Specific immunotherapy with high dose SO standardized grass allergen tablets was safe and well tolerated.

BACKGROUND: Sublingual immunotherapy with grass allergen tablets may be the future treatment for grass pollen allergy because it reduces symptoms and medication use, improves quality of life and is easy to use. Rhinoconjunctivitis and asthma co-exist and we aimed to find a safe dose range of a self-administered grass allergen tablet (ALK Abello A/S) in patients suffering from rhinoconjunctivitis and asthma. METHODS: Four doses were investigated in a randomised, double-blind, placebo-controlled, dose escalation trial. Outside the pollen season 4 groups of 12 patients commenced treatment in a staggered manner, at intervals of 1 week. For 28 days doses of 75000 (approximately 15microg Phleum pratense protein 5), 150,000, 300,000, 500,000 standardised quality tablet (SQ-T) units or placebo were given once daily as sublingual tablets. RESULTS: Fourty three patients were randomised to receive either active treatment or placebo (3:1). Each dose group consisted of 12 patients except the 500000 SQ-T group (5 active, 2 placebo). No asthma exacerbations were seen and no serious or severe adverse events were reported. The majority of adverse events were local reactions. The number of adverse events was dose related. No patients withdrew from the study. CONCLUSIONS: Treatment with grass allergen tablets in doses up to 500000 SQ-T in patients with asthma and rhinoconjunctivitis was safe and well tolerated.

The effect of delayed-onset muscle soreness on stretch reflexes in human low back muscles.

The aim of the study was to investigate the effect of moderate delayed-onset muscle soreness (DOMS) on the short latency stretch reflex (SLR) and long latency stretch reflex (LLR) response i.e. electromyographic (EMG) onset latencies and EMG amplitudes in erector spinae (ES). Nine males with muscle soreness (DOMS group) were tested 24, 48 h, and 7 days post-exercise. Eight males (control group) were tested likewise. EMG was measured from ES bilaterally at the level of L3/L4. The SLR was elicited by mechanically tapping the ES at L3/L4, and the LLR was elicited by sudden loadings of the spine. Significant reductions in force during maximal voluntary contractions and range of motion, and a significant increase in muscle soreness (measured by pressure algometry) and subjective experience of soreness in the low back indicated DOMS 24, and 48 h post-exercise in the DOMS group. No changes were observed in the control group. The SLR and LLR response were unaffected by DOMS, i.e. no changes in EMG latencies and amplitudes were observed. In conclusion, despite changes in DOMS indicators, the reflex system protecting the stability of the lumbar spine is apparently capable of maintaining an appropriate triggering of SLR and LLR.

Adaptation to sudden unexpected loading of the low back--the effects of repeated trials.

The purpose of this study was to investigate short-term changes in reactions to sudden unexpected loading of the low back. The study utilized a set-up where a horizontal force of 58 N pointing forward suddenly was applied to the upper part of the subject's trunk. EMG activity from the erector spinae muscles and trunk movement data were recorded during 10 trials for 19 subjects. The analysis included EMG reaction time, mean rectified EMG amplitude during the period 50-250 ms after the sudden loading, and time elapsed until stopping of the forward movement of the trunk (stopping time). Reaction time means ranged from 66 to 97 ms (79+/-9 ms), and no difference was found between the trials. Conversely, the mean stopping time for the first trial (468 ms) was significantly higher than for trials 3-10 (359- 371 ms), and the average EMG amplitude during the period 50-250 ms after the sudden loading was lower for the first trial. This study showed that some subjects adapted to sudden unexpected loadings of the low back through a reduction in stopping time and a progression in EMG response during the first few trials. This possible adaptation to repeated trials have been overlooked in previous studies.

Movement of the upper body and muscle activity patterns following a rapidly applied load: the influence of pre-load alterations.

Sudden loading of the spine is not only considered a risk factor for the development of low-back pain but also enables an evaluation of the stability of the spine when conducted under laboratory conditions. In the present study the upper spine was pulled in the anterior direction and the stiffness as well as activity in the erector spinae muscle was measured with different pre-tension in the erector spinae. The results showed that increased activity in the erector spinae prior to loading led to increased stiffness (stiffness coefficients from 297 Nm rad(-1) to 438 Nm rad(-1)) and a decrease in the extra neural signal input to the muscles to maintain the stability. It is therefore clear that increased tension in the erector spinae muscle will create a larger stability of the spine to anterior perturbations. However, contracting the muscles around the spine increases the load on the spinal structures. In 34% of the experiments a silent period in the electromyographic signal was present after loading in the period when the torso was moving in the anterior direction. This phenomenon is discussed.

Biomechanical analysis of the effect of changing patient-handling technique.

The objective of the study was to assess the changes in the mechanical load on the low-back when shifting from a self-chosen to a recommended patient-handling technique. Nine female health care workers without formal education in patient-handling carried out 8 different tasks involving moving, turning and lifting situations. By means of a dynamic 3D biomechanical model of the lower part of the body, peak torque, compression and shear forces at the L4/L5 joint were compared using the two different patient-handling techniques. In 5 of the 8 tasks, a significant reduction was observed in spinal loading. Application of the recommended technique decreased the compression value significantly for all tasks with a mean value above 3000 N. For the two tasks with the highest compression values when using the self-chosen technique (4223, 4446 N), the loading was reduced with 36% and 25%, respectively. If the principles behind the recommended technique are implemented and maintained, a decrease in the risk of low-back disorders during patient-handling should thus be expected.

A dynamic 3D biomechanical evaluation of the load on the low back during different patient-handling tasks.

The objective of this study was to investigate the low-back loading during common patient-handling tasks. Ten female health care workers without formal training in patient handling performed nine patient-handling tasks including turning, lifting and repositioning a male stroke patient. The low-back loading was quantified by net moment, compression, and shear forces at the L4/L5 joint, measured muscle activity (EMG) in erector spinae muscles and rate of perceived exertion (RPE; Borg scale). The experiments were videotaped with a 50Hz video system using five cameras, and the ground and bedside reaction forces of the health care worker were recorded by means of force platforms and force transducers on the bed. The biomechanical load was calculated using a dynamic 3D seven-segment model of the lower part of the body, and the forces at the L4/L5 joint were estimated by a 14 muscles cross-sectional model of the low back (optimisation procedure). Compression force and torque showed high task dependency whereas the EMG data and the RPE values were more dependent on the subject. The peak compression during two tasks involving lifting the patient (4132/4433N) was significantly higher than all other tasks. Four tasks involving repositioning the patient in the bed (3179/3091/2932/3094N) did not differ, but showed higher peak compression than two tasks turning the patient in the bed (1618/2197N). Thus, in this study the patient-handling tasks could be classified into three groups-characterised by lifting, repositioning or turning-with different levels of peak net torque and compression at the L4/L5 joint.

Increase in spinal stability obtained at levels of intra-abdominal pressure and back muscle activity realistic to work situations.

In this study, sudden load was applied to the trunk and situations with alternating low levels of intra-abdominal pressure (IAP) realistic to work situations were compared. The aim was to see if IAP and the small increases in co-contraction of back muscles that follow are capable of increasing the stiffness of the lumbar spine. Nine subjects participated in ten sudden load situations during which they were asked to hold a box and conduct a percentage of maximal IAP. The hip was fixed and the load was applied horizontally on the trunk. EMG, IAP, and movement of the trunk were measured. It was found that IAP of a size likely to appear in work situations, and the concomitant increase in muscle co-activation increased the spine stiffness. This increase in stiffness decreased the movement caused by the sudden load. These results show that both abdominal- and back muscles may have an important role in stabilising the spine, and in decreasing movements caused by sudden loads likely to appear in numerous work

Intra-abdominal pressure increases during exhausting back extension in humans.

The aim of this study was to investigate in humans the effect of maintained spinal load on the intra-abdominal pressure (IAP), low back kinematics and trunk muscle activity. This study consisted of two endurance tests for the low back muscles performed 3 weeks apart. Nine healthy subjects participated in the study. In the first test (upright-test), the subject had to pull with the back muscles at a constant force in an upright position, and in the second test (incline-test), the subject had to resist a constant forward pulling force while standing with a 45 degrees inclination of the back in relation to vertical. The IAP, rate of perceived exertion and electromyogram (EMG) from the erector spinae, iliocostalis lumborum, rectus abdominus and the external and internal oblique muscles were measured using surface electrodes. There was no significant difference in endurance time between the two tests. Both tests showed a significant increase in EMG amplitude with time for all muscles except the erector spinae muscle. A decrease in the median frequency for the erector spinae muscle was found indicating fatigue, and since no increase in EMG amplitude was found a decrease in force output from the muscle must be assumed. The IAP increased significantly during both tests. There was a considerable variation between the subjects in the size of this development, but the pattern was the same for all subjects. In conclusion it was found that trunk extension until exhaustion initiates an increase in the activity of the abdominal muscles and an increase in the IAP as the low back muscles become fatigued.