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Biomedical subjects

M C Barker

Publications and source records attributed to M C Barker.

18 recordsLinked to original sources
PubMed1992

Hepatic perfusion index: a multicentre trial.

The reproducibility and accuracy of the hepatic perfusion index (HPI) was examined by consideration of in vitro and in vivo factors. A phantom was used to simulate liver blood flow and data acquired on nine gamma cameras. Dynamic hepatic scintigraphy was undertaken on 28 patients at two centres and values obtained for the HPI. Results from the phantom study showed good agreement between the nine cameras and also with the HPI values predicted from the measured phantom flow rates. The results of the patient study indicated a high degree of conformity between observers (r = 0.95, S.E = 0.03) but poorer correlation between the HPI values from the two centres (r = 0.67, S.E. = 0.09). These results imply that centres wishing to use HPI clinically should establish their own range of normality.

Blood Flow Velocity↗
PubMed1987

Gastric emptying and clinical outcome after Roux-en-Y diversion.

The results of 48 Roux-en-Y (RY) diversion procedures are reported: 41 were performed as secondary procedures and 7 as part of a primary operation for peptic ulcer. There was no operative mortality, but four patients developed temporary fistulae in the postoperative period and three patients required reoperation. Good clinical results were found when RY diversion was performed as a primary procedure or when the indication for operation was peptic ulceration. The overall results, however, were poor: 24 patients (50 per cent) felt that they had not benefited and 32 patients (67 per cent) remained in Visick grades III or IV. The main cause of failure was gastric stasis, especially of solid food. Gastric emptying studies were carried out after RY diversion in 22 patients, most of whom had symptoms of stasis. Emptying of liquids was found to be normal in most patients, but emptying of solids was delayed, the median t 1/2 for solids being 160 (75-370) min compared with 67 (50-85) min in DU patients. Bilious vomiting improved significantly after RY diversion, but 18 patients (38 per cent) complained of vomiting food and 32 patients (67 per cent) experienced postprandial distress or pain. Loss of the antral mill, vagotomy of the gastric remnant and, perhaps, resistance to gastric emptying by the Roux loop itself may together explain the delay in gastric emptying of solids after RY diversion.

Adult↗
PubMed1986

Effects of a long-acting somatostatin analogue in patients with severe ileostomy diarrhoea.

Proctocolectomy (PC) with small bowel resection may lead to profuse ileostomy diarrhoea which can be difficult to treat. The effect of a recently developed long acting somatostatin analogue (SMS 201-995) on ileostomy output was investigated in 5 patients who had undergone PC and ileal resection (median 120 cm) and who suffered severe diarrhoea (4-7 litres/24 h). Gastric emptying, transit of a standard meal through the small bowel and the amounts of nutrients excreted were simultaneously determined during double blind infusion of SMS (25 micrograms/h) and placebo (isotonic saline 125 ml/h). SMS 201-995 significantly reduced ileostomy output (P less than 0.05) and water excretion (P less than 0.05) and prolonged small bowel transit time (P less than 0.05). Whilst having little effect on gastric emptying, or on the excretion of glucose or nitrogen, fat excretion was significantly increased (P less than 0.05). In two patients subcutaneous administration of SMS 201-995 (50 micrograms b.d.) has maintained a reduced ileostomy output for 4 and 6 months respectively.

Body Water↗
PubMed1984

The effect of resection of the distal ileum on gastric emptying, small bowel transit and absorption after proctocolectomy.

Patients who had undergone proctocolectomy and ileostomy for ulcerative colitis have been studied. One group (contrast group) had undergone resection of only small amounts of terminal ileum (median = 4 cm), the other group of patients (study group) had undergone resection of greater lengths of small bowel (median = 60 cm). Gastric emptying and transit of a standard meal through the small bowel were estimated, whilst the amounts of fat, nitrogen, glucose, sodium and potassium excreted by the ileostomy were simultaneously determined. Significantly greater amounts of fat, nitrogen, sodium, potassium and water were excreted by patients who had undergone resection compared with contrast patients (P less than 0.01). The rate of gastric emptying was not increased in patients who had undergone ileal resection compared with contrast patients but small bowel transit within 4 hours of ingestion of the meal was significantly faster. A significant correlation between transit times and excretion of fat was also noted in patients (P less than 0.02). Thus, quite modest ileal resection in addition to proctocolectomy leads to rapid small bowel transit and marked malabsorption of nutrients as well as water and electrolytes.

Adolescent↗
PubMed1984

The effect of in-vivo dispersion and gastric emptying on glibenclamide absorption from a novel, rapidly dissolving capsule formulation.

The in-vivo dispersion and gastric emptying of a novel glibenclamide dose form have been investigated using gamma-scintigraphy and related to the absorption of glibenclamide determined by measuring glibenclamide plasma concentrations. Its absorption is determined by the rate of emptying of the dose form from the stomach with the lag time between dosing and the start of gastric emptying (and hence absorption of the dose) largely dependent on the in-vivo disintegration time. The presence of food in the stomach has a marked effect on in-vivo disintegration/dispersion of the dose form and hence on the lag time between dosing and the start of absorption.

Adult↗
PubMed1983

Gastrointestinal transit of liquids.

A simple, non-invasive technique has been established for the simultaneous measurement of stomach emptying and the small bowel transit of a liquid meal. The rate of gastric emptying (T1/2) was measured in 21 normal subjects by using a gamma camera and computer to observe emptying of 200 ml of water to which 200 muCi 99Tcm - diethylene tetramene pentacetic acid chelate was added. By adding lactulose to the drink and measuring breath hydrogen (H2) concentration, small bowel transit time (Ta) was simultaneously estimated. There was no significant correlation (r = 0.26, P greater than 0.2) between T1/2 and Ta or between T1/2 and the shape of the breath H2 evolution curve. However, the shape of the breath H2 curve did seem to be affected by Ta. The technique should prove useful for the study of gastrointestinal motility in disease states.

Disaccharides↗
PubMed1979

Proximal stomach and antrum in stomach emptying.

In a series of measurements of liquid-phase gastric emptying using a radionuclide marker on 35 subjects, five were identified in whom the proximal stomach and antrum were clearly distinguishable. Three of these subjects were normal controls and two suffered from systemic sclerosis. In the three normal subjects, analysis of the movement of the liquid showed the expected movement from fundus to antrum and thence through the pylorus. In the two patients with systemic sclerosis, there was, in contrast, evidence of mass retropulsion of the contents of the antrum into the fundus. In such cases, the measurement of stomach emptying based on the assumption of a single-compartment system in likely to be misleading.

Gastric Emptying↗
PubMedDate not supplied

A theoretical analysis using ratios of the major elements measured by neutron activation analysis to derive total body water, protein, and fat.

A theoretical analysis based upon Reference Man is used to derive the water, protein, and fat components of soft tissue using the ratios of carbon/oxygen and nitrogen/hydrogen determined by in vivo neutron activation analysis and measurement of body mineral content by dual energy x-ray absorptiometry. The standard deviations in the estimates of water, protein, and fat are 0.58, 0.59, and 0.53 kg, respectively, if the reproducibility measurement of the carbon/oxygen ratio is 2.5% and of the nitrogen/hydrogen ratio is 5%, the accuracy of measurement of bone mineral is 4%, and estimate of glycogen is 0.5 kg. New neutron activation technology may permit sufficiently precise measurements.

Adipose Tissue↗