bluuebunny/crossref_metadata_2025 huggingface dataset:
Self- and cross-incompatibility in Asparagus officinalis and Asparagus densiflorus cv. Sprengeri
Authors: Marcellán O. N. , Camadro E. L.
Published: January 2008

Garden asparagus, Asparagus officinalis L. (off), is dioecious and reproductively isolated from a related ornamental, monoecious Asparagus densifiorus (Kunth) Jessop cv. Sprengeri (spr). Since the latter is a potentially valuable source of germplasm, a study was initiated to identify hybridization barriers. Intra- and inter-specific crosses were made using 32 plants of two commercial cultivars of off and 17 plants of three introductions of spr. Part of the pollinated pistils were fixed and examined via fluorescence microscopy. In some combinations of genotypes, incompatibility reactions were detected: (i) off × off: in the stigmatic tissue, (ii) spr × spr: on the stigmatic surface and in the style, and (iii) spr × off: on the stigmatic surface, in the stigmatic tissue, and in the style. Although pollen tubes reached the ovules in most combinations of genotypes, seeds were only produced in intraspecific crosses. It is concluded that two types of internal barriers are acting: cross-incompatibility at the pollen–stigma and pollen–style levels, and stronger post-stylar barriers that had not been determined yet. Keywords: Asparagus densifiorus cv. Sprengeri, Asparagus officinalis, cross-incompatibility, reproductive isolation.
Comparative longevity of seeds of five tropical rain forest woody species stored under different moisture conditions
Authors: Vázquez-Yanes Carlos , Orozco-Segovia Alma
Published: January 2008

Seeds of five plant species from the tropical rain forest of southeastern Mexico were stored for up to 7 years under two divergent moisture regimes at room temperature: (i) air-dried seeds were stored in paper bags and (ii) water-imbibed seeds were stored in Petri dishes kept in total darkness. Seeds in the latter regime remained dormant because of an absolute requirement of light for germination. Another experiment involved the storage of seeds of one of the species in a gradient of intermediate moisture conditions within glass chambers. Results indicate that water-imbibed seeds retain viability for a longer time than any of the other moisture levels employed. This agreed with observations made on photoblastic lettuce seeds by other authors. Keywords: Carica, Piper, longevity of imbibed seeds, soil seed bank, tropical rain forest, Urera.
Études mycologique, entomologique et physico-chimique de troncs de Betula pendula en voie de dégradation. I. Répartition spatiale de l'état physico-chimique et de la mycoflore des troncs
Authors: Sigrist Marie-Hélène Prince , Job Daniel
Published: January 2008

Decaying Betula pendula Roth trunks (measuring about 6 m in length) with brown rot or white rot were analyzed for the followings: stage of decay, wood structure, porosity, chemical composition of decayed wood, spatial distribution of fungal biomass, and mycoflora diversity. The fungal biomass in the trunks, although heterogeneous, is higher in white rot than in brown rot. As expected, the lignin/holocellulose ratio is higher in brown rot than in white rot (maximum 14.83 versus 0.67). Brown rot is generally more porous than white rot and presents a higher water absorption capacity but it retains less air. The results show that the basidiomycetes mycoflora is active in the white rot decay process. However it is not involved in the brown rot decay process because the wood is already much decayed (as much as 80% and more of lignin content). With the exception of moulds, the only mycoflora that could be isolated repetitively from the brown rot station was in fact pockets of white rot. Moreover, in brown rot, none of the epiflora matched the isolated endoflora. Keywords: white rot, brown rot, mycoflora, biomass.
Prediction of Maximal Oxygen Uptake From a Modified Canadian Aerobic Fitness Test
Authors: Weller Iris M. R. , Thomas Scott G. , Corey Paul N. , Cox Michael H.
Published: January 2008

The purpose of the present study was to increase the accuracy of prediction of [Formula: see text] from the Canadian Aerobic Fitness Test (CAFT) by modifying the protocol and developing a new equation. Males and females between the ages of 15 and 69 years (n = 129) were tested on four occasions. Each subject performed four submaximal step tests (modified CAFT protocol) and a maximal treadmill test. The modification of the protocol consisted of allowing each subject to complete the number of stages needed to reach a target heart rate of 85% of age-predicted maximum. This required adding a new Stage 8 for men and Stages 7 and 8 for women. The prediction equation resulting from regression analysis was, [Formula: see text] (ml∙kg−1∙min−1) = 32.0 + 16.0 [Formula: see text] Age − 0.17 Wt (R2 − 0.77; δ2 − 26.6), where [Formula: see text] = oxygen cost of stepping at the final level (L∙min−1), Age = age (yrs), and Wt = body mass (kg). Key words: exercise test, oxygen consumption, predictive value of tests, physical fitness, epidemiologic methods
Metabolic Cost of Ice and In-Line Skating in Division I Collegiate Ice Hockey Players
Authors: Carroll Todd R. , Bacharach David , Kelly John , Rudrud Erik , Karns Patrick
Published: January 2008

This study compared the metabolic cost of ice skating and in-line skating in Division I collegiate hockey players. Heart rate and oxygen uptake were compared between the two conditions at three skating velocities: 12.5 km∙h−1, 16.5 km∙h−1 and 20 km∙h−1. Twelve subjects were tested on two occasions: on ice (ice skating) and off ice (in-line skating). They skated for 3 min at each velocity, with heart rate recording and gas collection taking place during the final 30 s of each stage. A two-factor repeated measures ANOVA revealed that the chosen velocities affected the two conditions differently for heart rate (p <.01). No interaction between condition and velocity was found for absolute (p <.43) and relative (p <.15) oxygen uptake. In-line skating produced significantly greater heart rate values and absolute oxygen uptake values than ice skating at all three velocities (p <.05). In-line skating also generated significantly greater relative oxygen uptake values at 16.5 km∙h−1 and 20 km∙h−1. Results suggest that the metabolic cost of in-line skating is greater than that of ice skating for collegiate ice hockey players when skating at three velocities similar to those skated during game conditions. Key words: exercise, heart rate, oxygen uptake, velocity
Cardiovascular Adaptations in 8- to 12-Year-Old Boys Following a 14-Week Running Program
Authors: Mahon Anthony D. , Vaccaro Paul
Published: January 2008

This study examined the effects of a 14-week running program on [Formula: see text], as well as cardiac output [Formula: see text] and arterial-venous O2 difference (a-vO2 dif) at submaximal intensities corresponding to 50 and 75% of [Formula: see text]. Thirteen boys (mean age 10.6 ± 1.2 yrs) served as experimental subjects while 13 other boys of similar age (mean age 10.2 ± 1.2 yrs) served as controls. Mean [Formula: see text] in the runners increased 13%, from 44.2 ± 7.0 to 49.9 ± 6.3 ml∙kg−1∙min−1. Posttraining [Formula: see text] during submaximal and maximal exercise was significantly (p < 0.05) greater in the runners than in the controls. [Formula: see text] and SV exhibited an increase of 10% at each intensity, but posttraining differences between groups were not significant (p > 0.05). A-vO2 dif increased by 8% at 50% of [Formula: see text] and by 6% at 75% of [Formula: see text], and was significantly greater in the runners following training. These results indicate that increases in submaximal relative [Formula: see text] in children are mediated by increases in a-vO2 dif and [Formula: see text]. Key words: cardiac output, arterial-venous oxygen difference, [Formula: see text], CO2 rebreathing, distance running
Population Evaluations of Health Related Fitness From Perceptions of Physical Activity and Fitness
Authors: Shephard Roy J. , Bouchard Claude
Published: January 2008

The possibility of predicting health related fitness using questions on occupational and leisure activity was explored in 172 men and 178 women. ANOVA and multiple regression equations related questionnaire responses to objective fitness measures including body mass index, circumferences, skinfolds, body fat, blood glucose, uric acid, total cholesterol, HDL-cholesterol and triglycerides, PWC150, blood pressures, and resting heart rate. Reported occupational activities bore little relationship to health related fitness. Self-perceptions of moderately frequent and moderately intense leisure activity, plus at least average perceived fitness relative to age-matched peers, were associated with a favourable body fat content and lipid profile, whereas indicators of cardiovascular health (a low resting heart rate and a high PWC150) were linked with perceptions of frequent and intense activity, plus a perceived fitness level higher than that of a peer reference group. Based on these findings, a simple scoring of reported activity for use in fitness counseling is suggested. Key words: cardiovascular fitness, leisure activity, metabolic fitness, occupational activity, perceived activity
The Laboratory Assessment of Endurance Performance in Cyclists
Authors: Hopkins Susan R. , McKenzie Donald C.
Published: January 2008

Performance in endurance activities depends on maximal aerobic capacity [Formula: see text] and the ability to sustain a high percentage of [Formula: see text] over time. This study examined whether noninvasive laboratory measures would be valid predictors of endurance performance in an individual-start bicycle race (TT). Eight experienced male cyclists (age = 25.1 ± 3.3 years, weight = 75.0 ± 5.7 kg, [Formula: see text]) performed a progressive incremental exercise test to exhaustion on a cycle ergometer. [Formula: see text], maximum power output, and ventilatory threshold were determined. Later the subjects completed a 40-km TT. Power output at the ventilatory threshold (VT watts) was correlated with race performance time and calculated power output during the competition (r = −0.81; r = 0.82). VT watts and [Formula: see text] accounted for 75% of the variance between subjects (r = 0.91) in performance time. These data indicate that simple laboratory measures can predict TT performance in trained cyclists. Individual differences may be accounted for by motivation, aerodynamic position, and efficiency. Key words: exercise, laboratory methods, [Formula: see text], athletes
Neural Drives to Breathing During Exercise
Authors: Duffin James
Published: January 2008

This article presents the author's views about the neural drives to breathing during exercise. Two hypotheses are developed, the first being that the rapid changes in ventilation at the start and end of exercise are due to a fast neural drive whose magnitude is related to the frequency of limb movement. Experimental data are presented that this drive persists throughout exercise but declines as exercise continues. Second, the excessive increase in ventilation that occurs above the first ventilatory threshold during an incremental exercise test is due to a heavy exercise neural drive whose magnitude is related to the motor commands to the exercising muscles. Using the electromyographical activity of the working muscles as an index of the strength of the motor commands, experimental evidence is presented showing the coincidence of the first ventilatory threshold and that for the electromyographic activity of the working muscles during incremental exercise tests. Key words: neural drive hypotheses, treadmill speed vs grade, start and end of exercise, incremental exercise tests, hyperoxia
Respiratory Control During Exercise: Hormones, Osmolality, Strong Ions, and Paco2
Authors: Jennings Donald B.
Published: January 2008

For optimal performance of exercising muscle, the charge state of proteins must be maintained; the pH environment of protein histidine imidazole groups must be coordinated with their pK. During exercise, increasing temperature and osmolality as well as changes in strong ions affect the pK of imidazole groups. Production of strong organic anions also decreases the concentration difference between strong cations and anions (strong ion difference, or [SID]), causing a metabolic acidosis in peripheral tissues. Central chemoreceptors regulate [Formula: see text] in relation to the [SID] of brain fluids to maintain a "constant" brain [H+]. In addition, increased osmolality, angiotensin II, and vasopressin during exercise may stimulate circumventricular organs of the brain and interact with chemical control of ventilation. Changes in [SID] of brain fluids during exercise are negligible compared to systemic decreases in [SID]; thus, regulation of [Formula: see text] to maintain brain [H+] homeostasis cannot simultaneously compensate for greater changes in [SID] in peripheral tissues. Key words: circumventricular organs, central chemoreception, angiotensin II, vasopressin, alphastat theory
Do Carotid Chemoreceptors Inhibit the Hyperventilatory Response to Heavy Exercise?
Authors: Dempsey Jerome A. , Smith Curtis A.
Published: January 2008

In this paper two types of evidence are presented which question the commonly presumed role of carotid chemoreceptor stimulation as the primary mediator of the hyperventilatory response to heavy exercise. First, carotid-body denervation in ponies increases their hyperventilatory response to heavy exercise. Second, the awake dog and the goat at rest show an immediate and substantial depression of tidal volume and of ventilation when their isolated carotid chemoreceptors are made hypocapnic. Accordingly, it is proposed that during heavy exercise the carotid chemoreceptors are inhibitory to respiratory motor output and that the cause of the hyperventilatory response originates from extrachemoreceptor, locomotor-linked, feed-forward stimuli. Key words: hypocapnic inhibition, medullary chemoreceptors, locomotor-linked stimuli, feed-forward
Blood Pressure Responses to a Progressive Step Test in Normotensive Males and Females
Authors: Jetté Maurice , Quenneville Josée , Sidney Ken , Landry Fernand
Published: January 2008

This study documents the blood pressure responses to a progressive step test adapted from the Canadian Aerobic Fitness Test (CAFT). Subjects were administered the first five stages of the CAFT in a progressive and discontinuous manner. Mean heart rate, SBP, and ΔSBP increased linearly with exercise intensity, while mean diastolic blood pressure remained stable. The variables that contributed most to ASBP (Stage 3) in males were age and degree of participation in physical activity, and in females the variables were body weight and degree of participation. Criteria for the detection of an exaggerated (mean ΔSBP + 1 SD) and highly exaggerated (mean ΔSBP + 2 SD) SBP response were defined. Resting normotensive individuals who demonstrate an excessive exercise blood pressure response seem to do so at the lowest levels of stepping intensities. This step test protocol appears to be a useful and practical procedure for assessing the exercise blood pressure response in higher risk individuals. Key words: exercise testing, fitness appraisal, exercise hypertension, risk appraisal
Validation of the Sensormedics (S2900Z) Metabolic Cart for Pediatric Exercise Testing
Authors: Unnithan Viswanath B. , Wilson John , Buchanan Duncan , Timmons Jamie A. , Paton James Y.
Published: January 2008

The accuracy of many microprocessor controlled exercise testing systems has not been established, particularly for testing children. A metabolic cart (Sensormedics S2900Z) was validated against a reference system (Douglas bag) in children. The systems were tested using 10 active, healthy children (age 11.6 ± 2.3 yrs) during physiological steady state at two exercise intensities, submaximal walking and running. Eight children performed a high ventilatory flow (HVF) protocol, running for 11 min. All 10 performed a low ventilatory flow (LVF) protocol, walking for 11 min. In both, gas samples were measured after 6 to 7 and 10 to 11 min into the Douglas bag, and after 8 to 9 min by the test system. There was minimal evidence of bias for [Formula: see text] at either ventilation rate. Greater variability was noted for FeCO2 and [Formula: see text]. In conclusion, the Sensormedics S2900Z appears to be adequate for testing children. Key words: microprocessor, bias, ventilatory flows
Can Estrogens Diminish Exercise Induced Muscle Damage?
Authors: Tiidus Peter M.
Published: January 2008

Estrogens are female sex hormones that may also protect against peroxidative damage of membrane lipids and low density lipoproteins (LDL). Studies have reported that female rats have greater protection against free radical induced lipid peroxidation and muscle damage consequent to exercise than do male rats. It has been suggested that the lower susceptibility to exercise induced oxidative stress and muscle membrane disruption of female rats may be due primarily to the antioxidant and membrane stabilizing properties of estrogens. Studies on humans have indicated that the lower incidence of atherosclerosis seen in premenopausal females in comparison to males is due at least in part to the ability of estrogens to diminish LDL peroxidation. However, there is little evidence as to the potential of estrogens to protect human females from free radical induced peroxidation and muscle damage due to exercise. This paper reviews the evidence for membrane stabilization potential of estrogens and their possible mechanisms, and speculates as to the potential significance of this for human exercise. Key words: estradiol, atherosclerosis, free radicals, peroxidation, antioxidants
Central Adaptations in Aerobic Circuit Versus Walking/Jogging Trained Cardiac Patients
Authors: Goodman Leonard S. , McKenzie Donald C. , Nath Colin R. , Schamberger Wolfgang , Taunton Jack E. , Ammann Walter C.
Published: January 2008

This study was done to determine (a) whether in coronary artery disease (CAD) left ventricular (LV) adaptations differed after 6 months of walking/jogging (legs-only, LO) versus aerobic circuit training (arms and legs, AL) versus a control group, and (b) whether a transfer of fitness to the untrained arms in the LO group was related to superior LV adaptations. Peak oxygen uptake for arm and leg ergometry and for cycle ergometry using radionuclide cardiac angiography were performed before and after training. Leg and arm [Formula: see text] peak increased significantly by 13% in the AL group, and by 13% and 7%, respectively, for the LO group. LV function was greater after training for the LO versus the AL group. Improvements in systolic and diastolic function and a speculated hypervolemia explain these LV adaptations. In CAD patients, walking/jogging produces greater LV function improvements versus circuit training, possibly due to differences in the exercised muscle mass. Key words: cardiac rehabilitation, arm and leg ergometry, end-diastolic volume, stroke volume, radionuclide angiography
Kinetics of Oxygen Uptake for Submaximal Exercise in Hyperoxia, Normoxia, and Hypoxia
Authors: Hughson Richard L. , Kowalchuk John M.
Published: January 2008

This study evaluated the dynamic response of [Formula: see text] in 6 healthy men at the onset and end of submaximal step changes in work rate during a pseudorandom binary sequence (PRBS) exercise test and during ramp incremental exercise to exhaustion while breathing three different gas mixtures. The fractional concentrations of inspired O2 were 0.14, 0.21, and 0.70 for the hypoxic, normoxic, and hyperoxic tests, respectively. Both maximal [Formula: see text] and work rate was significantly reduced in hypoxic tests compared to normoxic and hyperoxic tests. Maximal work rate was greater in hyperoxia than in normoxia. Work rate at ventilatory threshold was lower in hypoxia than in normoxia and hyperoxia but above the upper limit of exercise for the submaximal tests. Hypoxia significantly slowed the response of [Formula: see text] both at the onset and end of exercise compared to normoxia and hyperoxia. Hypoxia also modified the response to PRBS exercise, and again there was no difference between normoxia and hyperoxia. These data support the concept that [Formula: see text] kinetics can be slowed from the normoxic response by a hypoxic gas mixture. Key words: [Formula: see text]max, ventilatory threshold, oxygen deficit, pseudorandom binary sequence
Effects of PNF Stretching Phases on Acute Arterial Blood Pressure
Authors: Cornelius William L. , Jensen Randall L. , Odell Michael E.
Published: January 2008

This study examined acute systolic (SBP) and diastolic (DBP) blood pressure responses within passive and modified proprioceptive neuromuscular facilitation (PNF) stretching techniques. Nonhypertensives (N = 60) were assigned to one of three treatment groups. Group 1 employed an antagonist passive stretch (APS), 6-sec maximal voluntary isometric contraction (MVIC) of the antagonist, and subsequent APS. Group 2 employed an APS, a 6-sec MVIC of the antagonist, submaximal concentric contraction of the agonist, and APS. Group 3 was similar to Group 2, with the deletion of an MVIC prior to the concentric contraction. Blood pressures were obtained during rest, baseline following passive stretch, and at the end of the three phases of the PNF technique. Range of motion (ROM) data were collected for baseline and treatment in terminal hip flexion for each group. All PNF treatments were effective for increasing ROM. One or two trials of PNF improve ROM and avoid increasing SBP, while a third trial increases SBP. Key words: flexibility, nonhypertensives, pressor response, range of motion
Isometric Cervical Extension Strength of Recreational and Experienced Cyclists
Authors: Jacobs Kevin , Nichols Jeanne , Buono Michael , Holmes Bryon
Published: January 2008

The effect for cyclists of the typical forward sitting position on neck strength and its possible relationship to neck pain have not been examined. The purpose of this study was to measure the peak isometric cervical extension strength (PICES) of both recreational and experienced road cyclists and to compare these values to those of noncyclists. Subjects, 45 men between the ages of 18 and 40, were tested for voluntary PICES through a 126° range of motion on a MedX cervical extension machine. No significant differences were found between the three groups in PICES at any angle. When expressed relative to body weight, significant differences in PICES were found at 126° between the control group and the recreational cyclist group (p < 0.05), and between the control group and the experienced cyclist group (p < 0.01), but not at any other angle. Furthermore, no significant differences in strength were found between cyclists experiencing neck pain and those who did not. These data indicate that the cervical muscles of cyclists have not adapted by increasing maximal isometric strength above that of noncyclists, and that the neck pain frequently reported may be due to fatigue from sustained muscular contractions associated with time spent cycling, rather than from muscle weakness. Key words: neck strength, neck pain, muscle fatigue
Cardiovascular Response to Orthostatic Stress: Effects of Exercise Training Modality
Authors: Savard Gabrielle K. , Stonehouse Mark A.
Published: January 2008

The effects of exercise training posture on cardiovascular and baroreflex responses to orthostatic challenge were assessed in highly trained cyclists (CT, n = 8) and swimmers (ST, n = 8), and in untrained men (UT, n = 8). CT demonstrated the lowest orthostatic tolerance to lower body negative pressure (LBNP, 0 to −50 mmHg), with only 3 subjects completing the full LBNP procedure; 5 UT and all ST completed the testing. During LBNP, stroke volume (SV) decreases were similar in CT and ST, but greater than in UT. Mean pulse pressure and systemic vascular resistance (SVR) were reduced in CT relative to ST and UT at the highest levels of LBNP; the slope of the ΔSVR/ΔZ0 and ΔSVR/ΔSV relationships in CT, used to assess peripheral vascular baroreflex function, were attenuated relative to the other groups. There were no between-group differences in the heart rate response to LBNP. The greater incidence of orthostatic intolerance observed in upright-versus supine-trained athletes during passive LBNP was linked to attenuated baroreflex control of peripheral vascular resistance. Key words: arterial baroreflex, arterial pressure, cardiopulmonary baroreceptor, endurance training, vascular resistance
Effects of Fatigue of Rat EDL In Situ on Metabolism of Phosphoinositides
Authors: Oueslati Habib , Gardiner Phillip F.
Published: January 2008

The study was conducted to determine the effect of persistent fatigue in situ on the inositol phosphate second messenger system proposed to constitute a step in excitation-contraction coupling. Rat EDL, after stimulation in situ for 1 hr (100 Hz for 330 ms, 1/s), showed increased incorporation of myo-[3H]inositol into membrane phosphoinositides during a subsequent 4-hr incubation period. The rate of hydrolysis of this pool resulting from 10 sec of tetanic stimulation, as well as the rate of production of inositol phosphates InsP, InsP2, and InsP3, were significantly reduced in fatigued muscles. These results suggest that the metabolic changes that parallel the alteration in contractile response with fatigue reflect a disruption in E-C coupling. Key words: excitation-contraction coupling, inositol phosphates, skeletal muscle
Substrate and Hormonal Responses During Exercise Classes at Selected Stages of Pregnancy
Authors: Bonen Arend , Campagna Philip D. , Gilchrist Louise , Beresford Patricia
Published: January 2008

This study examined the substrate and hormonal responses during exercise classes for 36 pregnant women at selected stages of pregnancy. Six nonpregnant women served as controls. Blood samples were obtained before exercise, at the end of aerobic exercise, and 45 min after aerobic exercise. All samples were analyzed for substrates (glucose, lactate, FFA) and 7 hormones. Heart rates in the pregnant women were ~150 bpm, although some were as high as 180 bpm. Heart rates in the control group were ~130 bpm. Modest increments occurred in lactate and FFA during exercise, and decrements in glucose were observed in all groups. Insulin concentrations decreased with exercise and remained depressed after exercise whereas FFA remained elevated postexercise in the pregnant women. Modest transient changes were observed with exercise in the other hormones. A severely blunted norepinephrine response to exercise was observed in the third-trimester group. In conclusion, uncontrolled non-steady-state exercise does not disrupt the substrate and endocrine milieu markedly. Recovery in hormonal and substrate concentrations appears to occur rapidly after exercise. However, decrements in blood glucose do occur for a short time during prenatal exercise classes, most notably for women in the third trimester Key words: glucose, lactate, FFA, progesterone, estriol, human chorionic gonadotropin
The Effect of an Aerobic Interval Training Program on Intermittent Anaerobic Performance
Authors: Gaiga Milena C. , Docherty David
Published: January 2008

The effects of a 9-week aerobic interval training program on anaerobic intermittent performance were investigated. Intermittent work consisted of four repeat 30-sec maximal efforts on a cycle ergometer (Wingate test) with 3-min recovery intervals. Thirteen men trained 3 days a week on the cycle ergometer, completing 3-min work-to-rest intervals and progressing from 5 to 10 reps. Relative and absolute values of aerobic power increased significantly for the training group (p <.05). No significant change was observed for the control group (n = 11). The training group demonstrated significant increases in the four anaerobic variables of short-term peak power (SPP), short-term anaerobic capacity (SAC), intermediate-term peak power (IPP), and total work (TW), and across the four 30-sec maximal repeats for anaerobic performance (T1-T4) (p <.05). Greater percentages of increase occurred for IPP and TW, especially during Repeats 3 and 4. The control group only demonstrated a significant increase in SPP for Repeat 3. These data suggest that the type of interval training program used in the study increased aerobic power and also enhanced performance in repeated high intensity, short duration work. Key words: short-term peak power, intermediate-term peak power, total work
PHYSARUM MACHINE: IMPLEMENTATION OF A KOLMOGOROV-USPENSKY MACHINE ON A BIOLOGICAL SUBSTRATE
Authors: ADAMATZKY ANDREW
Published: January 2008

We implement a Kolmogorov-Uspensky machine on the Plasmodium of the slime mold Physarum polycephalum. We provide experimental findings on realization of the machine instructions, illustrate basic operations, and elements of programming.
SEIFERT SURFACES, COMMUTATORS AND VASSILIEV INVARIANTS
Authors: KALFAGIANNI E. , LIN XIAO-SONG
Published: January 2008

We show that the Vassiliev invariants of a knot K, are obstructions to finding a regular Seifert surface, S, whose complement looks "simple" (e.g. like the complement of a disc) to the lower central series of its fundamental group. We also conjecture a characterization of knots whose invariants of all orders vanish in terms of their Seifert surfaces.
BIQUANDLE LONGITUDE INVARIANT OF LONG VIRTUAL KNOTS
Authors: NIEBRZYDOWSKI MACIEJ
Published: January 2008

It is known that the number of biquandle colorings of a long virtual knot diagram, with a fixed color of the initial arc, is a knot invariant. In this paper, we construct a more subtle invariant: a family of biquandle endomorphisms obtained from the set of colorings and longitudinal information.
Effect of Plasmapheresis on the Immune System in Endotoxin-Induced Sepsis
Authors: Toft P. , Schmidt R. , Broechner A.C. , Nielsen B.U. , Bollen P. , Olsen K.E.
Published: January 2008

Background: It has been proposed that plasmapheresis is most effective when applied early in Gram-negative sepsis. We therefore studied the effect of early plasmapheresis on immunity in experimental Escherichia coli endotoxin-induced sepsis. Methods: 20 pigs received 30 µg/kg of E. coli endotoxin. 40 min later, half of the pigs were treated with plasmapheresis which lasted 4 h. The adhesion molecules, the oxidative burst, the number of neutrophils in blood and lungs, and cytokines were measured. Results: Infusion of endotoxin was associated with activation of adhesion molecules increased oxidative burst, increased concentration of cytokine, and accumulation of granulocytes in lung tissue. Plasmapheresis reduced the oxidative burst, and there was a tendency towards a reduced accumulation of granulocytes in the lung. Conclusion: Though plasmapheresis was initiated early after the endotoxin infusion, it only temporarily attenuated a part of the activated cell-mediated immunity.
Otologic Manifestations of Hunter Syndrome and Their Relationship with Speech Development
Authors: Cho Yang-Sun , Kim Joon Ho , Kim Tae Wook , Chung Soo Chan , Chang Son-A , Jin Dong-Kyu
Published: January 2008

The excessive storage of mucopolysaccharide in Hunter syndrome leads to various otologic manifestations. We interviewed 19 patients with Hunter syndrome to assess their otologic problems, and conducted audiologic tests and temporal bone CT. Patients with the intermediate or severe form exhibited severe speech delay by more than 2 years (12/14 patients). However, in patients with the mild form (5/5), speech development was not much disturbed (2/5), although otoscopic findings were similar. The hearing threshold determined by the auditory brainstem response differed significantly between the mild and intermediate/severe forms (p < 0.05). Therefore, patients with the mild form may benefit from active otologic intervention such as VT insertion, amplification, and speech therapy.
Clinical Value of the Malnutrition-Inflammation-Atherosclerosis Syndrome for Long-Term Prediction of Cardiovascular Mortality in Patients with End-Stage Renal Disease: A 5-Year Prospective Study
Authors: Akdag Ibrahim , Yilmaz Yusuf , Kahvecioglu Serdar , Bolca Naile , Ercan Ilker , Ersoy Alpaslan , Gullulu Mustafa
Published: January 2008

Background/Aim: Mortality resulting from cardiovascular disease in patients with end-stage renal disease (ESRD) is high. In this study we sought to investigate the clinical value of the malnutrition-inflammation-atherosclerosis (MIA) syndrome for long-term prediction of cardiovascular mortality in patients treated with ESRD. Methods: A total of 42 ESRD patients on hemodialysis were enrolled. Inflammatory markers and nutritional parameters were determined. Carotid atherosclerosis was investigated by ultrasonographically evaluated carotid intima-media thickness (cIMT). Mortality was evaluated at a 5-year follow-up. Results: No correlation was evident between nutritional markers and inflammatory indexes. cIMT was inversely correlated with predialysis serum albumin. In the overall population of 42 patients, 11 (26.2%) died of cardiovascular causes during follow-up. Kaplan-Meier survival curves indicate that cIMT (≧0.9 mm), C-reactive protein (CRP) (>1 mg/dl), and serum albumin (<3.5 g/dl) predict cardiovascular death in patients with ESRD. Conclusions: We have demonstrated that cIMT, CRP and serum albumin predict long-term mortality in ERSD patients. Our study suggests that further investigation of the MIA syndrome will provide insights into the susceptibility to CVD in this patient group.
Transglutaminases in Vascular Biology: Relevance for Vascular Remodeling and Atherosclerosis
Authors: Bakker Erik N.T.P. , Pistea Adrian , VanBavel Ed
Published: January 2008

The transglutaminase (Tgase) family consists of nine known members of whom at least three are expressed in the vascular system: type 1 Tgase, type 2 Tgase and factor XIII. The cross-linking of proteins is a characteristic feature of Tgases, of well-known importance for stabilizing the blood clot and providing mechanical strength to tissues. However, recent data suggest that Tgases play a role in several other processes in vascular biology. These newly discovered areas include endothelial barrier function, small artery remodeling, and atherosclerosis.
Monitoring high-dose heparinization during cardiopulmonary bypass – A comparison between prothrombinase-induced clotting time (PiCT) and two chromogenic anti-factor Xa activity assays
Authors: Kuitunen Anne , Petäjä Jari , Ilveskero Sorella , Lassila Riitta , Raivio Peter
Published: January 2008

Heparinization requires monitoring, but optimal methods for measuring the anticoagulant effects of heparin remain to be determined. We compared prothrombinase-induced clotting time (PiCT) and two chromogenic anti-factor Xa activity (anti-Xa) assays in monitoring high-dose heparinization during cardiopulmonary by-pass (CPB). Heparin effects were serially measured with PiCT and two anti-Xa assays in 100 patients. Antithrombin and protein C activities were measured preoperatively, and antithrombin activity was measured during CPB. Activation of coagulation was assessed with measurements of prothrombin fragment F1+2, soluble fibrin complexes, and D-dimer before, during, and after CPB. During CPB mean ranges of PiCT and of anti-Xa heparin levels measured with (anti-Xa A) and without (anti-Xa B) dextran sulfate and antithrombin supplementation were 5.0–5.2, 4.7–5.0, and 4.5–4.9 IU/ml, respectively. There was poor agreement between PiCT and anti-Xa and between the two anti-Xa assays (r=0.32–0.65 and broad limits of agreement). Patients with low preoperative antithrombin or protein C levels had lower PiCT (p=0.028 and p=0.01) and anti-Xa A (both p<0.001) levels during CPB than others. Patients with the lowest heparin activities during CPB (lowest deciles of PiCT and anti-Xa A) had higher subsequent F1+2 after CPB (p=0.002 and p=0.02), and patients with high heparin levels required fewer transfusions of packed red blood cells than others. In conclusion, in the challenging setting of CPB there is poor agreement between anti-Xa assays and PiCT. However, coagulation-based PiCT could provide an alternative to the chromogenic anti-Xa assays. Higher heparin levels during CPB were confirmed to associate with reduced transfusion requirements.
Stability of coagulation assays performed in plasma from citrated whole blood transported at ambient temperature
Authors: Zürcher Manuel , Sulzer Irmela , Barizzi Gabriela , Lämmle Bernhard , Alberio Lorenzo
Published: January 2008

Many preanalytical variables affect the results of coagulation assays. A possible way to control some of them would be to accept blood specimens shipped in the original collection tube. The aim of our study was to investigate the stability of coagulation assays in citrated whole blood transported at ambient temperature for up to two days after specimen collection. Blood samples from 59 patients who attended our haematology outpatient ward for thrombophilia screening were transported at ambient temperature (outdoor during the day, indoor overnight) for following periods of time: <1 hour, 4–6, 8–12, 24–28 and 48–52 hours prior to centrifugation and plasma-freezing. The following coagulation tests were performed: PT, aPTT, fibrinogen, FII:C, FV:C, FVII:C, FVIII:C, FIX:C, FX:C, FXI:C,VWF:RCo,VWF:Ag, AT, PC activity, total and free PS antigen, modified APC-sensitivity-ratio, thrombin-antithrombin-complex and D-dimer. Clinically significant changes, defined as a percentage change of more than 10% from the initial value, were observed for FV:C, FVIII:C and total PS antigen starting at 24–28 hours, and for PT, aPTT and FVII:C at 48–52 hours. No statistically significant differences were seen for fibrinogen, antithrombin, or thrombin-antithrombin complexes (Friedman repeated measures analysis of variance).The present data suggest that the use of whole blood samples transported at ambient temperature may be an acceptable means of delivering specimens for coagulation analysis. With the exception of factorV andVIII coagulant activity, and total PS antigen all investigated parameters can be measured 24–28 hours after specimen collection without observing clinically relevant changes.
Construction and functional evaluation of hirudin derivatives with low bleeding risk
Authors: Yuan Bin , Dong Chunna , Yu Hongyang , Wang Lisheng , Zhang Chuanling , Yu Aiping , Wu Chutse
Published: January 2008

The purpose of this study was to design and evaluate hirudin (HIR) derivatives with low bleeding risk. In these derivatives, the factor (F) XIa, FXa, and thrombin recognition peptides (EPR, GVYAR, and LGPR, respectively) were linked to the N-terminus of HIR. The intact derivatives have no anticoagulant activity because of the extension of the N-terminus of HIR. After cleavage by the corresponding coagulation factor that occurs on the activation of the coagulation system and in the presence of the thrombus, its activity is released. This limited the anticoagulant activity of these derivatives to the vicinity of the thrombus, and as a result, systemic bleeding complications were avoided. The definite antithrombotic effect and low bleeding parameters of these derivatives were investigated in rat carotid artery and inferior vena cava thrombosis models. In both models, the three derivatives showed significant antithrombotic effects, indicating that anticoagulant activity could be successfully released in vivo. Moreover, the bleeding parameters of these derivatives were lower than that of HIR as indicated by the values of activated partial thromboplastin time (APTT) and thrombin time (TT). To further assess the safety of these derivatives, bleeding time was measured in a mouse tail-cut model. Although the derivatives had obvious effects on bleeding at a dose of 6 mg/kg, the effect of these derivatives on bleeding was significantly weaker than that of HIR at a dose of 1.5 mg/kg. Thus, the benefit-to-risk profiles of the derivatives were superior to that of HIR.
Congenital disorders associated with platelet dysfunctions
Authors: Nurden Paquita , Nurden Alan T.
Published: January 2008

Genetic defects of the megakaryocyte lineage give rise to bleeding syndromes of varying severity. Blood platelets are unable to fulfill their hemostatic function of preventing blood loss on vessel injury. Spontaneous bleeding is mostly mucocutaneous in nature. Most studied are deficiencies of glycoprotein (GP) mediators of adhesion (Bernard-Soulier syndrome) and aggregation (Glanzmann thrombasthenia) which concern the GPIb-IX-V complex and the integrin αIIbβ3, respectively. Defects of primary receptors for stimuli include the P2Y12 ADP receptor pathology. Agonist-specific deficiencies in the platelet aggregation response and abnormalities of signaling pathways are common and lead to trauma-related bleeding. Inherited defects of secretion from storage organelles, of ATP production, and of the generation of procoagulant activity are also encountered. In some disorders, such as the Chediak-Higashi, Hermansky-Pudlak, Wiskott-Aldrich and Scott syndromes, the molecular lesion extends to other cells. In familial thrombocytopenia (FT), platelets are produced in insufficient numbers to assure haemostasis. Some of these disorders affect platelet morphology and give rise to the so-called ‘giant platelet’ syndromes (MYH9-related diseases) with changes in megakaryocyte maturation within the bone marrow and premature release of platelets. Diseases of platelet production may extend to other cells and in some cases interfere with development. Transfusion of platelets remains the most common treatment of severe bleeding, management with desmopressin is common for mild disorders. Substitute therapies are available including rFVIIa and the potential use of TPO analogues for FT. Stem cell or bone marrow transplanation is being used for severe diseases while gene therapy may be on the horizon.
Prophylactic P-selectin inhibition with PSI-421 promotes resolution of venous thrombosis without anticoagulation
Authors: Myers Daniel D. , Wrobleski Shirley K. , Zajkowski Paul J. , Hawley Angela E. , Bedard Patricia W. , Ballard Nicole E. , Londy Frank J. , Kaila Neelu , Vlasuk George P. , Wakefield Thomas W. , Meier Thomas R. , Schaub Robert G.
Published: January 2008

P-selectin inhibition has been evaluated as a therapeutic for prevention and treatment of venous thrombosis. In this study, a novel oral small-molecule inhibitor of P-selectin, PSI-421, was evaluated in a baboon model of stasis induced deep vein thrombosis (DVT). Experimental groups included i) primates receiving a single oral dose of 1 mg/kg PSI-421 two days prior and continued six days after thrombosis (n=3); ii) primates receiving a single daily subcutaneous dose of 0.57 mg/kg enoxaparin sodium two days prior and continued six days post thrombosis (n=3); and iii) primates receiving no treatment (n=3).PSI-421 treated primates had greater percent vein reopening and less vein wall inflammation than the enoxaparin and controls at day 6. Microparticle tissue factor activity (MPTFA) was significantly lower in the animals receiving PSI-421 immediately after thrombosis (T+6 hours day 0) suggesting lower potential for thrombogenesis in these animals. PSI-421 also reduced soluble P-selectin levels versus controls at T+6 hours day 0, day 2 and 6. Experimental animals in any group showed no adverse effects on coagulation. This study is the first to demonstrate a reduction in MPTFA associated with vein reopening and reduced vein inflammation due to oral P-selectin inhibition in a baboon model of DVT.
How to optimise clopidogrel therapy? Reducing the low-response incidence by aggregometry-guided therapy modification
Authors: Lask Sebastian , Engelhardt Andreas , Mügge Andreas , Neubauer Horst
Published: January 2008

The inhibitory platelet effect of clopidogrel is insufficient in approximately 5 to 30% of patients. These low responders (LR) face a significantly higher risk of cardiovascular complications. The therapeutic management of LR is still undefined. In the present study, we evaluate a novel therapeutic algorithm to reduce the incidence of clopidogrel resistance. One hundred sixty-one patients on 100 mg ofAspirin co-medication underwent elective coronary stenting and were given an initial dosage of 600 mg clopidogrel, followed by 75 mg clopidogrel daily. 48 h later, the platelet responsiveness was tested with ADP (5–20 μM) stimulation by impedance aggregometry (Chronolog 590). A significant rise in impedance (> 5 Ω after 6 minutes, aggregation index > 65%) was defined as LR. In this subgroup, platelets were stimulated with the selective P2Y12-ADP receptor antagonist 2-MeS AMP. One hundred twenty-three patients were clopidogrel-responders (76.4%) and 38 patients were LR (23.6%). A defect of the ADP-receptor P2Y12 was found in three out of 38 LR (7.9%). Inhibition of platelet aggregation indicating clopidogrel-responsiveness was achieved with either a clopidogrel high-dose regimen (22/38, 57.9%); a repeat loading dose, doubling the maintenance dose) or with an alternative therapy with ticlopidine (8/38 (21.1%); 250 mg twice daily).Thus the incidence of LR was reduced from 23.6% to 5.0%. Our aggregometer–guided therapeutic algorithm reduced the relative percentage of clopidogrel LR by 78.9%.This approach could prove to be helpful in achieving a further decrease in the incidence of clopidogrel resistance.
Targeting phosphoinositide 3-kinase γ to fight inflammation and more
Authors: Barberis Laura , Hirsch Emilio
Published: January 2008

The family of class I phosphoinositide-3-kinase (PI3K) is composed of four lipid kinases involved at multiple levels in innate and adaptive immune responses. Class I PI3Ks are divided into two subclasses, IA and IB, sharing a similar catalytic core. Whereas class IA PI3Ks are primarily activated by receptor tyrosine kinases, the unique element of class IB PI3K (PI3Kγ) is activated by G protein coupled receptors (GPCRs), like chemokine receptors. PI3Kγ is mainly expressed in leukocytes where it plays a significant role in chemotaxis. Here, we report recent advances in the analysis of the role of PI3Kγ in leukocytes and in endothelial cells. Results, derived from studies based on both pharmacological and genetic approaches, confirm PI3Kγ as an attractive target for drug discovery. PI3Kγ specific inhibition has gained increasing attention for the treatment of allergic, autoimmune and inflammatory diseases. Development of inhibitors has already provided series of hits, whose efficacy is currently under scrutiny worldwide.