The seeds of invasion: enhanced germination in invasive European populations of black locust (Robinia pseudoacacia L.) compared to native American populations.

Local adaptation and the evolution of phenotypic plasticity may facilitate biological invasions. Both processes can enhance germination and seedling recruitment, which are crucial life-history traits for plants. The rate, timing and speed of germination have recently been documented as playing a major role during the invasion process. Black locust (Robinia pseudoacacia L.) is a North American tree, which has spread widely throughout Europe. A recent study demonstrated that a few populations are the source of European black locust. Thus, invasive populations can be compared to native ones in order to identify genetic-based phenotypic differentiation and the role of phenotypic plasticity can thereby be assessed. A quantitative genetics experiment was performed to evaluate 13 juvenile traits of both native and invasive black locust populations (3000 seeds, 20 populations) subjected to three different thermal treatments (18 °C, 22 °C and 31 °C). The results revealed European populations to have a higher germination rate than the native American populations (88% versus 60%), and even when genetic distance between populations was considered. Moreover, this trait showed lower plasticity to temperature in the invasive range than in the native one. Conversely, other studied traits showed high plasticity to temperature, but they responded in a similar way to temperature increase: the warmer the temperature, the higher the growth rate or germination traits values. The demonstrated genetic differentiation between native and invasive populations testifies to a shift between ranges for the maximum germination percentage. This pattern could be due to human-mediated introduction of black locust.

Efectos hipoalgésicos y de movilidad cervical tras la manipulación vertebral cervical o la manipulación vertebral dorsal en pacientes con cervicalgia mecánica subaguda: estudio piloto / Hypoalgesic and cervical motion effects after a cervical spine or thoracic spine manipulation in subjects with subacute mechanical neck pain: a pilot study

Objetivo Comparar el efecto en el dolor, movilidad cervical y umbral de dolor a la presión después de una manipulación vertebral cervical o dorsal en pacientes con cervicalgia mecánica subaguda. Métodos Se realizó un estudio piloto aleatorizado a simple ciego. Los pacientes fueron asignados aleatoriamente dentro del grupo de manipulación cervical (n=9) o al grupo de manipulación dorsal (n=9). Las variables medidas fueron el dolor en reposo del paciente (escala visual analógica), rango de movilidad cervical y el umbral de dolor a la presión, antes y 5min después de la intervención por un evaluador ciego. Las comparaciones intragrupales e intergrupales se realizaron con el análisis de varianza (ANOVA) y la prueba de la t de Student. Resultados Dieciocho pacientes, 7 varones y 11 mujeres, con dolor mecánico subagudo de cuello participaron en el estudio. Los cambios intragrupales mostraron una mejora estadísticamente significativa en el dolor de cuello, movilidad cervical y los umbrales de dolor a la presión en ambos grupos (p<0,05). La comparación inter-grupal del efecto no mostró diferencias significativas entre los grupos en ninguna de las variables medidas (p>0,05). Por tanto, ambos grupos mostraron una mejoría similar en las variables. Conclusiones Nuestros resultados sugieren que una manipulación cervical y dorsal produce un efecto similar en la disminución del dolor e incremento del rango de movilidad activo y umbrales de dolor mecánico en pacientes con cervicalgia mecánica subaguda. Se necesitan ensayos clínicos aleatorizados con una muestra de pacientes mayor para confirmar nuestros resultados (AU)

Purpose To compare the immediate effects on neck pain, active cervical range of motion and pressure pain thresholds after a single cervical or thoracic spine manipulation in patients with subacute mechanical neck pain. Methods A randomized single-blinded pilot study was conducted. Subjects were divided randomly into either a cervical spine manipulation group (n=9) or a thoracic spine manipulation group (n=9). Outcome measures were neck pain at rest (visual analogue scale), active cervical range of motion and pressure pain thresholds over C5-C6 zygapophyseal joints and both lateral epicondyles, before treatment and 5minutes after treatment by an assessor blinded to the treatment allocation. Intragroup and intergroup comparisons were made with different analyses of variance (ANOVA) and the T-student test. Results Eighteen patients, 7 males and 11 females, with subacute mechanical neck pain participated. Within-group changes showed a significant improvement in neck pain, cervical mobility and pressure pain thresholds in both groups (p<.05). The intergroup comparison did not show significant differences between either manipulative group s in any of the measures (p>.05). Therefore, both groups exhibited similar improvements in the outcomes. Conclusions Our results suggest that a single cervical spine manipulation or a single thoracic thrust spine manipulation produce similar effects in reducing neck pain at rest and in increasing active cervical range of motion and segmental pressure pain thresholds in individuals with sub-acute mechanical neck pain. Future randomized clinical trials with greater sample sizes are now needed to further confirm our results (AU)

L-tryptophan supplementation can decrease fatigue perception during an aerobic exercise with supramaximal intercalated anaerobic bouts in young healthy men.

Physical exercise is often terminated not due to muscle fatigue but because of inadequate neural drive in the serotonergic system. Modifications in activity levels of the serotonergic system, induced by variations in the availability of L-tryptophan (a serotonin precursor) may alter neural drive. We examined the effect of L-tryptophan supplementation on physical performance by combining aerobic work with brief periods of supramaximal intensity that closely mimics the activity typical of team sports. Twenty healthy young sportsmen (mean age 21.2 +/- 0.7 years) performed a submaximal exercise on a cycle ergometer, with a workload corresponding to 50% of their respective VO(2) max for 10 min, followed by a maximal intensity exercise for 30 s. This sequence was repeated three times and, after the fourth series, each participant continued to exercise at the highest speed that he could sustain for 20 min. This protocol was performed twice: once with and finally without supplementation of L-tryptophan, in random order and double-blind. Peak power output, average anaerobic power output, and power output during the last 20 min of the trial were higher on the trials performed with L-tryptophan supplementation than on those performed with placebo. The distance covered during the last 20 min of the trial was 11,959 +/- 1,753 m on placebo and 12,526 +/- 1,617 m on L-tryptophan (p < .05). In conclusion, in some types of exercises, modification of the serotonergic system may improve the physical performance.

The effect of supplementation wit n-3 fatty acids on the physical performance in subjects with spinal cord injury

A global physical evaluation was performed in 21 males with spinal cord injury (SCI), at the beginning and at three and six months of omega-3 fatty acid (FA) supplementation. A significant increase in the proportion of eicosapentaenoic acid and docosahexanoic acid in plasma was observed in response to the supplementation (p<0.05). After six months of FA supplementation, strength endurance time increased from 127.7±19.0 s to 215.2±45.6 s in the right arm, and from 139±27.6 s to 237.7±48.7 s, in the left arm. The time to perform 20 repetitions of 70% maximum workload showed a reduction of 41% between the first and the third test. The time taken to cover a 90 meter long track, with a 6% slope, was reduced from 66.9±8.0 s to 59.3±6.7 s, at the end of the study (p<0.05). In conclusion, omega-3 FA supplementation could contribute to improve the functional capabilities in SCI subjects (AU)

Se ha realizado una evaluación global a 21 sujetos con lesión medular al inicio, tras tres meses y a los seis meses de la ingesta de un suplemento de ácidos grasos n-3. Se observó un aumento estadísticamente significativo de la proporción de ácido eicosapentanóico y ácido docosahexaenóico en plasma como respuesta a la ingesta del suplemento (p<0,05). Tras seis meses del suplemento de ácidos grasos n-3, el tiempo de resistencia a la fuerza aumentó de manera significativa desde 127,7±19,0 s a 215,2±45,6 s en el brazo derecho, y desde 139±27,6 s hasta 237,7±48,7 s en el brazo izquierdo. El tiempo para realizar 20 repeticiones contra el 70% de la máxima carga realizada mostró una reducción del 41% entre el primer (al inicio del estudio) y el tercer test (tras seis meses de suplemetno). El tiempo para recorrer una distancia de 90 metros, con un 6% de pendiente, se redujo de 66,9±8,0 s a 59,3±6,7 s al final del estudio (p<0,05). En conclusión, la suplementación con ácidos grasos n-3 puede contribuir a mejorar la capacidad funcional en lesionados medulares (AU)

The effect of supplementation with n-3 fatty acids on the physical performance in subjects with spinal cord injury.

A global physical evaluation was performed in 21 males with spinal cord injury (SCI), at the beginning and at three and six months of omega-3 fatty acid (FA) supplementation. A significant increase in the proportion of eicosapentaenoic acid and docosahexanoic acid in plasma was observed in response to the supplementation (p<0.05). After six months of FA supplementation, strength endurance time increased from 127.7+/-19.0 s to 215.2+/-45.6 s in the right arm, and from 139+/-27.6 s to 237.7+/-48.7 s, in the left arm. The time to perform 20 repetitions of 70% maximum workload showed a reduction of 41% between the first and the third test. The time taken to cover a 90 meter long track, with a 6% slope, was reduced from 66.9+/-8.0 s to 59.3+/-6.7 s, at the end of the study (p<0.05). In conclusion, omega-3 FA supplementation could contribute to improve the functional capabilities in SCI subjects.

Continual supplementation with n-3 fatty acids does not modify plasma lipid profile in spinal cord injury patients.

STUDY DESIGN: A prospective study during a diet modification. OBJECTIVE: To observe the evolution of the plasma lipid profile in a group of spinal cord injury (SCI) patients given a supplement of a mixture of docosahexanoic acid (DHA) and eicosapentaenoic acid (EPA). SETTING: Department of Physiological Sciences II, Medical School of the University of Barcelona and Guttmann Institut of Badalona, Barcelona, Spain. METHODS: A total of 19 adult males with SCI, 17 with paraplegia and two with tetraplegia, were given a daily supplement of 1.5 g of DHA and 0.75 g of EPA for 6 months. Determination of plasma values of DHA, EPA, total cholesterol, HDL-c, LDL-c, VLDL-c, triglycerides, and glucose was performed before supplementation and at 3 and 6 months of supplementation. RESULTS: A statistically significant increase in the plasma concentration of EPA (F=30.556, P<0.05) and DHA (F=106.6, P<0.05) was observed after 3 and 6 months of supplementation. However, there were no observable differences in the plasma concentration of total-cholesterol, HDL-c, LDL-c, VLDL-c, and triglycerides during the study. CONCLUSION: DHA-EPA supplementation for 6 months does not modify the glycemic and lipid plasmatic levels in SCI patients. Despite its absence of effect on the serum lipid profile, n-3 fatty acids may induce beneficial cardiovascular effects in this population.

Creatine supplementation and performance in 6 consecutive 60 meter sprints.

Creatine is an ergogenic aid used in individual and team sports. The aim of this study is to analyze the effect of monohydrate creatine supplementation on physical performance during 6 consecutive maximal speed 60 meter races, and the changes induced in some characteristic biochemical and ventilatory parameters. The study was carried out on nineteen healthy and physically active male volunteers, and randomly distributed into two groups: Group C received a supplement of creatine monohydrate (20 g/day for 5 days) and group P received placebo. Tests were performed before and after supplementation. No significant changes were observed in weight or body water measured by bioimpedance or the sum of 7 skinfold or performance during the 60 meter races. Group C showed a statistically significant increase in plasma creatinine from 69.8 +/- 12.4 to 89.3 +/- 12.4 micromol x L(-1) (p<0.05). In group C in the second control day (after creatine supplementation), expiratory volume V(E), O2 uptake and CO2 production were lower after 2 minutes of active recovery period. These results indicate that creatine monohydrate supplementation does not appear to improve the performance in 6 consecutive 60 meter repeated races but may modify ventilatory dynamics during the recovery after maximal effort.

Plant-growth inhibitory activity of cedrelanolide from Cedrela salvadorensis.

The effect of cedrelanolide, the most abundant limonoid isolated from Cedrela salvadorensis (Meliaceae), was assayed as a plant-growth inhibitory compound against monocotyledonous and dicotyledonous seeds. This compound inhibited germination, seed respiration, and seedling dry weights of some plant species (Lolium multiflorum, var. Hercules, Triticum vulgare, var. Salamanca, Physalis ixocarpa, and Trifolium alexandrinum). Our results indicate that cedrelanolide interferes with monocot preemergence properties, mainly energy metabolism of the seeds at the level of respiration. In addition, the compound inhibits photophosphorylation, H+ uptake, and noncyclic electron flow. This behavior might be responsible for its plant-growth inhibitory properties and its possible role as an allelopathic agent.

Fish consumption, omega-3 fatty acids and the Mediterranean diet.

Many epidemiological, interventional and animal studies have concluded that consumption of polyunsaturated fatty acids of marine origin may confer special benefits in reducing cardiovascular heart disease (CHD) mortality rates by different physiological mechanisms. The available epidemiological data, although limited, suggest that a dietetic recommendation on the consumption of one or two servings per week (200-300 g = 2-4 g eicosapentaenoic acid) of cold water marine fish could lead to a reduction of the CHD risk. Nevertheless, there are important methodological shortcomings and contradictory findings in most published investigations on the omega-3 fatty acids. In order to assess the role of fish consumption in the Mediterranean diet, we have compared data on average fish and fatty fish consumption trends in some Mediterranean (Spain, Yugoslavia and Italy) and northern European (Norway, Denmark) countries. Fish consumption is not positively correlated with ischaemic heart disease mortality. That suggests that dietary factors other than fish, such as the lower meat consumption associated to the higher fish intake, or other differences of lifestyle have perhaps intervened, helping to explain the healthy nature of the Mediterranean diet.

Rat myocardial tissue lipids and their effect on ventricular electrical activity: influence on dietary lipids.

OBJECTIVE: The aim was to investigate the effect of diets with different lipid content on rat myocardial tissue lipid composition and their possible influence on myocardial electrical activity. METHODS: 60 male Sprague-Dawley rats were randomised in three dietary feeding groups. Half the animals were used for the myocardial lipid study and the other half for the ventricular refractory period and ventricular conduction velocity measurements. Synthetic diets of low fat, high fat (predominantly lard fat), and high fat plus marine oil, the last two with cholesterol, were supplied ad libitum for five weeks. After 2-propanol myocardial lipid extraction, lipid fractions were separated by thin layer chromatography and their esterified fatty acids by gas-liquid chromatography. Ventricular refractory period was obtained according to the extrastimulus technique and maximum conduction velocity by ventricular pacing. RESULTS: The experimental diets induced marked changes in fatty acid composition of myocardial phospholipids and in esterified cholesterol content. The high fat group showed a significant decrement in oleic and linoleic acids, with an increment in arachidonic and docosahexaenoic acids in their phospholipid composition. This dietary group had the highest esterified cholesterol content. These changes were related to lowering of maximum ventricular paced heart rate and lengthening of ventricular refractory period, and were partly corrected by marine oil supplement. CONCLUSIONS: Saturated fat diets cause profound changes in myocardial fatty acyl composition which are linked to sustained differences in myocardial electrical activity. These changes can be partly corrected by a moderate fish oil supplement.

Preparation of fatty acid methyl esters by direct transesterification of lipids with aluminium chloride-methanol.

A new and simple procedure has been developed that allows the direct transesterification of lipids, using aluminium chloride as a catalyst and methanol as the esterifying alcohol. The concentration of the salt and reaction conditions have been investigated for the different lipid classes. Comparative studies, performed with boron trifluoride-methanol, indicate that the same values are obtained when using either reagent. In addition, the method has been adapted for transesterification in the presence of silica gel and other adsorbents, thus allowing the preparation of fatty acid methyl or ethyl esters directly from samples previously fractionated by thin-layer chromatography. This new reagent is very stable and easy to handle, the fatty acids being generated in the same tube without further purification steps.

Contrasting effects on plasma lipoproteins of intravenous versus oral administration of a triglyceride-phospholipid emulsion.

The effect of fat on plasma lipoproteins was compared when administered by the oral and intravenous routes to healthy control subjects on a low fat diet for 5-6 weeks. During this time each subject underwent two 5 day periods of fat supplementation with a soya bean triglyceride-egg yolk phospholipid emulsion (Intralipid), once via intragastric tube, once intravenously. Changes in plasma lipoproteins were assessed by measurement of their lipid and protein content. Intragastric fat administration significantly decreased the level of very low density lipoprotein (VLDL), whereas intravenous fat administration caused a significant rise in low density lipoprotein (LDL). Morphological evidence of persistence of exogenous phospholipid in plasma following intravenous fat administration was confirmed by alterations in the fatty acid composition of lecithin in the d 1.006-1.063 fraction of plasma. In vitro studies showed that exchange readily occurred between Intralipid and LDL lecithin, causing the latter to assume a more saturated pattern. It is concluded that the occurrence of similar changes in vivo could explain the rise in low density lipoprotein following intravenous fat, possibly by influencing the catabolic rate of the apoprotein. Hydrolysis of ingested phospholipids during absorption presumably explains why none of these changes occurred after oral fat supplementation, and would seem to be an important regulatory function of the small intestine in relation to plasma lipoprotein metabolism.