Analysis of postural stability following posterior spinal fusion in adolescents with idiopathic scoliosis.

This study uses experimental data acquired from adolescents with idiopathic scoliosis to assess their postural control during quiet standing before and after posterior spinal fusion. Statistically significant differences were seen when comparing the pre- and post-surgical measures of balance calculated from data for three different test conditions.

Using a bi-planar postural stability model to assess children with scoliosis.

This study examines the postural stability of children with idiopathic scoliosis, using experimental data and a model of sway that includes mediolateral (ML) and anterioposterial (AP) components. The experimental data includes center of pressure (COP) measurements calculated from data acquired using two Advanced Medical Technology, Inc. (AMTI) force plates. Sway metrics are computed and compared with the model simulation, which successfully reproduced the clinical data from 16 children with scoliosis and 20 typically-developing children. This study is part of the first phase of a multi-year study designed to systematically assess whether fusing the spine to L4 in children with scoliosis has a significant impact on physical function and quality of life.

Application of a bi-planar postural stability model in children with cerebral palsy.

This study presents initial results from a bi-planar model used to investigate the neurological factors affecting balance deficits in children with diplegic cerebral palsy (CP). The model uses an inverted pendulum to describe sway in both the anteroposterior (AP) and mediolateral (ML) planes. The study presents Center of Pressure (COP) data from 17 children diagnosed with spastic diplegic CP using two standard AMTI force plates. Sway metrics in the time and frequency domains in the AP and ML planes were calculated and compared to simulations produced by the model. The proposed bi-planar model successfully reproduced sway signals acquired from experimental (clinical) data.

Biomechanical implications of the negative heel rocker sole shoe: gait kinematics and kinetics.

Rocker sole shoes are commonly prescribed to diabetic patients with insensate feet. Recent passage of the therapeutic shoe bill has drawn an increased focus to prescription rehabilitative footwear. The purpose of this work is to investigate the dynamics of lower extremity joints (hip, knee and ankle) with the application of a negative heel rocker sole shoe under controlled lab conditions. Forty normal adults volunteered for gait evaluations using controlled baseline and prescription negative heel rocker sole shoes. Three-dimensional motion analysis techniques were used to acquire kinematic and kinetic data using a six-camera Vicon 370 motion system and two AMTI force plates. No significant change in walking speed or stride length was seen with the negative heel rocker shoe, although cadence was increased. The most significant kinematic changes with the application of the negative heel shoe occurred at the ankle in the sagittal plane with increased plantarflexion at terminal stance. Significant hip and knee changes were also noted with increased mid-stance hip extension and knee flexion. The most significant kinetic effects were seen in the transverse plane followed by changes in the sagittal and coronal planes. Changes in power were mostly noted in the sagittal plane. Other statistically significant changes in gait kinematics and kinetics were observed, although the magnitudes and durations were limited and as a result were not considered clinically significant. The study results indicated the negative heel rocker shoe significantly altered proximal joint metrics (hip and knee). The most significant distal joint alterations were seen in sagittal plane ankle kinetics. These kinematic and kinetic changes, along with previously studied effects of pressure relief at the metatarsal heads, should aid medical professionals in prescribing prophylactic footwear.

Combined sagittal and coronal plane postural stability model.

We present a preliminary study of combined anterior posterior (AP) and medial lateral (ML) sway assuming a classic inverted pendulum with included subtalar movement. Based on a feedback control posture model in the sagittal plane as presented by Maurer and Peterka, we have investigated parameters needed to model ML sway components. Center of pressure (COP) data was collected from a population of 8 normal adults (age 18 to 30 years) using a dual AMTI force plate system. Fourteen different sway metrics were calculated. The collected data was successfully compared to numerous simulations of the model where model parameters were varied and the goal was to reproduce both AP and ML components.

Biomechanics of cranial dynamics during daily living activities.

Motion tracking capabilities of a head-mounted accelerometer apparatus were investigated in conjunction with three-dimensional motion analysis techniques during activities of daily living. In this report, measures between systems are compared for jogging, toe-touching, and start-from-rest tasks. Good fidelity was found for most measures between systems; some phase shifts and amplitude discrepancies were observed, and attributed to transducer orientation and system asynchrony. This preliminary work demonstrates the potential benefits of hybrid motion analysis systems.

Biomechanics of the double rocker sole shoe: gait kinematics and kinetics.

This paper reports the kinematic and kinetic changes in gait with bilateral double rocker sole shoe modifications. Three-dimensional motion analysis techniques were used to evaluate gait characteristics (temporal-spatial, kinematic, and kinetic measures) of forty (40) subjects while wearing baseline and double rocker sole shoes. Walking speed was unchanged by the double rocker modification. Sagittal plane motions showed significant change at the pelvis, hip, knee, and ankle. (p = 0.01). The toe-only rocker consistently resulted in increase in posterior pelvic tilt (p =0.01). Kinetic changes were observed at the hip in the sagittal and transverse planes, and at the knee and ankle in the sagittal planes. Changes in pelvic tilt and hip rotation were hypothesized to result from feelings of imbalance during ambulation with the double rocker sole shoe.

Planning nursing education for the 21st century.

In looking towards the 21st century, the faculty at the Presbyterian Hospital School of Nursing, along with the Presbyterian Health Services Corporation and Queen's College, adopted a 1-2-1 programme. The process of developing a new nursing curriculum is presented as the task force proceeded from the philosophy and goals to conceptual framework and curriculum objectives. After discussions with nurse administrators and educators, extensive literature reviews and brainstorming sessions, concepts and subconcepts were chosen to form a philosophy. The metaparadigm of nursing and other related concepts were then organized into a conceptual framework. Ongoing communication and feedback from the faculty ensured group ownership of all documents. The eclectic organizational scheme was a good fit for a large faculty with differing beliefs and values about a nursing curriculum. The process of developing a future orientated nursing curriculum has been exciting, challenging and rewarding. The faculty is committed to the new philosophy, goals and conceptual framework and believe that the 1-2-1 programme will educate future practitioners who are prepared to meet the challenges and changes in health care for the 21st century.

The mu opiate receptor is responsible for descending pain inhibition originating in the periaqueductal gray region of the rat brain.

Opiate agonists exhibiting selectivity for mu, kappa, sigma, and delta opiate receptors were microinjected into the periaqueductal gray region (PAG) of the brain of rats to determine the receptor subtype(s) associated with the initiation of descending pain inhibition. The spinally organized, heat nociceptive tail-flick reflex was used to detect analgesia. Only morphine (mu) and [D-Ala2,D-Leu5]enkephalin (DADLE) (delta greater than mu) produced analgesia. However, both drugs appeared to be acting through the mu (morphine) receptor, since: (1) the action of DADLE was not inhibited by delta receptor antagonists, (2) a more highly selective delta agonist [D-Pen2,D-Pen5]enkephalin was ineffective and (3) agonists selective at other non-mu receptor sites (ethylketocyclazocine and U50,488H for kappa; n-allylnormetazocine for sigma) were also ineffective. It appeared that DADLE might be acting as a partial agonist at the morphine receptor in the PAG. The peptide was an agonist with low efficacy, and when a maximally effective dose of the peptide was administered simultaneously with morphine antagonism was observed. Ethylketocyclazocine and n-allylnormetazocine were also found to antagonize morphine, an observation that is consistent with the suggestion that they may act as mu receptor antagonists in addition to their agonistic action at kappa and sigma receptors, respectively. Thus, mu receptors appear to be responsible for the spinopetal analgesia from the PAG of the rat.

Normal resting and exercising muscle blood flow during acute ethanol infusion.

We have examined the effect of ethanol on muscle blood flow at rest and during electrically stimulated exercise in five normal dogs using the isolated gracilis muscle preparation. Under pentobarbital anesthesia and mechanical ventilation, ethanol (15% in 0.9% NaCl) infused at 4 mL/min for 2 hr produced an arterial blood concentration of 268 +/- 10 mg/dL (X +/- SEM). Resting muscle blood flow was 6.3 +/- 0.9 mL/min/100 gm in 8 dogs infused with saline alone. During stimulated contraction using supramaximal voltage at a rate of 5 stimuli/sec, respective mean flows for ETOH and saline dogs at 1, 5, 10, and 30 min were 35.5, 19.9, 27.7, 22.2, and 22.0, 20.0, 23.6, and 19.1 mL/min/100 gm. The 1-min flow rate for ethanol infused animals was significantly greater (P < 0.05) than that observed in saline infused animals. The remainder of the values were not significantly different. Potassium release from contracting muscle was normal. These observations do not support the theory that ethanol induces vasoconstriction in the vascular bed of skeletal muscle nor do they support the postulation that muscle cell ischemia plays a role in alcoholic myopathy.