Subjective organization and the visibility of illusory contours

The effects of the differential organization of a Necker cube on the perceived salience of an embedded illusory triangle were examined. Overall figural salience was greater when the triangle appeared to be localized on the front rather than the back cube face. Illusory contour salience also increased with increasing inducing area contrast and was greater when the figure was oriented on cardinal as compared to oblique coordinates. However, the latter effects were independent of perceived location within the cube. The finding that subjective organizational and structural factors influenced the perceived salience of the illusory figure but did not interact is consistent with van Tuijl and Leeuwenberg's (1982) suggestion that top-down and bottom-up determinants can operate independently in illusory contour perception.

The effects of signal salience and caffeine on performance, workload, and stress in an abbreviated vigilance task

In 2 experiments, a 12-min computerized vigilance task was demonstrated to reproduce the vigilance decrement, high workload (NASA-TLX), and stressful character (Dundee Stress State Questionnaire) of vigilance tasks lasting 30 min or more. In Experiment 1, the abbreviated task was also shown to duplicate the signal salience effect, a major finding associated with long-duration vigilance tasks. Moreover, Experiment 2 showed that performance on the abbreviated task can be enhanced by caffeine - a drug that benefits long-duration tasks. This enhancement effect was limited to performance, however, suggesting that caffeine influences factors that control signal detection but not those that control task-induced stress. The results parallel those obtained with long-duration tasks and support a resource-depletion model of the vigilance decrement. The abbreviated task might be useful in situations in which long-duration tasks are precluded (e.g., performance assessment batteries, neuropsychological testing, and brain imaging).

The impact of structured training on academic medicine in the UK

Introduction of structured training has been a recent event. The programmes have been modelled on curricula produced by the medical royal colleges. Regular assessment throughout the training has helped to achieve the designed goals. This reform encourages research for up to 1 year. However, the research year would not be funded by the normal National Health Service channels. The period of research can be extended by a year without losing the national training number. If the specialist registrars take this towards the end of year 4 then they can continue in research and acquire the certificate of 'Completion of Specialist Training' yet continue with the research for a degree by thesis. Clinical competence needs new ways of measurement without adhering to time periods of training. This will enable clinicians not to turn away from academic medicine because of longer periods of training needed prior to being appointed to a substantive academic post, compared with a colleague who is pursuing a clinical career.

Reforming higher specialist training in the United Kingdom--a step along the continuum of medical education

OBJECTIVES

The requirement to align the arrangements for postgraduate training in the United Kingdom with those elsewhere in the European Community provided the opportunity to review and reform our arrangements for higher specialist training. This paper describes the case for change--the strengths and deficiencies of the traditional pattern of postgraduate medical training, demographic influences in the medical workforce and the need for a more structural or planned approach to training.

CONCLUSIONS

Over the past 5 years substantial progress has been made: the introduction of new regulatory arrangements and a new higher specialist training grade; the development of a managed and flexible system for delivering training to standards set by the Royal Colleges and which can accommodate the needs of those pursuing academic and research medicine; and the opportunity for trainees' progress to be measured against published curricula. The significant programme of change has been underpinned by careful workforce planning and the publication of comprehensive guidance. Significant reform of higher specialist training has been achieved. This paper also makes the case for a more strategic approach to planning and developing medical education across the continuum, from entry to medical school until retirement, which can guide medical education and improve patient care into the next millennium.

Effects of monoamine oxidase inhibitors and dopamine agonists on the behavior of mammal- and frog-eating snakes

Skin mucus of the frog, Xenopus laevis, induces climbing and attenuates tongue flicking in Nerodia sipedon; these effects are induced alone and are potentiated by L-deprenyl, a monoamine oxidase type B inhibitor (MAO-Bi), but not by clorgyline, an MAO type A inhibitor (MAO-Ai). Both MAO-A and MAO-B metabolize dopamine, with MAO-B having the higher affinity; MAO-A selectively metabolizes serotonin and norepinephrine and MAO-B is selective for phenylethylamine. It was hypothesized that clorgyline and L-deprenyl would differentially modulate tongue flicking and climbing in frog-eating (Nerodia erythrogaster) and mammaphagous (Elaphe o. obsoleta) snakes, based on physiological differences between the species. L-Deprenyl caused a decrease in tongue flicking and climbing by Elaphe and an increase in climbing by Nerodia, whereas clorgyline did not alter tongue flicking, climbing, or locomotor activity in either species. To further assess the role of dopamine, hybrid black/gray rat snakes, E. o. spiloides, were administered the D1 and D2 dopamine receptor agonists SKF 77434 (SKF 38393, N-allyl) and quinpirole, respectively. SKF 77434 and quinpirole attenuated climbing, but only SKF 77434 attenuated tongue flicking in Experiment 3; neither drug affected locomotor activity. Results suggest that dopaminergic stimulation by MAO-Bi and dopamine agonists modulates tongue flicking and climbing behaviors in snakes, and that the contrasting climbing reactions induced by MAO-Bi between Elaphe and Nerodia may be linked to quantitative differences in endogenous catecholamine levels and/or to the numbers and sensitivity of receptors.

Research in higher surgical training--the West Midlands view

A questionnaire on the role of research in higher surgical training was posted to all in-post NHS Consultants (n = 96) and Higher Surgical Trainees (n = 42) in the West Midlands Region. Replies were received from 80 consultants (83 per cent) and 37 trainees (88 per cent). Over 95 per cent of responders had undertaken some research activity previously. The vast majority of consultants (90 per cent) and trainees (95 per cent) thought that their research period had been beneficial; most would undertake research again even if not essential for higher surgical training (consultants 80 per cent, trainees 70 per cent). Research was felt to be essential for all trainees by 50 per cent of respondents in both groups; 78 per cent of consultants and 86 per cent of trainees also thought that all potential academics should obtain a degree by thesis. Most of the study participants thought that the appropriate time for research activity was as a post-FRCS registrar (consultants 72 per cent, trainees 80 per cent); 80 per cent of consultants and 67 per cent of trainees felt that this research period should be funded by the NHS. A planned, supervised and funded one-year period of research was favoured by the majority of consultants (54 per cent) and trainees (73 per cent) for non-academic general surgical trainees in the future.

The Angelchik prosthesis behaves as a fundoplication

It is not known why the Angelchik prosthesis prevents gastro-oesophageal reflux. A review of 53 barium meal examinations in 39 patients with the prosthesis showed that in 43 examinations the prosthesis was below the diaphragm. In 38 of these a small knuckle of stomach had herniated through the prosthetic ring alongside the oesophagus, forming a small intra-abdominal para-oesophageal hernia. Radiological reflux occurred in only one patient with such a hernia. In the remaining five examinations where the prosthesis was correctly situated in the abdomen, there was no hernia within the prosthetic ring and reflux occurred in three. In ten examinations the prosthesis had migrated into the mediastinum. None of these showed a hernia and reflux occurred in eight. It is suggested that the Angelchik prosthesis results in the formation of a small para-oesophageal hernia within a loosely fitting ring within the abdomen and this is a requirement for the success of the Angelchik prosthesis. Radiographically the intra-abdominal para-oesophageal hernia inside the prosthesis results in buttressing of the intra-abdominal oesophagus in a manner similar to a fundoplication.

Paraoesophageal hiatus hernia: surgery for all ages

The results of surgery for paraoesophageal hiatus hernia over a 10-year period have been studied. From a group of 26 symptomatic patients, elective repair has been undertaken in 20 (mean age of 65.6 years) and emergency repair in four (mean age of 73.1 years). Emergency surgery was associated with a fivefold increase in mortality, and anatomical repair gave a satisfactory result in 90% (CI 77-100) of survivors. Surgical treatment should be considered for all symptomatic patients with paraoesophageal hiatus hernia.

Prospective randomized trial of Nissen fundoplication and Angelchik prosthesis in the surgical treatment of medically refractory gastro-oesophageal reflux disease

Fifty patients with gastro-oesophageal reflux disease refractory to multiple courses of medical therapy were entered into a prospective randomized trial comparing Nissen fundoplication with the Angelchick prosthesis as a primary surgical procedure. The two groups were matched for age, sex, duration of symptoms before surgery, type of medical therapy, pattern of symptom presentation, endoscopic grade of oesophageal inflammation, manometric lower oesophageal pressure and 24-h pH profile. Twenty-five patients were randomized to each of the Nissen fundoplication and Angelchik prosthesis groups. Operation time and hospital stay were similar in both groups. Persistent dysphagia was reported in five of the patients with an Angelchik prosthesis compared with none in the Nissen fundoplication group. Three prostheses were removed because of severe dysphagia while no Nissen fundoplication required revision. No patient with preoperative dysphagia because of stricture reported swallowing difficulties after operation. At clinical assessment at 3, 6, 12 and 24 months after operation, 85-88 per cent of the patients having a Nissen fundoplication were graded Visick 1 or 2 compared with 60-72 per cent of patients in the Angelchik group.

Surgery for gastro-oesophageal reflux: the Angelchik prosthesis compared to the floppy Nissen fundoplication. Two-year follow-up study and a five-year evaluation of the Angelchik prosthesis

Twenty-two patients were followed for 5 years after insertion of an Angelchik prosthesis for gastro-oesophageal reflux (GOR) and the 2-year results compared with a subsequent group of 28 patients treated by floppy Nissen fundoplication. The overall clinical results of the two procedures were equivalent at 2 years (Angelchik Visick 1 and 2, 80%; Nissen Visick 1 and 2, 78%) but the reasons for failure were different. In the Angelchik group failures were due to mechanical problems associated with the device, whereas the Nissen failures were mainly due to recurrent GOR. There were no patients in the Angelchik group with recurrent reflux at 5 years, but between 4 and 5 years postoperatively four patients developed mild dysphagia. The Angelchik prosthesis appears to be as effective as the floppy Nissen fundoplication, but further long-term studies are required before its widespread use can be recommended.

Colo-pericardial and colo-caval fistula. Late complication of colon interposition

We report the first recorded case of a colo-pericardial fistula and of a colo-caval fistula following interposition of colon after resection of the oesophagus.

Therapeutic progress--review XXXIII. Are we making progress in the drug treatment of oesophageal disease?

Oesophageal problems are common. There are three areas where drug treatment can be helpful, namely in the control of gastro-oesophageal reflux and its symptoms, the treatment of oesophageal motility disorders and when oesophageal infection occurs. In this review the management of these three disorders is considered.

The Angelchik prosthesis for gastro-oesophageal reflux: symptomatic and objective assessment

Twenty-three patients with intractable gastro-oesophageal reflux were treated by insertion of the Angelchik antireflux prosthesis. Good symptomatic relief was achieved in over 80% of patients reviewed up to 28 months after operation and there was marked resolution of oesophagitis as seen on endoscopy. Oesophageal manometry and pH studies performed preoperatively and at 3 and 12 months after operation, showed a significant increase in lower oesophageal sphincter pressure with decreased acid reflux. Some technical problems were encountered, but the prosthesis is potentially a simple and effective means of controlling gastro-oesophageal reflux.

Proximal gastric vagotomy in patients resistant to cimetidine

Fifty-seven patients, with chronic duodenal ulceration resistant to cimetidine therapy, underwent proximal gastric vagotomy during the period August 1979 to May 1984. Thirty-five failed to respond to cimetidine in a dose of 1 g/day, whilst 22 relapsed on reduction of dosage to 400 mg daily or on cessation of therapy. Forty have been followed up for a period of 12-53 months (median duration = 28.5 months), and assessed using the modified Visick system. Thirty-four patients (85 per cent) were graded Visick I or II. Four patients (10 per cent) had non-specific upper gastrointestinal symptoms (Visick III). In these patients endoscopy has shown no evidence of recurrent ulceration. Two patients (5 per cent) were graded Visick IV. One had recurrent ulceration on endoscopy. The other developed symptomatic gastro-oesophageal reflux, necessitating further surgery. These results support the view that cimetidine resistance is not a predictor of poor results following proximal gastric vagotomy.

Gastro-oesophageal reflux in pregnancy. Altered function of the barrier to reflux in asymptomatic women during early pregnancy

The object of this study was to investigate the effect of early pregnancy on the competence of the barrier to gastro-oesophageal reflux (GOR). Oesophageal manometry and prolonged intra-oesophageal pH monitoring were carried out in 12 asymptomatic pregnant women and in 7 non-pregnant women. There was no significant difference in mean intragastric pressure between these two groups. However, both mean lower oesophageal sphincter (LOS) pressure and mean barrier pressure (LOS pressure minus intragastric pressure) were significantly lower in the pregnant subjects (16.9 +/- 0.79 mm Hg; 8.69 +/- 0.73 mm Hg) than in the controls (21.5 +/- 1.93 mm Hg; 14.1 +/- 1.22 mm Hg) (p less than 0.01 and less than 0.001, respectively). No significant difference could be demonstrated between the two groups with regard to degree of GOR, although the pregnant women did exhibit a tendency towards more marked reflux. The results indicate a diminution in the barrier to reflux in early pregnancy due to a reduction in LOS pressure, which may be the basis of symptomatic GOR in pregnancy.

Palliative percutaneous transhepatic drainage for inoperable obstructive jaundice

A technique of percutaneous transhepatic drainage under local anaesthesia is described for the relief of intractable pruritus in patients with obstructive jaundice due to inoperable carcinoma. After standard percutaneous transhepatic cholangiography a polyethylene catheter is introduced into one of the large dilated bile ducts and left in situ, thereby establishing external retrograde biliary drainage. The technique has been used successfully in 6 cases with reduction in serum bilirubin levels and relief of pruritus.

Effective of highly selective vagotomy upon the lower oesophageal sphincter

Recently highly selective vagotomy has been suggested as both a cause of gastro-oesophageal reflux and a potential cure. This study was designed to investigate whether this operation produced any change in the resting pressure or the length of the lower oesophageal sphincter in patients undergoing highly selective vagotomy. A group of patients undergoing truncal vagotomy and drainage were also studied for comparison. No alteration in the resting pressure or length of the lower oesophageal sphincter was noted after either operation. It is therefore unlikely that interference with the sphincter is responsible for post-vagotomy reflux.

Benign thyroid inclusions within cervical lymph nodes: an alarming incidental finding

Small clusters of microscopically normal thyroid follicles within cervical lymph nodes are very occasionally encountered during histological examination. We support the view that provided the thyroid gland is not palpable and a technetium thyroid scan is normal, these should be regarded as benign thyroid inclusions and do not represent small metastatic lesions from thyroid carcinoma. We report an example of these inclusions in a cervical lymph node which was removed incidentally during the excision of a branchial cyst in a 25-year-old woman. The inclusion was too small to be noticed macroscopically and consisted of a small aggregation of histologically normal thyroid follicles situated in the subcapsular region of the lymph node.

Relationship between asthma and gastro-oesophageal reflux

Twenty patients with bronchial asthma who also had gastro-oesophageal reflux were investigated. The severity of their reflux was graded using symptom score of heartburn and regurgitation and by the following investigations: barium swallow and meal, fibreoptic endoscopy and biopsy, manometry and pH monitoring of the distal oesophagus, and an acid infusion test. Full lung function studies were performed and patients were entered into a double-blind crossover study using cimetidine to control their reflux in order to assess beneficial effects with respect to their respiratory problems. Eighteen patients completed the study. Significant improvements were seen in reflux and night time asthmatic symptoms, both these indices being measured on a scoring system. Home monitoring of peak flow values showed a statistical improvement for th last peak flow reading of the day. Fourteen patients felt that their chest symptoms had significantly improved during the cimetidine period.

Effect of Nissen fundoplication on competence of the gastro-oesophageal junction

The changes produced by the Nissen fundoplication were measured in 12 patients, who required surgery to control their reflux oesophagitis. The gastro-oesophageal junction of each patient was studied before and three months after operation by station pullthrough manometry and prolonged pH monitoring of the distal oesophagus. All patients were free from reflux symptoms post-operatively. The Nissen fundoplication resulted in a significant increase in the pressure, but not the length, of the lower oesophageal high pressure zone. A greater proportion of this zone was situated in the abdomen postoperatively. Prolonged pH monitoring showed a significant improvement in all the measured indices of acid reflux. Nissen fundoplication restores competence to the gastro-oesophageal junction as judged by manometry and pH monitoring. This kind of study should be performed to document the efficiency of other anti-relfux procedures.

Assessment of the rapid pullthrough technique in oesophageal manometry

The lower oesophageal sphincter pressure was measured by infusion manometry using the rapid pullthrough technique in two studies designed to evaluate this technique. The first study performed was an assessment of its reproducibility in individual subjects on separate occasions. We conclude that the rapid pullthrough technique does not give reproducible results. The second study compared the lower oesophageal sphincter pressure obtained by this technique with that by the standard station pullthrough technique. We conclude that the results are not comparable.

The reproducibility of the station pullthrough technique for measuring lower oesophageal sphincter pressure

The results are presented of two studies of the station pullthrough technique for lower oesophageal manometry. The first part of the work is an assessment of the reproducibility of this technique using both an infused tube system and a system of subminiature, intraluminal strain gauge transducers. The second part of this report describes a study into the effect that the position of the recording hole on the probe may have in relation to the measured pressure for the lower oesophageal sphincter.

The role of IgA in the prevention of bacterial colonization of the jejunum in the vagotomized subject

The efficacy of three mechanisms of defence against jejunal bacterial colonization (i.e. gastric acid, vagal and pyloric integrity and intestinal IgA) has been investigated. Only in subjects with disturbance of all three mechanisms did significant jejunal colonization occur, and this was invariably associated with severe diarrhoea. Clearly normal intestinal IgA is of critical importance in the prevention of jejunal bacterial colonization in the vagotomized subject.

Abdominal apoplexy

Two cases of the rare condition of abdominal apoplexy are described. The two main clincial presentations of this condition are discussed as is the aetiology. It is suggested that selective visceral angiography might prove helpful in preoperative diagnosis.

The place of transthoracic vagotomy in the management of recurrent peptic ulceration

For the successful treatment of recurrent peptic ulceration confirmation of the presence of the ulcer by fibreoptic endoscopy is essential. Further investigation by barium meal and gastric acid secretion studies allows a rational surgical approach to be formulated. This process is illustrated by discussion of the investigative findings and the results of treatment in a series of 20 patients with recurrent peptic ulcer over a 5-year period. In one-half of these patients a second abdominal operation was necessary, but in the other half a transthoracic vagotomy alone gave equally good results.

The evaluation of dumping and diarrhoea after gastric surgery using a physiological test meal

A test meal consisting of food (Galactomin 18), and a barium preparation (Raybar) was given to 47 patients who had undergone truncal vagotomy combined with either antrectomy or gastric drainage, and to five normal subjects. The radiological findings were correlated with the symptomatology. Total gastric emptying was not significantly different between normal controls, post-operative but asymptomatic cases, or those in whom dumping of diarrhoea was provoked. Small intestinal transit was significantly faster in cases of post-cibal diarrhoea than in other groups, and was also more rapid than normal when dumping was provoked. Colonic entry time was also faster than normal in these two groups. Marked dilution of the meal in the small bowel only occurred in the presence of the dumping syndrome. Jejunal interposition prevented the occurrence of dumping and restored the radiological appearances in the intestine to normal. The test meal gave excellent correlation with the patients' symptomatology. The relationship of the findings to the mechanisms of post-cibal diarrhoea and the dumping syndrome is discussed.

IgA deficiency and severe post-vagotomy diarrhoea

Between January, 1969, and December, 1973, 2058 truncal vagotomies were performed in the Merseyside Regional Health Authority area. 14 of these patients subsequently developed severe post-vagotomy diarrhoea and were extensively investigated. 6 were found to have IgA deficiency. It is suggested that antecedent IgA deficiency may account for the varied reported incidence of severe post-vagotomy diarrhoea and that preoperative screening could reduce the incidence of this complication.

Post-prandial changes in PH and electrolyte concentration, in the upper jejunum after truncal vagotomy and drainage in man

The changes in pH and concentration of electrolytes in the jejunal lumen after a hypertonic fluid meal have been studied after truncal vagotomy and drainage, with and without diarrhoea. The results show that, in these respects, there are no specific changes in the jejunal content associated with post-vagotomy diarrhoea, but that these measurements are markedly affected by the completeness of vagotomy, as judged by the insulin test.

Postprandial osmotic and fluid changes in the upper jejunum after truncal vagotomy and drainage in man

The changes in osmotic pressure and the degree of marked dilution in the jejunal lumen after a hypertonic meal, have been studied in patients after truncal vagotomy and drainage, with and without diarrhoea, using an intraluminal intubation technique. The results suggest that neither the emptying of a hyperosmotic load from the stomach, nor its subsequent dilution in the jejunum have an important role in post-vagotomy diarrhoea.

Gastro-oesophageal reflux complicating highly selective vagotomy

An unacceptably high incidence of gastro-oesophageal reflux was observed in a small series of patients with duodenal ulcer who had been treated by highly selective vagotomy. Possibly this is due to an altered angle of entry of the oesophagus into the stomach, and we now routinely narrow this angle at operation.