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Biomedical subjects

G Self

Publications and source records attributed to G Self.

9 recordsLinked to original sources
PubMed2000

Memory conformity: exploring misinformation effects when presented by another person.

Two experiments demonstrate that post-event information, when delivered by another person, can affect people's memory reports. In the first experiment participants were shown several cars, and later, in pairs, given an 'old'/'new' recognition test on these cars plus several lures. There was a small but reliable effect of memory conformity. When the person was given misinformation this lowered accuracy, while presenting accurate information increased accuracy. In the second experiment participants, in pairs, viewed an identical crime except that half saw an accomplice with the thief and half did not. Initial memories were very accurate, but after discussing the crime with the other person in the pair (who saw a slightly different sequence), most pairs conformed. Confidence ratings strongly predicted which person in the pair persuaded the other. Parallels with eyewitness testimony in the Oklahoma bombing case and implications for police interviewing more generally are discussed.

Adult↗
PubMed1999

Vascular surgical society of great britain and ireland: audit of surgical technique during carotid endarterectomy by intraoperative duplex ultrasonography: trainees compared with consultant

BACKGROUND: There has been increasing interest in audit of outcome following surgery. A previous study reported a significant difference in clinical outcome between consultant and trainees but there is no information on technical factors. Duplex ultrasonography before wound closure was used to compare clinical and technical outcome for consultant and trainees. METHODS: Patients underwent endarterectomy (89 by consultant, 60 by six trainees). In the consultant group nine vessels were patched and 36 patients underwent shunting compared with seven and 31 respectively for trainees. RESULTS: In the consultant group there were two deaths, one stroke, one transient ischaemic attack (TIA) and two cranial nerve injuries. The neurological event rate was 2 per cent, and overall stroke and death rate 3 per cent. There were ten residual flaps (11 per cent) (three re-explored) and eight kinks (9 per cent). The residual stenosis rate was 10 per cent (nine of 89) and following re-exploration this reduced to 7 per cent. In the trainee group there was one death, two strokes, one TIA and one cranial nerve injury. The neurological event rate was 5 per cent, and the overall stroke and death rate 3 per cent. There were nine flaps (15 per cent) (four re-explored) and 13 kinks (22 per cent). The residual stenosis rate was 22 per cent (13 of 60) which reduced to 15 per cent (nine of 60) following re-exploration. There was no significant difference in clinical outcome between consultant and trainees but there was an increased incidence of technical problems among the trainees (t = 2.12, P < 0.05). CONCLUSION: Intraoperative duplex ultrasonography is a valuable method for assessing surgical technique; it gives immediate feedback to the surgeon, enables corrective measures to be taken and may facilitate training.

Journal Article↗
PubMed1996

Comparison of UW solution and St. Thomas' solution in the rat: importance of potassium concentration.

BACKGROUND: University of Wisconsin solution (UW) is in limited clinical use for heart transplantation, but there are doubts about its efficacy and concerns about the effect of its high K+ concentration on endothelium. St. Thomas' solution with or without aspartate is widely used and is of proven efficacy. METHODS: Using a modified (starch-free) variant of UW (MUW) we studied: (1) recovery of function with UW compared with aspartate-containing St. Thomas' solution; (2) effect of elevation of K+ in St. Thomas' solution to the level in UW; and (3) effect of reduction of K+ in UW and addition of Ca2+ or aspartate. Isolated rat hearts underwent 7 hours of arrest at 1 degrees C using MUW with or without 20 mmol/L aspartate or using aspartate-containing St. Thomas' solution. RESULTS: Functional recovery with MUW (51.8% +/- 2.5%) was superior to that with aspartate-containing St. Thomas' solution (37.1% +/- 4.3%; p < 0.01). Addition of aspartate to MUW had no effect. During 6 hours of arrest, lowering the K+ in MUW from 125 mmol/L to 20 mmol/L reduced functional recovery from 59.9% +/- 4.2% to 42.3% +/- 4.3% (p < 0.01). The addition of 1 mmol/L Ca2+ had no effect. Elevation of K+ in St. Thomas' solution produced more rapid arrest but no improvement in recovery. CONCLUSIONS: The protective effect of starch-free UW is greater (+13%) than that of aspartate-enriched St. Thomas' solution. Reduction of K+ in UW to lessen possible deleterious effects would decrease its protective effect by about 30% to a level comparable with that of St. Thomas' solution.

Animals↗
PubMed1993

Exogenously administered alpha-bungarotoxin binds to embryonic chick spinal cord: implications for the toxin-induced arrest of naturally occurring motoneuron death.

Administration of alpha-bungarotoxin and other curare-like drugs during embryogenesis arrests motoneuron death which normally occurs in the spinal cord from day 6 to day 10 of embryogenesis. The accepted explanation is that such motoneuron rescue is mediated by inhibition of neuromuscular transmission following the blockade of nicotinic cholinoceptors at the neuromuscular junction. In this study we investigated a further possibility, namely that motoneuron rescue might also involve the blockade of alpha-bungarotoxin-sensitive sites within the spinal cord. The kinetic profile of [125I]alpha-bungarotoxin binding was examined in the brachial and lumbar regions of chick spinal cord at embryonic day 15. Binding was specific and apparently saturable within the range 1-34 nM reaching a maximum after 45 min. Specific binding involved a single class of non-interacting sites with a KD of 8.0 nM and a Bmax of 106 +/- 12 fmol/mg of protein. Nicotine displaced specific [125I]alpha-bungarotoxin binding in a concentration-dependent manner. Furthermore, specific binding dissociated slowly in the absence of nicotine. Autoradiographs localizing [125I]alpha-bungarotoxin binding in embryonic spinal cord revealed that, at embryonic day 15, specific toxin binding sites could be detected throughout the gray matter. In contrast, at embryonic day 6, the ventral horn contained the majority of specific binding sites. Exogenously administered [125I]alpha-bungarotoxin reached and bound to nicotine-sensitive sites in the spinal cord at embryonic day 7. To conclude, these data demonstrate that central nicotine-sensitive sites which bind [125I]alpha-bungarotoxin in a saturable and specific manner were present at the beginning of the critical motoneuron death phase of neurogenesis and that they were accessible to exogenously administered toxin. It is proposed that the [125I]alpha-bungarotoxin binding characterized here is to a class of putative alpha-bungarotoxin-sensitive nicotinic cholinoceptors. These studies raise the possibility that alpha-bungarotoxin blockade of such putative nicotinic cholinoceptors within the spinal cord may contribute to toxin-induced arrest of naturally occurring motoneuron death.

Animals↗
PubMed1986

Comparison of the protective effects of N-acetylcysteine, 2-mercaptopropionylglycine and dithiothreitol against acetaminophen toxicity in mouse hepatocytes.

The effects of N-acetylcysteine (NAC), 2-mercaptopropionylglycine (MPG) and dithiothreitol (DTT) on the metabolism and toxicity of acetaminophen (APAP) were examined in isolated mouse hepatocytes maintained in primary culture on collagen-coated dishes. Both NAC and MPG increased the formation of the glutathione and sulfate conjugates of APAP and decreased the covalent binding of the APAP reactive metabolite to cellular protein. DTT did not increase APAP metabolism but did decrease covalent binding. NAC, MPG and DTT decreased plasma membrane damage, as measured by leakage of lactate dehydrogenase from hepatocytes, during a 4-h incubation in 5.0 mM APAP. NAC, MPG and DTT also reduced the APAP-induced fall in glutathione levels in these cells. In other experiments, hepatocytes were exposed to 5.0 mM APAP for 1 h and then incubated during a post-exposure period in APAP-free medium. Damage increased during this post-exposure incubation. Addition of DTT, but not NAC or MPG, after APAP exposure protected the hepatocytes from plasma membrane damage during the post-exposure period. These results indicate that NAC and MPG exert their protective effects by their action on the reactive metabolite of APAP. As well as its effect in reducing the formation of the reactive metabolite, DTT has a potent protective effect against the toxic processes initiated by the APAP reactive metabolite.

Acetaminophen↗