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Biomedical subjects

J R Steele

Publications and source records attributed to J R Steele.

12 recordsLinked to original sources
PubMed1995

Effect of work station design on sitting posture in young children.

The purpose of the study was to compare muscular activity levels and sitting posture displayed by 10 children (mean age = 4.7 years) when performing tracing tasks while seated at a traditional work station (level desk top, 5 degrees backward sloping seat) and at an ergonomically designed work station (15 degrees sloping desk top, 15 degrees forward sloping seat). EMG profiles of latissimus dorsi (LD), erector spine (ES), and superior trapezius (ST) were sampled using Medi-trace disposable surface electrodes for 10 min on the non-dominant side. Muscle activity was sampled (1000 Hz) every 2 min for 5000 ms while the subjects performed the tracing tasks at each station. Raw EMG signals of the five trials for each muscle were processed by removing signal offset, full-wave rectification, and integration. The subjects' posture was monitored from a lateral view using a Panasonic VHS video camera while the children were seated at each work station. Neck flexion angle and the angle between the torso and thigh (hip angle) were manually sampled from the video images each 1 min as an indication of the posture adopted by the subjects during the tracing tasks. Use of t-tests for dependent means indicated that there was no significant difference in either mean ES or ST muscle activity as a function of work station design. However, subjects demonstrated significantly less LD activity when seated at the ergonomic work station (mean = 20.9 V ms) compared with the traditional work station (mean = 24.4 V ms, t = -2.88, p = 0.018).(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMed1995

Traumatic anterior dislocation of the hip: spectrum of plain film and CT findings.

Traumatic anterior dislocation of the hip represents 11% of all hip dislocations and is classified into superior and inferior types [1]. Whereas inferior anterior hip dislocation is easily recognized on an anteroposterior radiograph of the pelvis, the radiographic appearance of superior anterior hip dislocation is less straightforward, often leading to an initial misdiagnosis of posterior hip dislocation. Misdiagnosis of the direction (anterior versus posterior) of a hip dislocation can result in failed closed reduction or an improper surgical approach to open reduction. In addition, recognition of associated impaction fractures is important, as patients with this finding have a greater tendency to develop traumatic arthritis [2, 3]. This pictorial essay, which is based on our experience with 20 cases of anterior hip dislocation, including five of the rare superior type, illustrates the spectrum of radiographic findings and distinguishing features associated with anterior hip dislocation.

Adult↗
PubMed1990

Biomechanical factors affecting performance in netball. Implications for improving performance and injury reduction.

Despite netball having one of the largest number of participants of any team game within the Commonwealth there has been limited research conducted which biomechanically analysed skills of the game. However, information presented from biomechanical analyses of skills can provide coaches with the necessary theoretical basis to teach netball fundamentals to junior players. Biomechanical information can also be used to refine the existing techniques of experienced netball players so they may achieve optimal technical performance of game skills while minimising the potential for injury. Changes to footwork rules and to the material properties of court surfaces and footwear could reduce stress placed on the musculoskeletal system. However, the factor which influences musculoskeletal stress to the greatest extent is a player's landing technique. Thus, the first concern for all netball coaches must be to teach all players to land correctly. The magnitude and rate of loading of the high vertical and horizontal ground reaction forces generated when players execute abrupt landings in netball are reduced more effectively by encouraging players to throw higher passes, requiring the receiver to jump upward to catch the ball. However, to maximise the reduction in stress placed on the musculoskeletal system on landing, players should be encouraged to land with the foot neutrally aligned (not abducted or adducted), ensure adequate hip and knee flexion, and reduce the foot-hip displacement by eliminating an exaggerated 'striding out' position often adopted by netball players. Apart from landing techniques, the only netball skill that has been objectively analysed is goal shooting. To improve shooting accuracy players should demonstrate greater flexion of the knees and shooting elbow when preparing to shoot, sufficient but not excessive hyperextension of the hand to stabilise the ball, minimisation of trunk, arm and forearm movements during the shooting action in favour of increased hand motion, greater release height and greater release velocity. If the potential for injury from poorly executed skills in netball is to be minimised, further research is required to identify the most efficient methods of performing all skills involved in the game, including pivoting, rebounding, defensive movement patterns, and attacking movement strategies.

Athletic Injuries↗
PubMed1981

Transient diffuse computed tomographic scan enhancement in multifocal seizures.

Previous reports have documented transient angiographic and nucleotide brain scan abnormalities in patients with focal seizures. We describe transient diffuse cortical computed tomographic scan enhancement in a 1-year-old infant with repetitive multifocal seizures. Similar scan abnormalities may be seen in certain asphyxiated infants and occasionally in victims of child abuse. The implications of these findings are discussed.

Electroencephalography↗
PubMed1981

Brainstem evaluation with CT cisternography.

Seventy-eight positive contrast computed tomography (CT) cisternograms were reviewed to assess the normal anatomy of the brainstem and its surrounding cisterns. Normal brainstem and cisternal anatomy was found to be constant and symmetrical. The review included six patients with brainstem gliomas and five patients with extraaxial masses. In these patients CT cisternography accurately identified mass formation and permitted the confident distinction of extraaxial from intra-axial masses. CT cisternography is a safe and accurate method for evaluating the anterior compartment of the posterior fossa. This procedure is particularly applicable to those cases where conventional CT yields insufficient diagnostic information.

Adolescent↗
PubMed1978

Computed tomography of the pancreas: the use of intravenous contast to define the dorsal surface of the pancreas.

After a non-selective review of 80 abdominal CT examinations, it was found that the use of intravenous contrast markedly improves the recognition of the superior mesenteric vein and the splenic vein. These veins lie adjacent to the posterior surface of the pancreas. When the pancreas is poorly seen due to inadequate retroperitoneal fat, when pancreatic size is borderline, or when pancreatic ductal obstruction is suspected on scans prior to intravenous contrast administration, the use of contrast may resolve the uncertainty.

Abdominal Neoplasms↗
PubMed1976

Extracorporeal magnet perivascular electromagnetic flow meters.

The "interrupted resonance" circuit proved effective in combination with an extracorporeal magnet in permitting electromagnetic blood flow measurements to be made in branch arteries of dogs by application of perivascular cuffs equipped with pick-up electrodes contacting the vessel wall. A four-turn coil, acting as a transformer secondary measures the amplitude of the magnetic field component which is effective in inducing the flow signal and thus permits calibrations for arbitrary orientations of the perivascular cuff relative to the magnetic field of the extracorporeal magnet. Recordings of mean and phasic blood flow in dogs' arteries provide illustrations of effectiveness in pharmacological studies and exhibit the reliability of the non-occlusive zero-flow base line obtained by de-energizing the magnet.

Animals↗
PubMed1974

A constant-field interrupted resonance system for percutaneous electromagnetic measurement of blood flow.

A combination of deformable flow probes of negligible lateral dimensions with an electronic circuit capable of providing a prolonged plateau of dB/dt = 0 and of sampling the flow signal at the end of this interval permits electromagnetic measurement of blood flow with a reliable zero base line secured by switching off the magnet. An extracorporeal magnet provides the magnetic field. The flow transducer is introduced into the vascular system percutaneously through a standard angiographic catheter by conventional technique. The idea of the current generator can be described as "principle of interrupted resonance." The current wave form can be described as a sequence of disconnected bisected sine waves joined at the apices by horizontal current plateaus where di/dt is strictly zero.

Animals↗