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Biomedical subjects

P G Harris

Publications and source records attributed to P G Harris.

At least 19 recordsLinked to original sources
PubMed2000

Frontal steady-state potential changes predict long-term recognition memory performance.

Converging evidence from event-related potential and functional brain imaging studies suggests that the brain activity at posterior regions of the frontal cortex can predict the strength of long-term memory traces. This study examined the relationship between posterior frontal steady-state visually evoked potential (SSVEP) latency changes and recognition memory after a delay of 7 days. Thirty-five female subjects viewed an 18-min television documentary program interspersed with 12 unfamiliar television advertisements while brain electrical activity was recorded from four pre-frontal, two posterior frontal and two occipital scalp sites. After 7 days, the recognition memory was tested for images coinciding with the 20 most prominent frontal SSVEP latency minima and maxima during the viewing of ten contiguous advertisements (advertisements 2-11). We found that images coinciding with posterior frontal latency minima were more likely to be recognized (58.7% recognition) than images coinciding with SSVEP latency maxima (45.3% recognition). Furthermore, the relationship between posterior frontal SSVEP latency and recognition performance after 7 days was only apparent at the left posterior frontal site. The correlation between the recognition performance and SSVEP latency evaluated at all eight sites reached significance only at the left posterior frontal site. These findings suggest that frontal SSVEP latency variations can be used to assess the strength of long-term memory encoding for naturalistic stimuli.

Adult↗
PubMed1999

A mechanical comparison of the immediate stability of three fixation devices used in wrist arthrodesis: a cadaveric study.

This study was designed to determine which of 3 fixation devices used in wrist arthrodesis provides the greatest immediate stability along 2 axes of movement. Twenty cadaver wrists were mechanically tested. Group 1 consisted of 7 wrists stabilized using a 2.3-mm Steinmann pin. Six wrists from the second group were immobilized with a 9-hole, 3.5-mm AO dynamic compression plate. The third group consisted of 7 wrists stabilized with an 8-hole, short-bend, precontoured low-contact dynamic compression plate. Stiffness and fracture force were determined in both forced flexion and forced pronation. The results showed that the Steinmann pin was the least stable of the 3 constructs in both axes of movement. No differences were observed between the 2 compression plates for either of the 2 axes of movement.

Arthrodesis↗
PubMed1997

Teaching of medical ethics: implications for an integrated curriculum.

This paper reports on an investigation into the teaching of medical ethics and related areas in the medical undergraduate course at the University of Queensland. The project was designed in the context of a major curriculum change to replace the current 6 year course by an integrated, problem-based, 4 year graduate medical course, which began in 1997. A survey of clinical students, observations of clinical teaching sessions, and interviews with clinical teachers were conducted. Data obtained have contributed to curriculum development and will provide a baseline for comparison and evaluation of the graduate course in this field. A view of integrated ethics teaching is advanced in the light of the data obtained.

Curriculum↗
PubMed1996

Carpal tunnel syndrome in the work place.

The management of patients with the CTS that appears to be related to occupational tasks is a complex issue. At this time, there is no definite evidence to show that any job is the sole cause of an individual worker's symptom complex. Management of patients in this situation requires surgical restraint coupled with an understanding of the worker's overall lifestyle. The most effective outcomes for all concerned appear to occur when there is cooperation among the patient, the physician, and the employer or his or her representatives. The recent prospective study by MacDougal that attempted to correlate job classifications with surgical outcome may be a very positive step in this direction.

Carpal Tunnel Syndrome↗
PubMed1994

Long-term follow-up of coverage of weight bearing surface of the foot with free muscular flap in a pediatric population.

Between 1985 and 1991, 13 muscular free flaps with split thickness skin grafts (10 latissimus dorsi, 2 rectus abdominis, and 1 gracilis) were done in 12 patients to cover the weight bearing surface of the foot. Four open wounds were closed primarily and nine unstable scars were replaced with a free flap. A retrospective analysis shows that over the short term the flaps provided a complete coverage of wounds, with a 100% survival of flaps, and permitted normal weight bearing ambulation starting at 1 month postoperatively. Long-term results show deep pressure sensation but no light touch sensation. All patients are able to wear normal shoes. Six patients (seven flaps) required further surgery to close subsequent wounds on the flaps: Three hypertrophic scars with recurrent ulcerations needed scar revisions, one child presented a fistula through the flap due to underlying osteomyelitis, and one patient presented a friction wound on the lateral malleolus requiring thinning of the flap. Two flaps presented an area of pressure necrosis through the full thickness of the flap and had to be replaced with another free flap (fasciocutaneous sensate flap) over the heel area. In conclusion, it seems that in the pediatric population, skin-grafted muscular coverage of the weight bearing surface of the foot is a good alternative, even if more problems with hypertrophic scarring around the grafts have been found than in the adult population. In two cases, the flaps had to be replaced because of pressure necrosis over the calcaneus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Porphyrin and chlorin distributions in a Late Pliocene lacustrine sediment.

The tetrapyrroles in a highly immature Late Pliocene lacustrine sediment (Willershausen, Germany) show a simple distribution of both chlorin and porphyrin components as the free bases. The major components are C32 desoxophylloerythroaetioporphyrin (DPEP), a C33 bicycloalkano porphyrin, the chlorin analogue of the latter, and desoxophylloerythrin and its chlorin counterpart. The structure of the novel bicycloalkano chlorin was determined using a combination of two-dimensional phase-sensitive COSY NMR and nOe studies. Measurements of delta 13C and other data indicate that DPEP and the bicycloalkano porphyrin were derived from the chlorophyll(s) of photosynthetic organisms utilising a common source of CO2, probably diatoms. The occurrence of DPEP and other minor alkyl porphyrins indicates that the chlorophyll defunctionalisation pathway leading to these components can occur at low temperature and was probably biologically mediated, as was the condensation leading to the fused ring components.

Aluminum Silicates↗
PubMed1983

The role of general practitioner research groups in the study of benzodiazepines.

The advantages of a once a day regime of a long half life benzodiazepine are illustrated by a general pratitioner study in the U.K., which showed that in a group of over 100 patients, clorazepate 15 mg nocte was equally as effective as diazepam 5 mg three times a day. Another study carried out on 50 patients randomly allocated to lorazepam 1 mg t.d.s. or to clorazepate, which was directly related to the low incidence of side effects and simplicity of dosage.

Adolescent↗
PubMed1981

Miscellaneous rheumatological conditions treated in monitored-release studies with feprazone.

In two monitored-release studies of feprazone (Methrazone), one in hospital and the other in general practice and involving a total of about 4,000 patients, there were 343 patients with a variety of sero-negative rheumatological conditions or soft tissue lesions. The diagnoses included spondylosis, ankylosing spondylitis, psoriatic arthritis, capsulitis, frozen shoulder, polymyalgia rheumatica and gout. Most of the patients were classified as moderately or severely affected. Feprazone in a dose of 200 mg thrice daily appeared to benefit about 60% of patients during a course of 8 weeks of therapy. No serious adverse reactions directly attributable to the drug were recorded. About 20% of patients stopped treatment because of side-effects, usually gastro-intestinal disturbance or rash. Two patients experienced a marked fall in platelet count which might have been due to the drug, but neither developed any signs of thrombocytopenic purpura.

Adult↗
PubMed1980

A monitored-release study of methrazone in general practice.

Methrazone, a non-steroidal anti-inflammatory drug, was used on a monitored release study in general practice to treat 2,693 patients with rheumatoid or osteoarthritis. In a dose of 200 mg three times daily, it appeared to produce clear benefit in between 50% and 60% of patients. Adverse reactions such as dyspepsia and skin rash led to the drug being withdrawn in 11% of patients. There were three major adverse reactions possibly due to the drug (haematemesis, rectal bleeding and acute purpura), but no cases of severe leucopenia or thrombocytopenia. Methrazone is a useful anti-inflammatory agent. In particular, it is unlikely to cause interactions with other drugs, including cardiac glycosides such as digoxin.

Adult↗