A simulação da biomassa de aveia por elementos climáticos, nitrogênio e regulador de crescimento / The simulation of the oat biomass by climatic elements, nitrogen and growth regulator

A produção de biomassa de aveia voltada à elaboração de silagem de qualidade é dependente de elementos climáticos e nitrogênio sem ocorrência de acamamento. O objetivo do presente estudo é a definição da dose ideal do regulador de crescimento que possibilite, no máximo, 5% de acamamento de plantas de aveia, bem como a identificação das variáveis potenciais para composição do modelo de regressão linear múltipla com simulação da produtividade de biomassa à elaboração de silagem nas condições de uso do regulador, em reduzida, alta e muito alta fertilização com nitrogênio. O estudo foi conduzido em 2013, 2014 e 2015, em delineamento de blocos ao acaso, com quatro repetições em esquema fatorial 4x3, para doses de regulador (0, 200, 400 e 600mL ha-1) e doses de nitrogênio (30, 90 e 150kg ha-1), respectivamente. A dose de 495mL ha-1 de regulador se mostra eficiente na redução do acamamento de plantas de aveia em condição de reduzida, alta e muito alta fertilização com nitrogênio. A soma térmica, a precipitação, a radiação, a dose de regulador e o nitrogênio qualificam a composição do modelo de regressão linear múltipla, tornando eficiente a simulação da produtividade de biomassa da aveia para silagem ao longo do ciclo.(AU)

The production of oat biomass focused on the development of quality silage is dependent on climatic elements and nitrogen without lodging occurrence. The objective of the study is to define the optimal dose of growth regulator that allows a maximum of 5% oat plant lodging and identify potential variables for composition of multiple linear regression model with productivity simulation of biomass to the preparation of silage in the conditions of low, high and very high fertilization with nitrogen. The study was conducted in 2013, 2014, and 2015 in the randomized block design with four replications in a factorial 4x3, for regulator doses (0, 200, 400 and 600ml ha-1) and nitrogen doses (30, 90 and 150kg ha-1), respectively. The dose of 495mL ha-1 regulator is efficient in reducing the oat plant lodging in condition reduced, high, and very high fertilization with nitrogen. Thermal time, precipitation, radiation, regulator dose and nitrogen dose qualify the composition of the multiple linear regression model, making efficient the biomass oat productivity simulation for silage over the cycle.(AU)

Repeated blast exposure alters open field behavior recorded under low illumination.

Blast-induced traumatic brain injury (bTBI) can have devastating behavioral consequences. This study was designed to evaluate the behavioral consequences of single or repeated bTBI, as evaluated by an open field (OF) test conducted in near-darkness to avoid confounding effects of illumination and photophobia. Sprague-Dawley rats under isoflurane anesthesia were exposed to a series of 3 sub-lethal blasts into a compressed air-driven blast chamber separated by 2 week intervals (n=11). Sham controls received anesthesia but without blast exposure (n=11). OF tests were performed 1 or 7 days after each blast using a computerized video tracking system in near-darkness to monitor spontaneous activity. Spatial and temporal variables calculated for both blast and sham groups were: Distance moved (cm) and time (s) spent in the center or periphery zones of the field, total distance traveled, speed in center and periphery zones, rearing events and non-linear regressions of distance moved and rearing events on time. Results showed that the sham group expressed the expected decrease (habituation) in total distance walked, and distance walked as well as speed in center and periphery in successive exposures to the OF while the blast group did not, a sign of impaired learning. The blast group also walked more and faster and demonstrated more rearing behavior, both considered OF signs of anxiety. These results indicate that OF outcomes of bTBI in animals have resemblance to alterations observed in human subjects with this condition and might be useful in evaluating the response of behavioral outcomes of bTBI to experimental treatments.

Acetylcholinesterase inhibition interacts with training to reverse spatial learning deficits after cortical impact injury.

Cholinergic mechanisms are known to play a key role in cognitive functions that are profoundly altered in traumatic brain injury (TBI). The present investigation was designed to test the ability of continuous administration, starting at the time of injury, of physostigmine (PHY), an acetylcholinesterase (AChE) inhibitor that crosses the blood-brain barrier (BBB), to ameliorate the alterations of learning and memory induced by cerebral cortex impact injury in rats under isoflurane anesthesia. Learning and memory were assessed with the Morris water maze implemented during days 7-11 (WM1), and days 21-25 post-TBI (WM2), with four trials per day for 3 days, followed by target reversal and 2 additional days of training. These groups of Sprague-Dawley male rats were used: TBI treated with PHY at 3.2 µmol/kg/day (TBI-PHY3.2), or 6.4 µmol/kg/day (TBI-PHY6.4), by subcutaneous osmotic pumps, or TBI and no injury (Sham) treated with saline. AChE activity was measured in brain tissue samples of non-traumatized animals that received PHY at the doses used in the TBI animals. In WM1 tests, PHY3.2 improved learning within sessions, but not between sessions, in the recall of the target position, while PHY6.4 had no significant effects. In WM2 tests, PHY improved within- and between-sessions performance at both dose levels. We found that continuous AChE inhibition interacted with repeated training on the water maze task to completely reverse the deficits seen in learning and memory induced by TBI. The PHY treatment also reduced the amount of brain tissue loss as measured using cresyl violet staining.

Calf tissue oxygenation during exercise in men with and without risk factors for developing peripheral arterial disease.

OBJECTIVE: This study aimed to compare calf tissue oxygenation responses to calf exercise in men without diagnosed peripheral arterial disease but with selected risk factors for peripheral arterial disease with those without risk factors. DESIGN: A cross-sectional quasi-experimental design was used. The no-risk group (n = 20) had none of the risk factors (diabetes, hypertension, hyperlipidemia, obesity, current or 10 pack-yr smoking history, or age ≥65 yrs). The at-risk group (n = 45) had one to six risk factors. Medial calf tissue oxygenation (percentage saturation) was determined using near-infrared spectroscopy during seven consecutive 5-min test stages: rest, 0-W active plantar/dorsiflexion, rest, 4-W resistive plantar flexion, rest, 8-W resistive plantar flexion, and rest. Resistive exercise was performed on the Stresst'er calf ergometer. RESULTS: Compared with the no-risk group, decrements in calf tissue oxygenation induced by light-to-moderate resistive calf exercise in the at-risk group was significantly greater (by 9% saturation) (4-W: P < 0.001; 8-W: P = 0.002). CONCLUSIONS: Men with risk factors for developing peripheral arterial disease but without such diagnosis demonstrated greater decrements in calf tissue oxygenation during calf exercise compared with men without risk factors. Further development of this test may lead to early diagnosis and intervention to modify risk factors and prevent co-morbidities.

Robot-assisted upper-limb therapy in acute rehabilitation setting following stroke: Department of Veterans Affairs multisite clinical trial.

This randomized, controlled, multisite Department of Veterans Affairs clinical trial assessed robot-assisted (RA) upper-limb therapy with the Mirror Image Movement Enabler (MIME) in the acute stroke rehabilitation setting. Hemiparetic subjects (n = 54) received RA therapy using MIME for either up to 15 hours (low-dose) or 30 hours (high-dose) or received up to 15 hours of additional conventional therapy in addition to usual care (control). The primary outcome measure was the Fugl-Meyer Assessment (FMA). The secondary outcome measures were the Functional Independence Measure (FIM), Wolf Motor Function Test, Motor Power, and Ashworth scores at intake, discharge, and 6-month follow-up. Mean duration of study treatment was 8.6, 15.8, and 9.4 hours for the low-dose, high-dose, and control groups, respectively. Gains in the primary outcome measure were not significantly different between groups at follow-up. Significant correlations were found at discharge between FMA gains and the dose and intensity of RA. Intensity also correlated with FMA gain at 6 months. The high-dose group had greater FIM gains than controls at discharge and greater tone but no difference in FIM changes compared with low-dose subjects at 6 months. As used during acute rehabilitation, motor-control changes at follow-up were no less with MIME than with additional conventional therapy. Intensity of training with MIME was positively correlated with motor-control gains.

Ergometric performance during exercise training in men with intermittent claudication.

OBJECTIVE: To determine and describe changes in weekly work, power, exercise times, and recovery times during an exercise training intervention in men with peripheral arterial disease (PAD) and intermittent calf claudication. DESIGN: Tracking of weekly exercise training parameters involved repeated measures over time in one group of participants. Other outcomes of this pilot study used a one-group, pretest-posttest design. SETTING: Tertiary-care medical center. PARTICIPANTS: Fifteen male veterans (mean age, 69 years) with Fontaine stage IIa PAD and classic intermittent calf claudication. MAIN OUTCOME MEASUREMENTS: Participants completed graded treadmill exercise tests before and after intervention from which maximal walking power was calculated. Work, power, and exercise and recovery times for each exercise training session were computed and averaged for each week. INTERVENTION: The intervention consisted of an intensive 3-month exercise training program involving walking and calf muscle exercises: 3 sessions per week at the clinic (treadmill walking and calf ergometry) and 2 sessions per week at home (free walking and standing heel raises). RESULTS: After training, participants increased treadmill maximal walking power from 220 to 414 W (by 87%). Treadmill and calf exercise work, power, and exercise time per session increased linearly during 13 weeks of training, whereas recovery time per session of treadmill exercise decreased. During the same period, treadmill and calf exercise training power outputs increased by averages of 227% and 92%, respectively. CONCLUSION: Calculation of work and power during exercise training can be used to track progress quantitatively at short intervals. Weekly linear increases in training work and power per exercise session suggest that optimal intervention duration may be longer than 3 months for men with PAD and intermittent calf claudication.

Preamputation evaluation of lower-limb skeletal muscle perfusion with H(2) (15)O positron emission tomography.

OBJECTIVE: To establish whether muscle blood flow (MBF) measurements with O-water positron emission tomography could reliably identify patients with critical limb ischemia and detect and quantify a distal deficit in skeletal MBF in these cases. DESIGN: O-water positron emission tomography scans were performed at rest or during unloaded ankle plantar and dorsiflexion exercise of the diseased leg in 17 subjects with leg ischemia or on a randomly selected leg of 18 age-matched healthy control subjects. TcPO2 was evaluated with Novametrix monitors and perfusion of skin topically heated to 44 degrees C and adjacent nonheated areas with a Moor Instruments laser Doppler imaging scanner. RESULTS: The enhancement of MBF induced by exercise was significantly lower in ischemic than in normal legs, and the sensitivity and specificity of this phenomenon were similar to those of laser Doppler imaging or TcPO2 in identifying ischemia subjects. In addition, the exercise MBF deficit was predominant at the distal-leg levels, indicating the ability of the technique to help determine the correct level of amputation. CONCLUSIONS: Skeletal MBF of legs with severe ischemia can be detected accurately with O-water positron emission tomography and could add valuable information about viability of skeletal muscle in the residual limb when deciding the level of an amputation.

Effects of exercise training on calf tissue oxygenation in men with intermittent claudication.

OBJECTIVE: To determine the effects of exercise training on calf tissue oxygenation in men with peripheral arterial disease and intermittent calf claudication. DESIGN: This pilot study was prospective and longitudinal and used a one-group, pretest-posttest design. SETTING: Tertiary care medical center for veterans. PARTICIPANTS: Fifteen male veterans (mean age 69 years) with Fontaine stage IIa peripheral arterial disease and classic intermittent claudication. MAIN OUTCOME MEASUREMENTS: Before and after intervention, participants performed graded treadmill exercise tests while medial calf tissue oxygenation (StO(2), % oxyhemoglobin saturation) was monitored continuously with near-infrared spectroscopy. INTERVENTION: The intervention consisted of a 3-month exercise training program involving 3 sessions per week at the clinic (treadmill walking, calf ergometry) and 2 sessions per week at home (free walking, standing heel raises). RESULTS: After completion of the intervention, participants significantly increased their maximal treadmill exercise time from 7.19 to 11.27 minutes. Mean exercise StO(2) decreased from 29% to 19% saturation, StO(2) x time area increased from 421% * min to 730% * min StO(2) nadir, and StO(2) recovery time did not change significantly. CONCLUSIONS: After the exercise intervention, the improved treadmill walking performance was accompanied by greater calf tissue deoxygenation during exercise. Given the continued presence of ischemia, this finding may represent increased capillarization and diffusion-based enhancement of arteriovenous O(2) extraction.

Scanning laser-Doppler imaging of leg- and foot-skin perfusion in normal subjects: analysis of age, gender, site, and laser-type effects.

OBJECTIVES: To report normal values of skin perfusion in healthy subjects in three age groups using a laser Doppler imager; to determine differences attributable to gender, age, site, and use of red or near-infrared lasers; and to correlate transcutaneous oxygen with laser flux values. DESIGN: Flux and transcutaneous oxygen were measured at ten sites in the lower extremity in 60 subjects from three age groups. Heated and unheated sites were scanned with red and near-infrared lasers. RESULTS: Heat hyperemia was prominent at all sites. Small, statistically significant mean +/- SD differences were found between heated and nonheated sites for the red and near-infrared lasers (P = 0.02). All flux ratios were independent of gender but were higher in the oldest group. Plantar sites demonstrated higher flux in unheated areas and lower flux ratios compared with leg sites. Transcutaneous oxygen did not correlate significantly with flux for either laser type. CONCLUSIONS: Scanning laser-Doppler imaging flux values provide a reference for identifying patients at risk for tissue ischemia and poor healing potential caused by impaired circulatory reserve in the legs and distal feet. The lack of correlation between flux and transcutaneous oxygen in healthy individuals suggests that they measure different physiologic processes.

Cortical contusion induces trans-hemispheric reorganization of blood flow maps.

Cerebral blood flow (CBF), a surrogate of neural activity in the identification of brain regions involved in specific functions, has been used in this report to trace the compensatory enhancement of activity in non-traumatized areas of the brain following a focal lesion. We have previously shown activation of CBF in the cortex contralateral to a focal contusion, 24 h after the event. The present report extends the characterization of this trans-hemispheric cortical blood flow activation by studying its time course and regional distribution from 4 days to 4 weeks post-trauma. Adult male Sprague-Dawley rats received a cortical impact through a 6.3 mm craniotomy under halothane anesthesia. CBF was measured with the quantitative autoradiographic (14)C-Iodoantipyrine technique, in conscious animals, 4 days, 2 weeks and 4 weeks post-trauma. CBF was severely decreased at the site of impact where necrosis developed later, and it remained depressed in the surrounding areas throughout the observation period. Trans-hemispheric CBF enhancement was maximal at 4 days and it returned to control levels 28 days post-trauma. This phenomenon was present in all cortical regions symmetrical to the impact zone, but also in auditory, visual, entorhinal and insular cortex. These results suggest that the participation of the contralateral cortex in the recovery from unilateral brain trauma is not limited to the regions homologous to those that received the impact. The time course of CBF changes was found to be consistent with the recovery of motor function in this model.

Preamputation evaluation of limb perfusion with laser Doppler imaging and transcutaneous gases.

We studied 31 subjects with severe leg ischemia and 29 age-matched nonischemic control subjects to compare preamputation assessments of leg ischemia using laser Doppler imaging (LDI), transcutaneous partial pressure of oxygen (TcPO(2)), and transcutaneous partial pressure of carbon dioxide (TcPCO(2)). TcPO(2) and TcPCO(2) were evaluated with Novametrix Medical Systems, Inc, monitors (Wallingford, Connecticut) and perfusion (flux) of skin topically heated to 44 degrees C, and adjacent nonheated areas were evaluated with a Moor Laser Doppler Imager (Moor Instruments, Ltd; Devon, England). LDI flux of heated areas, its ratio to nonheated areas, and TcPO(2) (not TcPCO(2)) were lower in ischemic subjects than in control subjects. LDI flux ratio performed better than TcPO(2) in identifying ischemia, with fewer false positive and false negative results. Moreover, LDI flux of heated skin detected a proximal to a distal gradient of perfusion in ischemic subjects, while TcPO(2) did not. LDI was superior to TcPO(2) in discriminating correctly between ischemic and nonischemic skin. The results suggest that an LDI ratio below 5 indicates nonviable skin.

The mechanism of gentisic acid-induced relaxation of the guinea pig isolated trachea: the role of potassium channels and vasoactive intestinal peptide receptors.

We examined some of the mechanisms by which the aspirin metabolite and the naturally occurring metabolite gentisic acid induced relaxation of the guinea pig trachea in vitro. In preparations with or without epithelium and contracted by histamine, gentisic acid caused concentration-dependent and reproducible relaxation, with mean EC(50) values of 18 microM and E(max) of 100% (N = 10) or 20 microM and E(max) of 92% (N = 10), respectively. The relaxation caused by gentisic acid was of slow onset in comparison to that caused by norepinephrine, theophylline or vasoactive intestinal peptide (VIP). The relative rank order of potency was: salbutamol 7.9 > VIP 7.0 > gentisic acid 4.7 > theophylline 3.7. Gentisic acid-induced relaxation was markedly reduced (24 +/- 7.0, 43 +/- 3.9 and 78 +/- 5.6%) in preparations with elevated potassium concentration in the medium (20, 40 or 80 mM, respectively). Tetraethylammonium (100 microM), a nonselective blocker of the potassium channels, partially inhibited the relaxation response to gentisic acid, while 4-AP (10 microM), a blocker of the voltage potassium channel, inhibited gentisic acid-induced relaxation by 41 +/- 12%. Glibenclamide (1 or 3 microM), at a concentration which markedly inhibited the relaxation induced by the opener of ATP-sensitive K(+) channels, levcromakalim, had no effect on the relaxation induced by gentisic acid. Charybdotoxin (0.1 or 0.3 microM), a selective blocker of the large-conductance Ca(2+)-activated K(+) channels, caused rightward shifts (6- and 7-fold) of the gentisic acid concentration-relaxation curve. L-N(G)-nitroarginine (100 microM), a NO synthase inhibitor, had no effect on the relaxant effect of gentisic acid, and caused a slight displacement to the right in the relaxant effect of the gentisic acid curve at 300 microM, while methylene blue (10 or 30 microM) or ODQ (1 microM), the inhibitors of soluble guanylate cyclase, all failed to affect gentisic acid-induced relaxation. D-(P)-Cl-Phe(6),Leu(17)[VIP] (0.1 microM), a VIP receptor antagonist, significantly inhibited (37 +/- 7%) relaxation induced by gentisic acid, whereas CGRP (8-37) (0.1 microM), a CGRP antagonist, only slightly enhanced the action of gentisic acid. Taken together, these results provide functional evidence for the direct activation of voltage and large-conductance Ca(+2)-activated K(+) channels, or indirect modulation of potassium channels induced by VIP receptors and accounts for the predominant relaxation response caused by gentisic acid in the guinea pig trachea.

The mechanism of gentisic acid-induced relaxation of the guinea pig isolated trachea: the role of potassium channels and vasoactive intestinal peptide receptors

We examined some of the mechanisms by which the aspirin metabolite and the naturally occurring metabolite gentisic acid induced relaxation of the guinea pig trachea in vitro. In preparations with or without epithelium and contracted by histamine, gentisic acid caused concentration-dependent and reproducible relaxation, with mean EC50 values of 18 æM and Emax of 100 percent (N = 10) or 20 æM and Emax of 92 percent (N = 10), respectively. The relaxation caused by gentisic acid was of slow onset in comparison to that caused by norepinephrine, theophylline or vasoactive intestinal peptide (VIP). The relative rank order of potency was: salbutamol 7.9 > VIP 7.0 > gentisic acid 4.7 > theophylline 3.7. Gentisic acid-induced relaxation was markedly reduced (24 + or - 7.0, 43 + or - 3.9 and 78 + or - 5.6 percent) in preparations with elevated potassium concentration in the medium (20, 40 or 80 mM, respectively). Tetraethylammonium (100 æM), a nonselective blocker of the potassium channels, partially inhibited the relaxation response to gentisic acid, while 4-AP (10 æM), a blocker of the voltage potassium channel, inhibited gentisic acid-induced relaxation by 41 + or - 12 percent. Glibenclamide (1 or 3 æM), at a concentration which markedly inhibited the relaxation induced by the opener of ATP-sensitive K+ channels, levcromakalim, had no effect on the relaxation induced by gentisic acid. Charybdotoxin (0.1 or 0.3 æM), a selective blocker of the large-conductance Ca2+-activated K+ channels, caused rightward shifts (6- and 7-fold) of the gentisic acid concentration-relaxation curve. L-N G-nitroarginine (100 æM), a NO synthase inhibitor, had no effect on the relaxant effect of gentisic acid, and caused a slight displacement to the right in the relaxant effect of the gentisic acid curve at 300 æM, while methylene blue (10 or 30 æM) or ODQ (1 æM), the inhibitors of soluble guanylate cyclase, all failed to affect gentisic acid-induced relaxation. D-P-Cl-Phe6,Leu17[VIP] (0.1 æM), a VIP receptor antagonist, significantly inhibited (37 + or - 7 percent) relaxation induced by gentisic acid, whereas CGRP (8-37) (0.1 æM), a CGRP antagonist, only slightly enhanced the action of gentisic acid.

Peak and kinetic cardiorespiratory responses during arm and leg exercise in patients with spinal cord injury.

STUDY DESIGN: A paired comparison of the peak and submaximal responses of oxygen uptake and heart rate in patients with spinal cord injury (SCI) performing voluntary arm cycle exercise and functional electrical stimulation (FES) leg cycling exercise. OBJECTIVES: To test if the blunted heart rate response and slower rate of adjustment of oxygen uptake seen in patients with SCI performing FES leg cycle exercise are also characteristic of arm exercise in these patients. METHODS: Eight paraplegics performed incremental and constant work rate (CWR) exercise with the legs and arms. Mean response times (MRT) for Vo2 during exercise (on) and in recovery (off) were calculated from the breath-by-breath Vo2 profile. RESULTS: Peak heart rate was higher during incremental arm exercise, and uncorrelated with that observed during incremental FES leg cycling. For the same increase in Vo2, constant work rate arm exercise was associated with faster (and normal) Vo2 kinetics, greater increase in heart rate, and lower end-exercise blood lactate, compared to FES leg cycling. CONCLUSIONS: The consistently higher peak heart rate and Vo2, and faster Vo2 kinetics, for voluntary arm compared to FES leg cycle exercise suggest no intrinsic dysfunction of heart rate control in these paraplegics. Rather, these data suggest that during FES leg cycling the changes seen are due to some characteristic specific to the injury, such as reduced muscle mass and/or deconditioning of the remaining muscle. SPONSORSHIP: This research was supported by The Department of Veterans Affairs, Rehabilitation Research and Development Project #B603-RA. Spinal Cord (2000) 38, 340 - 345.

Increasing muscle mass in spinal cord injured persons with a functional electrical stimulation exercise program.

OBJECTIVE: To determine the magnitude of changes in muscle mass and lower extremity body composition that could be induced with a regular regimen of functional electrical stimulation (FES)-induced lower-extremity cycling, as well as the distribution of changes in muscle mass among the thigh muscles in persons with spinal cord injury (SCI). STUDY DESIGN: Thirteen men with neurologically complete motor sensory SCI underwent a 3-phase, FES-induced, ergometry exercise program: phase 1, quadriceps strengthening: phase 2, progressive sequential stimulation to achieve a rhythmic pedaling motion (surface electrodes placed over the quadriceps, hamstrings, and gluteal muscles); phase 3, FES-induced cycling for 30 minutes. Participants moved from one phase to the next when they met the objectives for the current phase. MEASURES: Computed tomography of legs to assess muscle cross-sectional area and proportion of muscle and adipose tissue. Scans were done at baseline (before subjects started the program), at first follow-up, typically after 65.4+/-5.6 (SD) weekly sessions, and at second follow-up, typically after 98.1+/-9.1 sessions. RESULTS: Increases in cross-sectional areas were found in the following muscles: rectus femoris (31%, p<.001). sartorius (22%, p<.025), adductor magnus-hamstrings (26%, p<.001), vastus lateralis (39%, p = .001), vastus medialis-intermedius (31%, p = .025). Cross-sectional area of adductor longus and gracilis muscles did not change. The ratio of muscle to adipose tissue increased significantly in thighs and calves. There was no correlation among the total number of exercise sessions and the magnitude of muscle hypertrophy. CONCLUSIONS: Muscle cross-sectional area and the muscle to adipose tissue ratio of the lower extremities increased during a regular regimen of 2.3 FES-induced lower extremity cycling sessions weekly. The distribution of changes was related to the proximity of muscles to the stimulating electrodes.

Knee kinetics during functional electrical stimulation induced cycling in subjects with spinal cord injury: a preliminary study.

The purpose of this preliminary study was to describe pedal effectiveness parameters and knee-joint reaction forces generated by subjects with chronic spinal cord injury (SCI) during functional electrical stimulation (FES)-induced bicycling. Three male subjects (age 33-36 years old), who were post-traumatic SCI (ASIA-modified level A, level T4-C5) and enrolled in an FES rehabilitation program, signed informed consent forms and participated in this study. Kinematic data and pedal forces during bicycling were collected and effective force, knee-joint reaction forces, knee generalized muscle moments, and knee-joint power and work were calculated. There were three critical findings of this study: 1) pedaling effectiveness was severely compromised in this subject population as indicated by a lack of overall positive crank work; 2) knee-joint kinetics were similar in magnitude to data reported for unimpaired individuals pedaling at higher rates and workloads, suggesting excessive knee-joint loading for subjects with SCI; and 3) shear reaction forces and muscle moments were opposite in direction to data reported for unimpaired individuals, revealing an energetically unfavorable knee stabilizing mechanism. The critical findings of this study suggest that knee-joint kinetics may be large enough to produce a fracture in the compromised lower limbs of individuals with SCI.

Anti-hyperalgesic effect of an ethanolic extract of propolis in mice and rats.

Propolis, or bee glue, which contains a complex mixture of secondary metabolites, has long been used in many countries for the management of several diseases. The purpose of this study was to evaluate, by means of several pharmacological models, the anti-hyperalgesic effect of propolis collected in the south of Brazil. The abdominal constrictions induced in mice by intraperitoneal injection of acetic acid (0.6%), kaolin (50 mg kg-1) or zymosan (40 mg kg-1) were inhibited to different extents by an extract of propolis (1-60 mg kg-1) administered intraperitoneally 30 min earlier; mean ID50 (concentrations resulting in 50% inhibition) values were 2.7, 10.8 and 10.7 mg kg-1, respectively, and maximum inhibition was 58 +/- 5, 57 +/- 10 and 51 +/- 5%, respectively. Given orally (25-200 mg kg-1, 1h previously) propolis also inhibited the abdominal constrictions induced by acetic acid (maximum inhibition 43 +/- 5%). When injected intraperitoneally (3-60 mg kg-1, 30 min previously), propolis attenuated both the neurogenic (first phase) and inflammatory (second phase) pain responses and paw oedema caused by intraplantar injection of formalin (2.5%); maximum inhibition was 32 +/- 5, 43 +/- 6 and 19 +/- 2%, respectively. Oral administration of propolis (25-200 mg kg-1, 1 h previously) inhibited both phases and reduced the oedema formation associated with the second phase of the formalin test (maximum inhibition 22 +/- 5, 33 +/- 6 and 26 +/- 3%) and extract of propolis (3-30 mg kg-1 i.p. or 25-100 mg kg-1 p.o., respectively 30 min and 1 h previously) significantly inhibited capsaicin-induced pain with maximum inhibition of 39 +/- 8 and 41 +/- 8%, respectively. When assessed in the Randall-Sellito test of pain, the extract of propolis (3-30 mg kg-1, i.p., 30 min previously) significantly reversed the hyperalgesia induced by intraplantar injection of bradykinin (3 nmol per paw) in rats (P < 0.01). In contrast with morphine the extract of propolis (< or = 100 mg kg-1, 30 min previously) was ineffective when assessed in the tail-flick and hot-plate thermal assays. Naloxone (5 mg kg-1 i.p.) reversed (P < 0.01) the effect of morphine (5 mg kg-1 s.c.) by 70 and 94% respectively in the first and second phases of the formalin test, but did not interfere with the analgesic effect of propolis (10 mg kg-1 i.p., 30 min previously). These results show that ethanolic extract of propolis, given systemically, has significant anti-hyperalgesic action when assessed in chemical, but not thermal, models of nociception in mice and rats. Its analgesic action seems to be unrelated to release or activation of the opioid system.

Functional electrical stimulation effect on skeletal muscle blood flow measured with H2(15)O positron emission tomography.

OBJECTIVE: To test the hypothesis that the limitation in muscle power development with functional electrical stimulation (FES) results from an insufficient increase in muscle blood flow (MBF) in response to activity. SUBJECTS AND METHODS: Five subjects with neurologically complete spinal cord injury (SCI) were tested to measure the MBF response to FES-induced knee extension. The MBF response to voluntary knee extension was measured in five age-matched, able-bodied controls. MBF was measured with positron emission tomography (PET) using H2(15)O as a tracer. Three scans were performed with muscle at rest (baseline), immediately after 16min of FES-induced or voluntary knee extension (activity), and 20min after the second scan (recovery). RESULTS: In SCI subjects, mean +/-SE MBF (mL/100g/min) values were: baseline = 1.85 +/- .48; post-FES = 31.9 +/- 5.65 (p = .0058 vs baseline); recovery = 6.06 +/- 1.52 (p = .0027 vs baseline). In able-bodied controls, mean +/-SE MBF values were: baseline = 8.52 +/- 3.24, post-voluntary exercise = 12.62 +/- 3.03 (p = .023 vs post-FES in SCI subjects); recovery = 10.7 +/- 6.01. CONCLUSIONS: MBF does not appear to be the limiting factor in muscle power generation with FES. The greater increase in MBF observed with FES in SCI subjects when compared with able-bodied subjects performing a similar task (unloaded knee extension against gravity) may relate to abnormal metabolism in FES-stimulated muscle.

Physiologic responses during functional electrical stimulation leg cycling and hybrid exercise in spinal cord injured subjects.

OBJECTIVES: (1) To determine if a hybrid exercise (leg plus arm) training program performed immediately after functional electrical stimulation (FES) leg cycle exercise (LCE) training would further improve aerobic capacity when compared with FES leg cycle training alone, and (2) to compare the submaximal responses occurring during both FES-LCE alone and hybrid exercise in the same SCI subjects. DESIGN: Nonrandomized control trial whereby subjects act as their own control. SETTING: Outpatient rehabilitation in a primary care hospital. PATIENTS: A volunteer sample (n = 11) of men 20 to 50 years old with complete spinal cord injury, free from cardiovascular and metabolic disease with spasticity. INTERVENTIONS: Three phases of exercise training: phase I, progressive FES-LCE to 30 minutes of exercise (n = 11); phase II, 35.2 +/- 16.2 sessions of FES-LCE (n = 11); phase III, 41.4 +/- 17.7 30-minute sessions of hybrid exercise (n = 8). MAIN OUTCOME MEASURES: (1) Aerobic capacity-a further increase after hybrid exercise when compared with FES-LCE alone; (2) submaximal physiologic parameters (oxygen uptake [VO2], heart rate [HR], blood lactate [BLa-])-measurement of these during constant work rate exercise and a training effect. RESULTS: VO2 (the body's ability to utilize oxygen) significantly improved (p < .05) after both FES-LCE and then further after hybrid training. Hybrid exercise training resulted in significantly (p < .05) greater work rates and VO2 values than both FES-LCE at baseline and training work rates. CONCLUSION: These subjects demonstrated that hybrid exercise performed twice a week provided sufficient intensity to improve aerobic capacity and provide a medium whereby patients with SCI can burn more calories than via FES-LCE alone. This has important implications for improving the health and fitness levels of individuals with SCI and may ultimately reduce their risk of cardiovascular disease.

Cholinesterase inhibition improves blood flow in the ischemic cerebral cortex.

The ability of central cholinesterase inhibition to improve cerebral blood flow in the ischemic brain was tested in Sprague-Dawley rats with tandem occlusion of left middle cerebral and common carotid arteries. Cerebral blood flow was measured with lodo- 14C-antipyrine autoradiography in 170 regions of cerebral cortex. The regional distribution of blood flow was characterized in normal animals by cerebral blood flow maxima in the temporal regions. After 2 h ischemia, minimum cerebral blood flow values were found in the lateral frontal and parietal areas on the left hemisphere, and a new maximum was found in the right hemisphere in an area approximately symmetrical to the ischemic focus. Heptyl-physostigmine (eptastigmine), a carbamate cholinesterase inhibitor with prolonged time of action improved cerebral blood flow in most regions, with the exception of the ischemic core. The drug also enhanced the ischemia-induced rostral shift of cerebral blood flow maxima in the right hemisphere. The effects of eptastigmine were more marked 24 h after ischemia. Discriminant analysis showed that data from only 22 regions was sufficient to achieve 100% accuracy in classifying all cases into the various experimental conditions. The redistribution of cerebral blood flow to the sensorimotor area of the right hemisphere of animals with cerebral ischemia, a phenomenon possibly related to recovery of function, was also enhanced by eptastigmine.