Biomedical subjects
Publications and source records attributed to M Critchley.
The aim of this study is to determine whether white blood cell imaging in inflammatory conditions is due to a blood pool effect as a result of an increased vascularity and vascular permeability, or whether cellular migration is the major contributing factor. It will be shown that white cell uptake is a specific phenomenon in the rheumatoid knee joint and not just a blood pool effect.
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Gastric emptying of liquid was studied in 10 normal volunteers and in 27 patients previously treated with truncal vagotomy and drainage. Thirteen of the twenty-seven patients complained of persistent postvagotomy diarrhoea. For each study 300 ml 15 per cent dextrose, labelled with 99mTc-diethylene triamine penta-acetic acid (DTPA), was ingested at a standard rate by subjects who sat facing a gamma camera. Imaging proceeded for 30 min. Gastric area activity curves were corrected for emptying of the test meal during ingestion, and for movement using a new image alignment technique. Gastric emptying at 15 min was 10 +/- 2.6 per cent (mean +/- s.e.m.) in healthy volunteers, 48 +/- 7.3 per cent in patients without diarrhoea, and 84 +/- 2.3 per cent in those with diarrhoea (P less than 0.001, ANOVA). Gastric emptying from 15 min onwards was slower than normal in both patient groups (P less than 0.001). These results show that initial gastric emptying is rapid following truncal vagotomy and drainage, and this change is greater in patients with postvagotomy diarrhoea. No patient with diarrhoea had normal initial gastric emptying.
The existence of preduodenal phases of gallbladder emptying in normal volunteers was investigated by evaluating the effect of sham feeding a sandwich (chew and spit) (n = 15), the sight and smell of food followed by sham feeding a cooked meal (n = 15), and gastric distension (intragastric balloon tube) (n = 9) on gallbladder emptying and comparing these responses with those after ingestion of a standard meal (n = 14). A control group given no intestinal stimuli were studied to determine the frequency of spontaneous emptying during fasting (n = 18). 99mTc-EHIDA (2,6 diethylphenylcarbamoylmethyliminodiacetic acid) was used as the biliary tracer. The frequency of gallbladder emptying during fasting was 0.0045/min. Thus, in any 20 min period emptying occurred spontaneously in only about 1 in 11 volunteers. Significant emptying (greater than 5 per cent over 20 min) occurred in 8 out of 15 volunteers after sham feeding a sandwich (P less than 0.001 versus control), in 8 out of 15 volunteers after sham feeding a cooked meal (P = 1.0 versus sandwich sham feed, n.s.), in 6 out of 9 volunteers after gastric distension (P less than 0.001 versus control) and in 14 out of 14 volunteers after meal ingestion. The rate of emptying was significantly greater in the gastric distension and meal ingestion groups compared with other groups (P less than 0.05). However, the emptying rate after sham feeding was not significantly different from spontaneous gallbladder emptying (P greater than 0.05, n.s.). There was no significant difference in time to onset of emptying between the four stimulus groups (P greater than 0.05, n.s.). These results suggest that pre-duodenal stimuli can evoke gallbladder emptying in man, although the precise physiological significance of this phenomenon remains to be established.
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1. The cellobiose/mannitol and 51Cr-labelled ethylenediaminetetra-acetate (51Cr-EDTA) absorption tests have been compared with respect to their ability to detect altered intestinal permeability in coeliac disease. 2. In patients with clinically proven coeliac disease, 13 out of 14 (93%) had abnormal urinary cellobiose/mannitol ratios, while only five out of 12 (42%) had abnormal urinary recoveries of 51Cr-EDTA. Thus, the cellobiose/mannitol absorption test is more sensitive in recognizing coeliac disease and this difference was significant (P less than 0.02). 3. Possible reasons for this difference in the sensitivity of the two absorption tests are discussed.
The pattern of gastric emptying after truncal vagotomy and drainage is usually biphasic. An early rapid phase is followed by a characteristically abrupt transition to slow emptying. The mechanisms responsible for this pattern were studied in six dogs with truncal vagotomy and pyloroplasty, fitted with a proximal duodenal cannula. Gastric emptying was measured using gamma camera imaging of a radiolabelled 15% dextrose test meal. Sixty one hour studies were done using five designs. (1) With the cannula closed gastric emptying was initially rapid, followed by stasis (emptying at 15 min - 32% (5.3), 60 min - 34% (4.8); mean (SE)). (2) With the cannula open emptying was very rapid (15 min - 76% (4.2) p less than 0.001, 60 min - 88% (2.6) p less than 0.001 ANOVA). (3) Distal duodenal instillation of isotonic saline, at a rate equivalent to gastric emptying with the cannula closed, did not retard this rapid emptying (15 min - 78% (10.6), 60 min - 90% (5.4)). (4) With duodenal instillation of 15% dextrose, gastric emptying remained faster than in studies without diversion (15 min - 50% (7.0) NS, 60 min - 65% (6.8) p less than 0.01), but was slower than during diversion alone (p less than 0.05). (5) Finally, duodenal instillation of 15% dextrose before administration of the test meal produced slower initial emptying without subsequent stasis (15 min - 24% (4.5), 60 min - 47% (10.6)), although the amounts emptied were not significantly different from those with the cannula closed. These results indicate that after truncal vagotomy and pyloroplasty small bowel resistances play a significant role in controlling gastric emptying. Osmoreceptor responses persist after truncal vagotomy, but sympathetic inhibitory responses to small bowel distension are not involved in the regulatory process.
Gastric emptying was measured in 12 patients with chronic duodenal ulceration and compared with the results from 10 healthy volunteers. The test meal of 300 ml 15% dextrose, labelled with 99mTc-DTPA, was ingested in increments over 6 min. Gamma camera imaging proceeded over 30 min, with a 1-min frame time. A direct correction was applied for the fraction emptying into the small bowel during the ingestion period. Gastric emptying at 6 min was significantly greater in the group with duodenal ulcer (14.4 +/- 2.7% vs. 4.2 +/- 0.9%: mean +/- SEM, p less than 0.01). From this time onwards there were no significant differences in the rates of gastric emptying. These results suggest that chronic duodenal ulcer is associated with an abnormal pattern of gastric emptying of liquid, characterised by an initial rapid phase.
187 patients, euthyroid for more than a year after radioiodine treatment for hyperthyroidism, were studied for 10 years; 81 (43%) became hypothyroid. The incidence of hypothyroidism was lower in patients initially presenting with large thyroids (28%) or with nodular thyroids (22%) and in those without thyroid autoantibodies (31%). During follow-up, an elevated serum TSH was present in all 81 patients when they became hypothyroid (sensitivity and negative predictive value 100%), and was present for at least a year in 98% of these. However, an elevated serum TSH was also present in 48% of 106 patients remaining euthyroid (positive predictive value 61%). FT4I was low in 94% of patients who became hypothyroid and normal in 80% of patients who remained euthyroid (positive predictive value 78%, negative predictive value 93%). Serum TSH and FT4I were the best biochemical predictors. FT3I and serum cholesterol were less satisfactory. A palpable thyroid becoming impalpable, though readily assessed, was limited in usefulness. Clinical appraisal remains important and a progressive, though perhaps less rapid, later increase in the incidence of hypothyroidism appears likely.
SPECT of the spleen has been performed with 99Tcm-sulphur colloid in 53 patients, and SPECT of the liver has been performed in 57 patients. All patients had histologically proven liver disease and were classified by the degree of severity, Group A-severe, Group B-moderate, Group C-mild. The patients were further classified as cirrhotic and non-cirrhotic. Eight controls were also studied. There is positive though poor correlation between splenic volume and uptake (r2 = 0.55). Splenic volume and uptake are significantly different in Group A patients compared with all other groups (p less than 0.001). They are also significantly different in cirrhotics versus non-cirrhotics and cirrhotics versus controls (p less than 0.001). Splenic SPECT was unhelpful in distinguishing between moderate and mild liver disease. SPECT of the spleen is a time consuming technique but a useful adjunct to liver SPECT in patients with portal hypertension.
Dynamic hepatic scintigraphy was performed in a group of cirrhotic patients to evaluate the optimum imaging and analytical procedures necessary for the measurement of the hepatic perfusion index (HPI). Patients were studied in the posterior (n = 19) and the anterior (n = 14), positions, with either 0.2 or 0.5 ml of 99Tcm sulphur colloid administered as a rapid bolus injection. In each subject, three ROIs (small, medium and large) were drawn over the liver, and time-activity perfusion curves were generated. Analytical techniques were developed to allow flexibility in selecting the arterial and portal venous phases of the liver perfusion curve. The quality of the bolus, expressed as the full width at half-maximum of the left ventricular time--activity curve, was independent of the bolus volumes and patient positioning. The dispersion in the data and the inter-observer variation were less in the anterior view using medium and large ROIs, compared with the anterior small ROI and all the posterior ROI sizes. A time delay between liver and kidney arterial phases, if ignored, produced statistically significant effects on the values of the HPI. We conclude that HPI investigations are best performed in the anterior projection. Data analysis using a large liver ROI is preferred, and flexible data-processing techniques are recommended, particularly in the presence of a liver and kidney arterial time delay.
Little is known of the temporal and quantitative relationships between emptying of the stomach and of the gall bladder in patients with duodenal ulcer before and after vagotomy. A non-invasive double isotope technique was used to investigate these relationships in 27 patients with a duodenal ulcer, before and after operation-truncal vagotomy and pyloroplasty (TV + P; n = 15) and highly selective vagotomy (HSV; n = 12). A further 25 patients were studied after operation (TV + P, n = 20: HSV, n = 5). 99Tcm-EHIDA was used as the biliary tracer and 113Inm bran as the gastric content tracer. In patients with a duodenal ulcer before surgery and in 16 of the 17 patients studied after HSV, the patterns of gall bladder emptying were similar to those previously found in normal subjects. In 60% of patients after TV + P, patterns of gall bladder emptying were altered and the onset of gall bladder emptying was significantly delayed (p less than 0.001) compared with unoperated patients and patients with a HSV. The rate of gall bladder emptying did not correlate with the rate of gastric emptying in any of the patients studied. These observations suggest that TV + P, but not HSV, causes considerable alteration in coordination of gall bladder and gastric emptying.
Osmoreceptors in the upper small bowel may delay gastric emptying by inhibiting fundal tone and/or by increasing outflow resistances. In this study we examined the contribution of postpyloric resistances to this braking system. Seven dogs had gastric emptying of 250 ml 15% dextrose, labelled with 99mTc-DTPA, measured by gamma camera imaging (preoperative studies: n = 21). A proximal duodenal cannula was inserted and studies repeated in four modes: with the cannula closed (n = 14); with total diversion of gastric effluent through the cannula (n = 7); with diversion and downstream reinstillation of effluent at a constant rate (n = 14) equivalent to emptying calculated from studies without diversion; and with diversion and total reinstillation of effluent (n = 14). Gastric emptying at 90 minutes was similar in preoperative studies (48 +/- 5% - mean +/- SEM) and in those with the cannula closed (50 +/- 3%). By comparison 'total diversion' produced rapid emptying over 90 minutes (97 +/- 1%; p less than 0.001). Reinstillation of effluent at a constant rate reduced the 90 minute emptying to 59 +/- 6%, and total reinstillation slowed emptying further to 37 +/- 4% (p less than 0.05). Neither reinstillation protocol yielded gastric emptying rates that were significantly different from those in studies without diversion. With total reinstillation, emptying and hence reinstillation rates were more variable, proceeding in a step and plateau fashion. We conclude that canine jejunal osmoreceptor activity is mediated through the stomach, with postpyloric resistances playing little or no role. Gastric emptying curve analysis suggested that increments of rapid small bowel filling provoke exaggerated braking responses.
This article is a brief account of the personality of Hughlings Jackson, his mode of life, and his intimate friends. He grew up when worldwide developments were taking place in biological thinking. The philosopher Herbert Spencer impressed him with his exciting concept of evolution, a principle which Jackson realized was applicable to the functions and disorders of the nervous system. Jackson and Spencer corresponded over a period of at least 37 years but they were not friends, their personal qualities being very different. Revered by his colleagues, even though they may not have fully understood what he was trying to say, Jackson became a legend in his own lifetime and an inspiration to neurologists who succeeded him.
A murine monoclonal antibody, H317, specific for placental-type alkaline phosphatase was labelled with 123I and assessed as an imaging agent using a gamma camera computer system in 18 patients suspected of possible recurrent or metastatic ovarian cancer 1-4 years after removal of the primary tumour. Four patterns of distribution were visible: (1) normal uptake; (2) focal accumulation; (3) diffuse uptake; and (4) 'cold' areas. Six patients, five of whom were clinically negative for ovarian cancer, had normal scans; 11 patients, eight of whom were clinically positive, had increased uptake. One patient had visibly 'cold' areas. Findings were confirmed, where possible, at surgery.
A false-negative In-111 WBC scan was obtained in a case of a large, infected hemophiliac pseudotumor. Following aspiration of the abscess, a positive scan was seen, demonstrating that In-111 WBC imaging occasionally may be misleading as a diagnostic tool.
Forty-four patients with symptoms of lower limb arterial insufficiency were examined by radionuclide angiography using 99Tcm in vivo red cell labelling and by contrast aortography. The results of the study indicate that radionuclide angiography may well have a useful role to play in determining the type of contrast study most appropriate for delineating the aortic-iliac segment.