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Biomedical subjects

J R Thornton

Publications and source records attributed to J R Thornton.

At least 37 records · Page 2Linked to original sources
PubMed1988

Is ascites caused by impaired hepatic inactivation of blood borne endogenous opioid peptides?

Methionine enkephalin and catecholamines were measured in carefully collected plasma samples from 25 patients with cirrhosis and ascites, and 25 with cirrhosis without ascites, 15 disease and 15 healthy controls. Methionine enkephalin was invariably raised in the ascites group, the median value being 4.6-6.9 times that of the other three groups. Similarly, in the ascites group, median noradrenaline was increased 2.5-4.2 and median adrenaline 1.8-2.5 times that of the other groups. Plasma methionine enkephalin is considerably raised in patients with cirrhotic ascites and has actions which could enable it to be an initiating factor of ascites formation.

Ascites↗
PubMed1988

Do increased catecholamines and plasma methionine enkephalin in cirrhosis promote bleeding oesophageal varices?

Increased sympathetic tone and adrenal medullary activity in hepatic cirrhosis may promote portal hypertension. We suggest that they may be imperfect homeostatic mechanisms attempting to maintain systemic arterial pressure in response to chronic vasodilatation and that small, endogenous opioid peptides may play a part in this vasodilatation. As initial investigation of this hypothesis, we measured noradrenaline (an indicator of sympathetic tone), adrenaline and methionine enkephalin in the plasma of patients with cirrhosis with oesophageal varices which had or had not bled previously, patients with cirrhosis without varices, patients with acute liver disease and controls. In patients with cirrhosis, noradrenaline, adrenaline and methionine enkephalin were all greatest in those with oesophageal varices which had previously bled. In this group, noradrenaline correlated strongly with the widely used prognostic guide, Pugh's modification of Child's classification. In patients with acute liver disease, methionine enkephalin and adrenaline were increased six- and four-fold respectively. However, noradrenaline was normal, suggesting that increased sympathetic tone in cirrhosis may develop gradually. The use of opioid antagonists may enable determination of whether elevated plasma opioid peptides in cirrhosis stimulate the increase in sympathetic tone and plasma adrenaline, and promote bleeding oesophageal varices.

Acute Disease↗
PubMed1987

Super-efficient starch absorption. A risk factor for colonic neoplasia?

We tested the hypothesis that super-efficient starch absorption, by reducing the supply of carbohydrate to the colon, may be associated with and possibly promote colonic neoplasia. By means of breath hydrogen measurements following a potato meal and comparison with the hydrogen response to lactulose, the amount of starch escaping small bowel absorption was measured in 10 patients who had a colonic adenoma removed endoscopically and in 10 controls. The subjects' consumption of starch and fiber was assessed. Percentage unabsorbed starch was approximately half as much in the patients (5.3%) compared with the controls (10.9%, P less than 0.05). Consumption of starch and dietary fiber, and mouth-to-cecum transit times were not significantly different. Unabsorbed starch was calculated to contribute to 6.0 g/day colonic carbohydrate in the patients and 10.9 g/day in the controls (P less than 0.05). This study confirms that unabsorbed starch provides an important quantity of colonic carbohydrate and suggests that super-efficient starch absorption, by reducing this provision, may promote colonic neoplasia.

Breath Tests↗
PubMed1986

Does super efficient starch absorption promote diverticular disease?

The amount of starch escaping absorption in the small intestine was measured in eight patients with symptomatic diverticular disease and eight controls. Unabsorbed starch was calculated from breath hydrogen measurements after a potato meal compared with the hydrogen response to lactulose. The proportion of unabsorbed starch was low in all the patients (mean 3.3%) and was only about a quarter of that in the controls (12.4%; p less than 0.01). These findings confirm that unabsorbed starch provides an important quantity of carbohydrate reaching the colon and suggest that super efficient starch absorption, by reducing this provision, may promote the development of diverticular disease.

Aged↗
PubMed1985

Hormonal responses to exercise and training.

Current knowledge and understanding of the hormonal response to exercise are limited, whether in relation to horses, humans, or other species. The changes in plasma concentration of some hormones occur early in exercise, apparently owing to a neuronal stimulation, whereas others, being pituitary dependent, require hormonal stimulation. Also, although it is possible to observe changes in plasma concentrations of hormones, the mechanism by which this is achieved is not always understood, and unless the nonprotein-bound, or active, form of the hormone is also determined, changes in plasma concentration are less informative. Both the intensity and duration of exercise may be of importance in initiating or maintaining the hormonal response. Impulses from either the working muscles or motor centers, via the central nervous system, modify the response of the glands of the endocrine system directly via pituitary hormones or indirectly via the sympathoadrenal system. The initial response to the onset of exercise is enhancement of sympathoadrenal activity and secretion of pituitary hormones, which result in a reduction in the plasma concentration of insulin and a rise in that of virtually all other hormones. Because of this shift in hormone balance, a modification of the metabolism of intra- and extra-muscular triglycerides and glycogen as fuels for muscular exercise occurs. The variation in mobilization of one fuel source may well influence its combustion, together with both the mobilization and combustion of the other. When exercise is prolonged, the hormonal response is influenced by additional factors such as temperature, glucose availability, oxygen tension, and changes in plasma volume. The effect of training on hormonal responses is generally an ameliorating one that reflects an increased efficiency of muscular energy metabolism as a result of the training process.

Aldosterone↗
PubMed1985

Exercise testing.

In the athletic horse, an exercise test may be required to measure the adaptation of the animal to a specific training program; to modify the training program in response to the progress achieved; to investigate the reasons for failure to perform at the expected level; and to form part of an overall clinical examination of a horse with a specific disability. This article includes information on the scope and form of an exercise test, the parameters measured during the test and their interpretation, treadmill and track tests, and the clinical applications of exercise tests.

Animals↗
PubMed1984

Atrial fibrillation in healthy non-alcoholic people after an alcoholic binge.

After alcoholic binges, atrial fibrillation developed in four people who usually drank little or no alcohol. All spontaneously reverted to sinus rhythm within a day. Investigations revealed no evidence of underlying disease or cardiac abnormalities. They were advised to avoid excessive alcohol intake, and an average of two years later none has had a further attack of atrial fibrillation.

Adult↗
PubMed1983

Diet and gall stones: effects of refined and unrefined carbohydrate diets on bile cholesterol saturation and bile acid metabolism.

It has been suggested that consumption of refined carbohydrate foods (notably sugar and white flour) increases bile cholesterol saturation and hence the risk of cholesterol gall stone formation. To test this hypothesis, 13 subjects with probable cholesterol gall stones ate refined and unrefined carbohydrate diets, each for six weeks in random order. On the refined carbohydrate diet, subjects ate more refined sugar (mean = SEM: 106 +/- 7 vs 6 +/- 1 g/day, p less than 0.001), less dietary fibre (13 +/- 1 vs 27 +/- 3 g/day, p less than 0.001), and had a higher energy intake (9.17 +/- 0.66 vs 7.16 +/- 0.64 MJ/day, p less than 0.001). After each diet, the lipid composition of duodenal bile and bile acid kinetics was determined. The cholesterol saturation index of bile was higher on the refined carbohydrate diet in all but one subject, with a mean value of 1.50 +/- 0.10 compared with 1.20 +/- 0.12 on the unrefined diet (p less than 0.005). On the refined carbohydrate diet, bile contained relatively less cholic acid and slightly more deoxycholic acid. There were, however, no significant differences in total or individual bile acid pool sizes. There were also no differences in the rates of primary bile acid synthesis or fractional turnover on the two diets. Consumption of carbohydrate in refined form increases bile cholesterol saturation. The risk of gall stones might be reduced by avoidance of refined carbohydrate foods.

Adult↗
PubMed1983

Empyema of the gall bladder - reappraisal of a neglected disease.

Thirty two patients with empyema of the gall bladder were identified among 1327 cases of gall-bladder disease presenting to one hospital over a six year period. Abdominal pain had been present for a median of eight days and, in eight cases, for between one and four months. In a few cases, the disease was painless and was discovered unexpectedly at postmortem or at operation for unrelated disease. The serious nature of the complaint was belied by the often scanty physical signs. Less than half the patients had a pyrexia of more than 37.5 degrees C and the presence of sepsis was rarely suspected clinically. Eight patients (25%) died, usually from unsuspected septicaemia. This considerable mortality might be reduced by the wider use of blood culture in cases of apparent 'cholecystitis' and by greater awareness that empyema of the gall bladder is sometimes chronic, painless, and afebrile.

Abdomen↗
PubMed1983

Not just fibre--the nutritional consequences of refined carbohydrate foods.

The dietary intake of 28 volunteers was assessed over two 6-week periods while they ate, alternately, a diet containing refined carbohydrate foods in commonly consumed amounts and a diet virtually devoid of such foods. The following nutritional effects of refined foods were observed: increased energy intake (except in low consumers of sugar), decreased intake of dietary fibre, and decreased intake of nearly all the vitamins and minerals recorded in tables of food composition. These effects may have harmful consequences.

Adult↗
PubMed1981

A relation between high-density-lipoprotein cholesterol and bile cholesterol saturation.

The association of cholesterol gall stones with coronary artery disease is controversial. To investigate this possible relation at the biochemical level, bile cholesterol saturation and the plasma concentrations of triglycerides, total cholesterol, and high-density-lipoprotein cholesterol (HDL cholesterol) were measured in 25 healthy, middle-aged women. Bile cholesterol saturation index was negatively correlated with HDL cholesterol. It was positively correlated with plasma triglycerides and with total cholesterol minus HDL cholesterol. These findings provide a biochemical basis for a positive association in women between cholesterol gall stones and coronary artery disease.

Adult↗
PubMed1981

High colonic pH promotes colorectal cancer.

Considerable evidence suggests that the carcinogens or co-carcinogens responsible for the development of colorectal cancer are either bacterially degraded bile acids or cholesterol. It is proposed that a high colonic pH promotes co-carcinogen formation from these substances and that acidification of the colon either by dietary fibre (following its bacterial digestion to short-chain fatty acids) or milk (in lactose-intolerant individuals) may prevent this process.

Bacteria↗