity, inductive effects, and resonance effects. Although previous studies on intramolecular reactivity sequences demonstrated that HPA generates reliable and non-negative (and thus physically more realistic) condensed Fukui function (FF) values, the present study reveals problems with the HPA charge partitioning technique. Specifically, HPA fails to reproduce reliable intermolecular and intramolecular charge trends in several systems. Reasons for the success and failure of HPA are discussed and a method for improving the Hirshfeld charge partitioning is proposed. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Comparative study of unscreened and screened molecular static linear polarizability in the Hartree,Fock, hybrid-density functional, and density functional modelsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 2 2008Rajendra R. Zope Abstract The sum-over-states (SOS) polarizabilities are calculated within approximate mean-field electron theories such as the Hartree,Fock approximation and density functional models using the eigenvalues and orbitals obtained from the self-consistent solution of the single-particle equations. The SOS polarizabilities are then compared with those calculated using the finite-field (FF) method. Three widely used mean-field models are as follows: (1) the Hartree,Fock (HF) method, (2) the three parameter hybrid generalized gradient approximation (GGA) (B3LYP), and (3) the parameter-free generalized gradient approximation due to Perdew,Burke,Ernzerhof (PBE). The comparison is carried out for polarizabilities of 142 molecules calculated using the 6-311++G(d,p) basis set at the geometries optimized at the B3LYP/6-311G** level. The results show that the SOS method almost always overestimates the FF polarizabilities in the PBE and B3LYP models. This trend is reversed in the HF method. A few exceptions to these trends are found. The mean absolute errors (MAE) in the screened (FF) and unscreened (SOS) polarizability are 0.78, 1.87, and 3.44 Å3 for the HF, B3LYP, and PBE-GGA methods, respectively. Finally, a simple scheme is devised to obtain FF quality polarizability from the SOS polarizability. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Discrimination between diastereoisomeric dipeptides by IR,UV double resonance spectroscopy and ab initio calculationsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 4 2005Ali G. Abo-Riziq Abstract We studied diastereoisomeric dipeptides, containing two chiral centers, by comparing ab initio calculations with laser desorption jet-cooling experiments. We studied the hetero-dipeptides LL,VF (L-Val-L-Phe) and DL,VF and the homo-dipeptides LL,FF (L-Phe-L-Phe) and LD,FF. Changing one of the chiral centers in each molecule leads to changes in the spectra that can be used to distinguish between diastereoisomeric pairs. We observed three different conformers for LL,VF, four for DL,VF, two for LL,FF, and one for LD,FF. By comparing the results from IR,UV double resonant spectroscopy with ab initio calculations, we can draw conclusions about the conformational structures. At the same time, the experimental data serve as a test for the computational results. We discuss the possibilities and limitations of the interplay between theory and experiment. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 [source] Dopamine increases renal oxygenation: a clinical study in post-cardiac surgery patientsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2010BENGT REDFORS Background: Imbalance of the renal medullary oxygen supply/demand relationship can cause ischaemic acute renal failure (ARF). The use of dopamine for prevention/treatment of ischaemic ARF has been questioned. It has been suggested that dopamine may increase renal oxygen consumption (RVO2) due to increased solute delivery to tubular cells, which may jeopardise renal oxygenation. Information on the effects of dopamine on renal perfusion, filtration and oxygenation in man is, however, lacking. We evaluated the effects of dopamine on renal blood flow (RBF), glomerular filtration rate (GFR), RVO2 and renal O2 demand/supply relationship, i.e. renal oxygen extraction (RO2Ex). Methods: Twelve uncomplicated, mechanically ventilated and sedated post-cardiac surgery patients with pre-operatively normal renal function were studied. Dopamine was sequentially infused at 2 and 4 ug/kg/min. Systemic haemodynamics were evaluated by a pulmonary artery catheter. Absolute RBF was measured using two independent techniques: by the renal vein thermodilution technique and by infusion clearance of paraaminohippuric acid (PAH), with a correction for renal extraction of PAH. The filtration fraction (FF) was measured by the renal extraction of 51Cr-EDTA. Results: Neither GFR, tubular sodium reabsorption nor RVO2 was affected by dopamine, which increased RBF (45,55%) with both methods, decreased renal vascular resistance (30,35%), FF (21,26%) and RO2Ex (28,34%). The RBF/CI ratio increased with dopamine. Dopamine decreased renal PAH extraction, suggestive of a flow distribution to the medulla. Conclusions: In post-cardiac surgery patients, dopamine increases the renal oxygenation by a pronounced renal pre-and post-glomerular vasodilation with no increases in GFR, tubular sodium reabsorption or renal oxygen consumption. [source] Are ectoparasite communities structured?JOURNAL OF ANIMAL ECOLOGY, Issue 6 2006Species co-occurrence, null models, temporal variation Summary 1We studied temporal variation in the structure of flea communities on small mammalian hosts from eastern Slovakia using null models. We asked (a) whether flea co-occurrences in infracommunities (in the individual hosts) in different hosts as well as in the component communities (in the host species) demonstrate a non-random pattern; (b) whether this pattern is indicative of either positive or negative flea species interactions; (c) whether this pattern varies temporally; and (d) whether the expression of this pattern is related to population size of either fleas or hosts or both. 2We constructed a presence/absence matrix of flea species for each temporal sample of a host species and calculated four metrics of co-occurrence, namely the C -score, the number of checkerboard species pairs, the number of species combinations and the variance ratio (V -ratio). Then we compared these metrics with the respective indices calculated for 5000 null matrices that were assembled randomly using two algorithms, namely fixed-fixed (FF) and fixed-equiprobable (FE). 3Most co-occurrence metrics calculated for real data did not differ significantly from the metrics calculated for simulated matrices using the FF algorithm. However, the indices observed for 42 of 75 presence/absence matrices differed significantly from the null expectations for the FE models. Non-randomness was detected mainly by the C -score and V -ratio metrics. In all cases, the direction of non-randomness was the same, namely the aggregation, not competition, of flea species in host individuals and host species. 4The inclusion or exclusion of the uninfested hosts in the FE models did not affect the results for individual host species. However, exclusion of the uninfested host species led to the acceptance of the null hypothesis for only six of 13 temporal samples of the component flea communities for which non-randomness was detected when the uninfested hosts were included in the analysis. 5In most host species, the absolute values of the standardized size effect of both the C -score and V -ratio increased with an increase in host density and a concomitant decrease in flea abundance and prevalence. 6Results of this study demonstrated that (a) flea assemblages on small mammalian hosts were structured at some times, whereas they appeared to be randomly assembled at other times; (b) whenever non-randomness of flea co-occurrences was detected, it suggested aggregation but never segregation of flea species in host individuals or populations; and (c) the expression of structure in flea assemblages depended on the level of density of both fleas and hosts. [source] Insulin-like growth factor I in growing thoroughbredsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 9-10 2007W. B. Staniar Summary The objective of this longitudinal study was to characterize growth and plasma insulin-like growth factor I (IGF-I) concentrations in pasture-raised thoroughbreds fed two sources of dietary energy. Mares and foals were randomly assigned to either a sugar and starch (SS) or fat and fibre (FF)-rich feed, and plasma IGF-I and growth were measured once a month from 1 to 16 months of age. These dependent variables were also compared with day length and ambient temperature. There was an association between plasma IGF-I concentration and average daily gain (ADG) (r = 0.32, p < 0.001). There were also clear seasonal patterns in both ADG and plasma IGF-I, with high values in June and May, and a low value in March. Plasma IGF-I and ADG were positively associated with day length and temperature. Plasma IGF-I was never higher (p > 0.10) in the FF group when compared with the SS group, and was higher in the SS group during a rapid growth phase in the spring of year 2 (p < 0.10). The results establish an association between ADG and IGF-I in the horse and indicate that environment and age may influence this relationship. In addition, plasma IGF-I is influenced by dietary energy source at particular times of year. This link has important implications in designing feeding management strategies that are aimed at addressing skeletal development. [source] Effects of glucose polymer with and without potassium and different diets on glycogen repletion after a treadmill exercise test in endurance horsesJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 11-12 2005T. M. Hess Glycogen repletion involves absorption of glucose and its uptake into the muscle cells through GLUT-4 transporters. In the muscle and adipose tissue GLUT,4 transporters facilitates the glucose transport in the presence of insulin and K+. Potassium supply has been shown to stimulate insulin secretion. This study tested the effects of a glucose polymer added with electrolytes containing potassium (GP+K) compared to a glucose polymer with electrolytes without potassium (GP-K) on glycogen repletion. Also it compared the effect of different diet adaptations on glycogen repletion. Six horses were fed a diet rich in sugar and starch (SS), and six horses a diet rich in fat and fibre (FF) for 6 months before the test. In a crossover designed study, 12 trained Arabian or Arabian cross horses were submitted to a glycogen depleting exercise test on the treadmill. After exercise stopped six horses were supplied with GP-K and six other horses supplied with GP+K, at a dose of 5 g/kg BW, and a rate of 1 g/kg BW/hour through naso-gastric gavage. Muscle biopsies were taken before, just after they stopped exercise, and 16 h after they had been supplied with glycogen replacing formulas, and analysed for muscle glycogen. Blood was taken before, after 3 h of exercise, after the stepwise exercise test, at 0, 1 and 4 h after exercise stopped and analysed for plasma glucose, insulin and [K+]. Muscle glycogen decreased from 516.41 ± 12.92 glucosyl units/kg dry weight muscle to 408.74 ± 12.92 glucosyl units/kg dry weight muscle (79%). Sixteen hours after the repletion protocol horses recovered their muscle glycogen to 458.53 ± 12.91 glucosyl units/kg dry weight muscle (89%). Plasma glucose had a glucose polymer by sampling effect (p = 0.013) and a feed by sampling effect (p = 0.022). Plasma glucose was higher in SS fed horses at 1 and 4 h after exercise. Plasma glucose was lower in GP+K supplied horses 4 h after exercise. Plasma insulin had a trend (p = 0.070) for a glucose polymer effect. No differences were found in muscle glycogen between the two GP treatments. Although the present results demonstrate that intensive nasogastric supplementation with glucose polymer can result in glycogen repletion approaching that following i.v. administration, the addition of potassium conferred no advantage. [source] Fire disturbance disrupts co-occurrence patterns of terrestrial vertebrates in Mediterranean woodlandsJOURNAL OF BIOGEOGRAPHY, Issue 5 2006Maurizio Sarà Abstract Aim, This paper uses null model analysis to explore the pattern of species co-occurrence of terrestrial vertebrate fauna in fire-prone, mixed evergreen oak woodlands. Location, The Erico,Quercion ilicis of the Mediterranean belt (50,800 m a.s.l.) in the Madonie mountain range, a regional park in northern Sicily (37°50, N, 14°05, E), Italy. Methods, The stratified sampling of vertebrates in a secondary succession of recent burned areas (BA, 1,2 years old), intermediate burned areas (INT, 4,10 years old) and ancient burned areas (CNB, > 50 years old), plus forest fragments left within burned areas (FF, 1,2 years old) permitted the comparison of patterns of species co-occurrence using a set of separate presence/absence matrices. First, the breeding avifauna derived from standardized point counts was analysed using Stone & Roberts'C -score, and by a null model algorithm (fixed/equiprobable). Secondly, the analysis was repeated using all vertebrate species recorded in the succession. Results, Sixty-five species were recorded in the 2-year study period in the four sample treatments. Birds were found to make up the largest component (63%) of the recorded assemblage. The BA treatment had the lowest species richness, followed in order by the small, medium and large FFs, and then by the CNBs. For both analyses (birds and total vertebrates), the C -scores were quite small and not significantly different from those that could be expected by chance in the BA and INT burned areas; this indicates a random co-occurrence among vertebrates of those assemblages. Contrariwise, for both analyses in the CNBs, the C -scores were large and significantly different from the simulated indices, thereby indicating a non-random co-occurrence pattern (segregation) of vertebrates in the undisturbed woodlands. In addition, C -score values for the surviving FFs show a significant aggregation of species. Main conclusions, The null model analyses highlighted a new aspect of fire disturbance in Mediterranean woodland ecosystems: the disruption in patterns of co-occurrence in the terrestrial vertebrate community. Wildfire alters community organization, inducing, for at least 10 years, a random aggregate of species. Communities re-assemble themselves, showing the occurrence of species segregation at least 50 years after fire. [source] Standardized analysis of UHMWPE wear particles from failed total joint arthroplastiesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 5 2002Jay D. Mabrey Abstract Periprosthetic tissue obtained at revision surgery from eight total hip replacement cases was hydrolyzed, and polyethylene debris particles were isolated from each case. Individual particles were analyzed by scanning electron microscopy (SEM) and computerized image analysis in accordance with ASTM F1877-98, a standard for quantitative description of wear debris. For comparison, periprosthetic tissues from eight total knee revision and four total shoulder revision cases were processed and analyzed with identical methods. A total of 2599 hip, 4345 knee, and 1200 shoulder particles were analyzed. The morphologies of the isolated polyethylene particles from the total hip specimens were distinctly different from the total knee and total shoulder particles. The mean equivalent circle diameter (ECD) for hip particles was 0.694 ,m ± 0.005; knee particles measured 1.190 ,m ±0.009; and shoulder particles 1.183 ,m ± 0.017. The ECD was significantly different between hip particles and those from the shoulder and knee. The mean aspect ratio (AR) for the hip particles was 1.626 ± 0.015, compared to the knee particles at 1.935 ± 0.015 and shoulder particles at 2.082 ± 0.033. The AR was statistically different among all three groups. Other descriptors from the ASTM standard, elongation (E), form factor (FF), and roundness (R) were all significantly different among the three groups of joints. This study demonstrates the utility of ASTM F1877-98 in differentiating wear debris particles from different sources. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 475,483, 2002 [source] Confocal imaging of chromatographic fouling under flow conditionsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2007Sun Chau Siu Abstract BACKGROUND: The fouling impact of selected fouling species was assessed by utilising confocal scanning laser microscopy (CSLM) to image a packed chromatographic bed during operation. A custom-made flow cell was packed with Q Sepharose FF and loaded with partially clarified E. coli homogenate. Selective, multicoloured fluorescent dyes were used to label a bovine serum albumin (BSA) test protein (Cy5.5), dsDNA (PicoGreen) and host cell proteins (HCPs) (Cy3). The fouling caused by the various fluorescently labelled components was visualised as a result of the fluorescence emitted by the PicoGreen-labelled dsDNA and the Cy3-labelled protein in the foulant stream, and by testing the adsorptive capacity of a test protein (BSA) onto the resin prior to and post-fouling as well as following the application of a common CIP procedure. RESULTS: Values for the effective diffusivity of BSA (De) were derived from the confocal images and the fouling impact was assessed by comparing De values obtained from different fouling scenarios. Under the most extreme conditions examined, fouling caused a 20% reduction in capacity compared to a fresh bed. BSA diffusivity did not appear to be affected by the fouling conditions studied. Sequential CIP using 15 CVs of 1 mol L,1 NaCl then 15 CVs of 1 mol L,1 NaOH was shown to be effective in removing nucleic acids and HCPs. Subsequent BSA adsorption showed that the CIP regime successfully restored the column capacity to its original value. In contrast, 15 CVs of 1 mol L,1 NaCl were ineffective in removing dsDNA but substantially removed HCPs. CONCLUSION: CSLM was demonstrated to be a useful tool for visualising fouling mechanisms. Comparing the results obtained by this technique using different modes of chromatographic operation provided insights into the fouling characteristics of finite baths versus packed beds. Copyright © 2007 Society of Chemical Industry [source] Theoretical studies on nonlinear optical properties of formaldehyde oligomers by ab initio and density functional theory methodsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 15 2005Hui-Yin Wu Abstract The first and second hyperpolarizability , and , are obtained for formaldehyde oligomers (H2CO)n (n = 1,7) using computational methods. We have used the finite field (FF) approach and hyperpolarizability density analysis (HDA) to predict the microscopic first and second nonlinear hyperpolarizability of the formaldehyde oligomers. The spatial contributions of electrons to the hyperpolarizability by using plots of HDA are presented. It has been found from the numerical stability checking of the hyperpolarizability calculations that the calculated values by FF method are more stable than those by HDA approach. The values of , are zero when n is even as the molecule possesses centrosymmetry, and when n is odd, the differences among , values are not clear. The , values are increased with increase in n. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1543,1564, 2005 [source] Screening for Alternative Antibiotics: An Investigation into the Antimicrobial Activities of Medicinal Food Plants of MauritiusJOURNAL OF FOOD SCIENCE, Issue 3 2010M.F. Mahomoodally ABSTRACT:, The present study was designed to evaluate the antimicrobial activities of 2 endemic medicinal plants; Faujasiopsis flexuosa,(Asteraceae) (FF) and Pittosporum senacia,(Pittosporaceae) (PS) and 2 exotic medicinal plants, Momordica charantia,(Cucurbitaceae) (MC) and Ocimum tenuiflorum,(Lamiaceae) (OT) that forms part of local pharmacopoeia of Mauritius and correlate any observed activity with its phytochemical profile. Aqueous and organic fractions of the leaves, fruits, and seeds of these plants were subjected to antimicrobial testing by the disc diffusion method against 8 clinical isolates of bacteria and 2 strains of fungus. It was found that MC, OT, and FF possessed antimicrobial properties against the test organisms. The MIC for MC ranged from 0.5 to 9 mg/mL and that of FF from 2 to 10 mg/mL and the lowest MIC value (0.5 mg/mL) was recorded for the unripe fruits of MC against E. coli. On the other hand, higher concentration of the unripe MC fruit extract of 9 mg/mL was needed to be effective against a resistant strain of Staphylococcus aureus,(MRSA). The antimicrobial effect against MRSA was lost upon ripening of the fruits. The methanolic extract of both MC and FF showed highest MIC values compared to the corresponding aqueous extract, which indicates the low efficacy and the need of higher doses of the plant extract. Phytochemical screening of the plants showed the presence of at least tannins, phenols, flavonoids, and alkaloids, which are known antimicrobial phyto-compounds. In conclusion, the observed antimicrobial properties would tend to further validate the medicinal properties of these commonly used endemic medicinal and food plants of Mauritius. [source] Fungistatic Activity of Heat-Treated Flaxseed Determined by Response Surface MethodologyJOURNAL OF FOOD SCIENCE, Issue 6 2008Y. Xu ABSTRACT:, The objective of this study was to evaluate the effect of heat treatment on the fungistatic activity of flaxseed (Linum usitatissimum) in potato dextrose agar (PDA) medium and a fresh noodle system. The radial growth of Penicillium chrysogenum, Aspergillus flavus, and a Penicillium sp. isolated from moldy noodles, as well as the mold count of fresh noodle enriched with heat treated flaxseed, were used to assess antifungal activity. A central composite design in the response surface methodology was used to predict the effect of heating temperature and time on antifungal activity of flaxseed flour (FF). Statistical analysis determined that the linear terms of both variables (that is, heating temperature and time) and the quadratic terms of the heating temperature had significant (P < 0.05) effects on the radial growth of all 3 test fungi and the mold count log-cycle reduction of fresh noodle. The interactions between the temperature and time were significant for all dependent variables (P < 0.05). Significant reductions in antifungal activities were found when FF was subjected to high temperatures, regardless of heating time. In contrast, prolonging the heating time did not substantially affect the antifungal activities of FF at low temperature. However, 60% of the antifungal activity was retained after FF was heated at 100 °C for 15 min, which suggests a potential use of FF as an antifungal additive in food products subjected to low to mild heat treatments. [source] A service evaluation to determine the effectiveness of current dietary advice in treating human immunodeficiency virus-associated weight loss and to highlight potential service improvementsJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 4 2008C.A. Hunt Background:, Weight loss and muscle wasting are experienced by many patients with human immunodeficiency virus (HIV) (Grinspoon et al., 2003). Malnutrition is an important predicator of morbidity and mortality; people who are malnourished who received antiretroviral treatment are six times more likely to die than those who are adequately nourished (Paton et al., 2006). The physical manifestations of muscle wasting can have significant psychosocial implications for HIV patients (Power et al., 2003; Sattler, 2003). The aim of this study to evaluate provision of dietetic care to patients referred for acute weight loss advice and identify areas for potential service improvement. Methods:, The data were gathered from the departmental dietetic activity statistics in 2007, diagnosis code ,HIV , acute weight loss'. Fifty-nine cards were located and baseline weight, height and body mass index (BMI) were recorded (two female, 57 male). Qualitative data on dietetic intervention were extracted from record cards , little and often eating approach, food fortification (FF), high energy high protein oral nutritional supplement (ONS) prescribed. Data were collected on body image, exercise and weight at follow-up visits during 2007. Results:, Forty-three percent of the patients referred for ,HIV-acute weight loss' were lost to follow-up. Forty-seven percent of the remaining patients had a BMI <20 kg m,2. Following their initial dietetic intervention, 81% of these patients had gained weight at the first follow-up. All had received nutritional counselling on little and often eating approach and FF; 75% had ONS prescribed. Average weight gain with nutritional counselling alone was 1.3 kg (2.1 kg) and for nutritional counselling plus supplementation was 2.1 kg (1.8 kg). This represented 2.5% (4.1%) and 3.9% (3.4%) weight gain, respectively. Discussion:, This evaluation has highlighted that patient follow-up frequency is an area for service improvement. Fifty-three per cent of patients (excluding those lost to follow up) had a BMI ,20 kg m,2 and were inaccurately recorded in the statistics as being referred for ,HIV-acute weight loss'. Fifty-two percent of these patients reported lipodystrophy and body image concerns, similar to findings of other studies. Fifty-six percent reported weight improvements following dietetic consultation. Body image is a frequent referral trigger, therefore improvements should be made to identify and treat patients with body shape issues. Conclusions:, Dietitians are effective at achieving weight gain in HIV positive patients with a BMI <20 kg m,2 using nutritional counselling methods with or without oral nutritional supplementation; these patients experienced a 3.3% weight gain. Strategies need to be implemented to reduce the number of patients lost to follow-up, as weight loss is a key morbidity and mortality indicator in HIV. References, Grinspoon, S. & Mulligan, K. (2003) Weight loss and wasting in patients infected with HIV. Clin. Infect. Dis.36 (Suppl. 2): 69,78. Nerad, J., Romeyn, M., Silverman, E., Allen-Reid, J., Dieterich, D., Merchant, J., Pelletier, V., Tinnerello, D. & Fenton, M. (2003) General nutritional management in patients infected with HIV. Clin. Infect. Dis.36 (Suppl. 2): 52,62. Ockenga, J., Grimble, R., Jonkers-Schuitema, C., Macallan, D., Melchior, J.C., Sauerwein, H.P., Schwenk, A. & Suttmann, U. (2006) ESPEN guidelines on enteral nutrition: wasting in HIV and other chronic infectious diseases. Clin. Nutr.25, 319,329. Paton, N.I., Sangeetha, S., Earnest, A. & Bellamy, R. (2006) The impact of malnutrition on survival and the CD4 count response in HIV-infected patients starting antiretroviral therapy. HIV Med.7, 232,330. Power, R., Tate, H.L., McGill, S.M. & Taylor, C. (2003) A qualitative study of the psychosocial implications of lipodystrophy syndrome on HIV positive individuals. Sex. Transm. Infect.79, 137,141. Sattler, F. (2003) Body habitus changes related to lipodystrophy. Clin. Infect. Dis36 (Suppl. 2): 84,90. [source] Determination of cardiac involvement in sarcoidosis by magnetic resonance imaging and Doppler echocardiographyJOURNAL OF INTERNAL MEDICINE, Issue 5 2002C. M. Sköld Abstract. Sköld CM, Larsen FF, Rasmussen E, Pehrsson SK, Eklund AG (Karolinska Hospital and Institutet, Stockholm, Sweden). Determination of cardiac involvement in sarcoidosis by magnetic resonance imaging and Doppler echocardiography. J Intern Med 2002; 252: 465,471. Objectives. To elucidate whether cardiac magnetic resonance imaging (MRI) could be useful in disclosing structural changes in the myocardium in sarcoidosis patients and to relate echo-Doppler derived indices of left ventricular function to electrocardiogram (ECG) findings. Design. The MRI was performed in 18 consecutive patients with sarcoidosis. Left ventricular ejection fraction (LVEF), i.e. systolic function, was estimated echocardiographically by Simpson's two-dimensional method (n = 16). Diastolic function was estimated by age-corrected Doppler-derived indices: isovolumetric relaxation time (IVRT), deceleration time (DT) and early filling/atrial contraction ratio (E/A ratio). Results. Eleven patients had conduction defects or dysrhythmias (ECG+) whilst seven patients had a normal ECG (ECG,). In two patients, high signalling, contrast-enhanced, isolated regions, suggestive of deposits, were seen in the left ventricular myocardium on MRI. Both these patients had abnormal ECGs and signs of systolic and/or diastolic dysfunction on echocardiography. LVEF was subnormal in seven of 10 of the ECG+ patients and in two of six of the ECG,. Signs of diastolic dysfunction were found in 59% and 56% of the measurements in the ECG+ and ECG, patients, respectively. Conclusion. We conclude (i) that myocardial deposits on MRI in sarcoidosis patients have a high specificity for cardiac involvement but a rather low sensitivity; (ii) that a substantial proportion of sarcoidosis patients with abnormal ECGs have echocardiographic signs of systolic and/or diastolic dysfunction. [source] Regulation of endogenous human NPFF2 receptor by neuropeptide FF in SK-N-MC neuroblastoma cell lineJOURNAL OF NEUROCHEMISTRY, Issue 2 2006Minna-Liisa Änkö Abstract Neuropeptide FF has many functions both in the CNS and periphery. Two G protein-coupled receptors (NPFF1 and NPFF2 receptors) have been identified for neuropeptide FF. The expression analysis of the peptide and receptors, together with pharmacological and physiological data, imply that NPFF2 receptor would be the primary receptor for neuropeptide FF. Here, we report for the first time a cell line endogenously expressing hNPFF2 receptor. These SK-N-MC neuroblastoma cells also express neuropeptide FF. We used the cells to investigate the hNPFF2 receptor function. The pertussis toxin-sensitive inhibition of adenylate cyclase activity upon receptor activation indicated coupling to Gi/o proteins. Upon agonist exposure, the receptors were internalized and the mitogen-activated protein kinase cascade was activated. Upon neuropeptide FF treatment, the actin cytoskeleton was reorganized in the cells. The expression of hNPFF2 receptor mRNA was up-regulated by neuropeptide FF. Concomitant with the receptor mRNA, the receptor protein expression was increased. The homologous regulation of hNPFF2 receptor correlates with our previous results in vivo showing that during inflammation, the up-regulation of neuropeptide FF mRNA precedes that of NPFF2 receptor. The regulation of hNPFF2 receptor by NPFF could also be important in the periphery where neuropeptide FF has been suggested to function as a hormone. [source] Stress analysis of the anterior tibial post in posterior stabilized knee prosthesesJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2007Chang-Hung Huang Abstract Recent retrieval studies have indicated a high incidence of polyethylene wear on the anterior tibial post caused by impingement. This study investigated the influences of post-cam design features and component alignment on the stress distribution in the anterior tibial post when subjected to the impingement loading. Two three-dimensional finite element models of posterior stabilized knee prostheses were constructed, one with flat on flat (FF) and another with curve on curve (CC) contact surfaces between anterior tibial post and femoral cam. The polyethylene insert was modeled with elastoplastic properties. Nine cases, three hyperextension angles (0°, 5°, and 10°) combined with three axial tibial rotations (0°, 2.5°, and 5°) simulating different component alignments were analyzed. A vertical compressive load of 2,000 N and an extension moment of 45 Nm were applied simultaneously. The FF model had larger stress increases than the CC model in both hyperextension and tibial rotation compared with the neutral position. The maximum increase for the FF model was 68% in peak contact stress, 125% in von Mises stress, and 58% in tensile stress in the extreme case of 10° of hyperextension combined with 5° of axial rotation. Stress concentration was found at the anterior corner of the post in the FF model; this was not found in the CC model. The curve on curve design can reduce edge loading on the tibial post, especially during axial tibiofemoral rotation. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:442,449, 2007 [source] Protein ion-exchange adsorption kineticsAICHE JOURNAL, Issue 7 2001J. A. Wesselingh The kinetics of the adsorption of the protein BSA on the ion exchanger Q-Sepharose FF were measured for several values of the pH and ionic strength, using several techniques. The measurements were best described with a model incorporating both surface and pore diffusion and with the chemical potential gradient as the driving force for diffusion. The surface-diffusion coefficients from this model show an inverse exponential dependency on the binding strength. This dependency can be explained by an activated jump mechanism. The pore-diffusion coefficient is much lower than that in free solution, which is probably caused by a combination of steric and electric exclusion. [source] Representational Models Associated With Fear of Failure in Adolescents and Young AdultsJOURNAL OF PERSONALITY, Issue 5 2003David E. Conroy As a descriptive trait, fear of failure (FF) has been associated with serious problems in achievement and health. Psychodynamic theories emphasizing interpersonal processes and early object relations are often used to explain the etiology of FF despite little comprehensive research on such theories in the FF domain. The present study employed the Structural Analysis of Social Behavior to study associations between FF and representational models of self and others among 211 high school and college-aged students and athletes. FF was strongly associated with hostile representational models of self while failing (large effect size). This hostility paralleled the manner in which high FF participants reported being treated by their parents and most significant instructors (all moderate effect sizes). Overall, results supported the complementary nature of these theoretical perspectives and provided further evidence for interpersonal theories of FF. [source] | ||||||||||||||||||||||||||||