Search PubMed⌕ Search

Biomedical subjects

A M Dawson

Publications and source records attributed to A M Dawson.

At least 55 records · Page 3Linked to original sources
PubMed1981

IgG1 antibody in milk protects lambs against rotavirus diarrhoea.

Newborn gnotobiotic lambs were fed a diet of diluted evaporated milk supplemented either with normal ewes' milk or with milk obtained from ewes injected parenterally during gestation with rotavirus. Lambs fed 150 ml per day of milk collected 5 days after lambing from normal ewes were susceptible to rotavirus infection and diarrhoea, while lambs fed milk from vaccinated ewes collected either 5 or 12 days after lambing were protected. Analysis of the milk by column chromatography showed the anti-rotavirus activity to be in the fractions containing IgG1.

Animals↗
PubMed1981

Nocturnal growth hormone and gonadotrophin secretion in growth retarded children with Crohn's disease.

Although impaired growth hormone secretion in response to pharmacological stimuli occurs in some growth retarded children with Crohn's disease, its relationship to past and future th is uncertain. We have therefore determined the growth hormone and gonadotrophin response to the physiological stimulus of sleep by continuous venous sampling in five severely gonadotrophin profiles, the mean plasma hormone concentrations during the first five hours of sleep were determined. In three of the five patients, five hour mean growth hormone levels were reduced (3.8, 5.0, and 8.5 mU/l) compared with levels reported previously in normal short children (10-43 mU/l), although the pulsatile pattern of growth hormone secretion was preserved in all. Nocturnal growth hormone secretion was unrelated to the growth velocities of these children during both pre- and post-treatment assessment periods but a significant correlation was found between growth hormone concentration and a disease activity score (r = 0.79, P less than 0.05), suggesting that growth hormone release by the pituitary was influenced by the severity of the disease. Nocturnal growth hormone secretion was also correlated with gonadotrophin secretion (luteinising hormones, r = 0.99, and follicle stimulating hormone, r = 0.96; p less than 0.01) indicating more extensive hypothalamic-pituitary disturbance. These findings suggest that hypothalamic-pituitary function is depressed in growth retarded children with Crohn's disease, but that abnormalities of growth hormone secretion are unlikely to be directly involved in the growth retardation seen in this condition.

Adolescent↗
PubMed1981

Jejunal water and electrolyte secretion induced by L-arginine in man.

In this study a perfusion technique has been used to investigate jejunal secretion in response to the dibasic amino acid L-arginine. L-arginine at 5, 15, and 40 mmol/l in isotonic saline solutions induced net intestinal secretion of water and Na+. The structurally similar dibasic amino acid L-lysine caused net absorption at 5 and 15 mmol/l, and only modest net secretion of water and Na+ at 40 mmol/l, although absorption rates of the two amino acids were similar. D-arginine (15 mmol/l) was without effect on net water and Na+ absorption. L-arginine 15 mmol/l inhibited glucose-stimulated water and Na+ absorption when perfused in the same intestinal segment, but was without effect when perfused in separate jejunal or ileal segments. Parenteral chlorpromazine inhibited L-arginine induced jejunal water and Na+ secretion. Jejunal secretion induced by L-arginine thus appears not to be due to passive osmotic water flow, nor to release of circulating secretagogues. Stimulation of a mucosal secretory process is most likely to be the mechanism.

Adult↗
PubMed1981

Treatment of chronic erosive gastritis with prednisolone.

Short-term oral prednisolone was successfully used in the treatment of four patients with chronic erosive gastritis which had failed to respond to conventional therapies. Symptomatic improvement occurred in all patients during the first week of treatment. Gastroduodenoscopy after two weeks showed that the erosions had healed. Remission has continued in these four patients for two, seven, eight, and nine months without maintenance therapy. This limited uncontrolled study suggests the corticosteroids may be of benefit in patients with chronic erosive gastritis who fail to respond to conventional treatment.

Aged↗
PubMed1981

Non-cirrhotic intrahepatic portal hypertension: A long term follow-up study.

The clinico-pathological features and prognosis of 59 cases of non-cirrhotic portal hypertension seen at one hospital over a 30-year period are described. Diagnosis was made on operative wedge liver biopsy in most cases. All but two had clinical features of portal hypertension and 47 had bled from oesophageal varices. In 53, portal decompression was performed without operative death or variceal rebleeding. Subsequent liver histology in 16 cases up to 18 years after diagnosis showed no change in the majority. The relatively static morphology was reflected in the clinical course. Twenty-two patients have died but only 11 as a result of liver disease or its treatment. Actuarial analysis shows the five year survival to be 90 per cent and the 30-year survival 55 per cent in strong contrast to the grim prognosis for cirrhosis. The infrequency of operative liver biopsies and unfamiliarity with the disease lead to underdiagnosis.

Adolescent↗
PubMed1980

Site of pain from the irritable bowel.

The distribution of pain from the colon was examined in normal subjects and in patients with irritable bowel syndrome (IBS). Colonic pain was induced by inflating a balloon (introduced during colonoscopy) at several sites throughout the colon. The pain was felt predominantly in the central, lower, and left abdomen in nine patients presenting with rectal bleeding and no spontaneous pain. Pain was felt in any part of the abdomen in 48 patients with painful IBS. Distension of the ascending and transverse colon often produced right-sided or upper abdominal pain in patients with IBS and in 29 of the 48 the pain induced was the same in quality and site as their presenting complaint. In addition pain was referred to several, previously undescribed, extra-abdominal sites. Wider recognition of the distribution of colonic pain could prevent unnecessary investigations including laparotomy.

Abdomen↗
PubMed1980

Circulating somatostatin after food and glucose in man.

Using a recently validated radioimmunoassay, changes in circulating somatostatin have been measured in normal subjects after food (a standard breakfast), and oral and intravenous glucose. After the standard breakfast, a clear and sustained rise in plasma somatostatin was seen in all subjects from a mean value (+/-1 SE) of 28 +/- 7 pg/ml to a mean peak value, at 60 min of 57 +/- 11 pg/ml. When glucose was taken by mouth a significant but smaller rise was seen, but intravenous glucose caused no significant change in plasma somatostatin. A rise in circulating somatostatin after feeding has not previously been demonstrated in normal man and it is suggested that somatostatin may have an important endocrine role in the gut.

Adult↗
PubMed1980

Molecular forms of somatostatin in normal subjects and in patients with pancreatic somatostatinoma.

Two patients with somatostatin-secreting pancreatic tumours are described, one presenting with hypoglycaemia due to hyperinsulinism, and the other with Cushing's syndrome due to ectopic ACTH production. When plasma from these patients was subjected to gel chromatography under conditions designed to prevent somatostatin binding to larger proteins, a peak of monomeric immunoreactive somatostatin was observed as well as several large molecular weight forms. These larger forms of somatostatin could be dissociated into monomeric somatostatin by dithiothreitol. Similar studies on plasma obtained from normal subjects also showed heterogeneity of circulating somatostatin. Extracts of tumour tissue from both patients contained predominantly monomeric somatostatin, but only small amounts of high molecular weight somatostatin which differed from the profile seen in plasma. The site(s) of origin of the large molecualr weight forms of somatostatin seen in plasma and their relative biological activities remain to be established.

Adenocarcinoma↗
PubMed1980

Immunoreactive somatostatin changes during insulin-induced hypoglycaemia and operative stress in man.

Little is currently known about the factors controlling somatostatin secretion. A radioimmunoassay has been developed that is sufficiently specific and sensitive to be used for physiological studies of circulating levels in man. During insulin-induced hypoglycaemia a rise in plasma somatostatin was seen in each of ten subjects studies. Although this paralleled the rise in circulating glucagon and growth hormone, no individual relationships were found either between these variables or to any change in cortisol or insulin C-peptide. In contrast no rise in somatostatin was seen during surgical stress. Thus, contrary to expectation, circulating somatostatin levels can be altered by metabolic stimuli. It seems likely that this peptide may serve an endocrine as well as a paracrine role since its modulating effects may occur not only near to but also at a distance from the site of secretion. It is not yet clear whether the somatostatin measured comes from the hypothalamus, any other part of the central nervous system or the gastrointestinal tract.

Adult↗
PubMed1979

Dapsone and severe hypoalbuminaemia. A report of two cases.

Severe hypoalbuminaemia developed in two patients on long-term dapsone treatment for dermatitis herpetiformis. The patients had been treated with dapsone for 3 and 11 years before the syndrome developed and both recovered completely when dapsone was withdrawn. Albumin-turnover studies revealed a great increase in intravascular albumin catabolism and a modest decrease in synthesis.

Adult↗
PubMed1979

Reintroduction of gluten in adults and children with treated coeliac disease.

Twenty-eight patients, thought to have coeliac disease and on gluten free diets, were put on a normal diet to confirm their diagnoses. Nineteen had been diagnosed in adult life (ACD) and nine in childhood (CCD). Patients were assessed on jejunal, morphological, and symptomatic parameters. Eighteen patients with ACD relapsed within seven weeks. Nine patients with CCD relapsed at variable times but five took longer than seven weeks, the longest period beint 10 months. Seven patients had no symptoms despite morphological deterioration during challenge and one patient, with ACD, did not relapse and was HLA B8 negative. This patient with ACD had subtotal villous atrophy on two jejunal biopsies and later showed morphological improvement on a gluten free diet. There was no correlation between the relapse time and time spent on a gluten free diet.

Adolescent↗
PubMed1979

Development and validation of a specific radioimmunoassay for somatostatin in human plasma.

Little is known about the factors controlling somatostatin secretion in man, and data are not available on the changes in circulating levels in various human physiological or pathophysiological states. This is mainly a consequence of the technical difficulties involved in measuring somatostatin in plasma. In the presence of plasma, binding of somatostatin tracer to antibody was consistently decreased by about 20%, and this could not be abolished by the addition of EDTA and aprotinin or by the use of specially prepared somatostatin-free plasma. Furthermore, in the presence of plasma, endogenous somatostatin does not dilute in parallel with synthetic cyclic somatostatin standard. We have, therefore, developed and validated a radioimmunoassay for somatostatin using prior extraction of the peptide onto leached silica glass. Tyrosine-II somatostatin was iodinated using lactoperoxidase and purified on ODS silica. This method is superior to iodination using chloramine-T with CMC cellulose purification, and gives a highly purified preparation with a shelf-life of at least eight weeks. Using this tracer and a specific antiserum, the limit of sensitivity of the assay was 10 pg/ml, with an intra-assay coefficient of variation of 12% (n = 16) and inter-assay coefficient of variation of 15% (n - 10). Parallelism has been demonstrated between standard synthetic cyclic somatostatin and all extracted plasma samples. The mean recovery of exogenous somatostatin from plasma was 78%. The fasting level of immunoreactive somatostatin at 0,900 hours in 40 normal subjects ranged from 17 to 81 pg/ml. Care is needed, however, when comparing these values with those obtained from other laboratories since standard preparations of somatostatin vary considerably in their immunopotency.

Antibody Specificity↗
PubMed1978

Double-blind withdrawal trial of azathioprine as maintenance treatment for Crohn's disease.

51 patients with Crohn's disease who were in good health while taking azathiprine, 2 mg/kg body-weight/day, for at least six months were allocated either to a group in which azathioprine was continued or to one in which a control tablet was substituted. The trial lasted one year unless relapse recurred earlier. The cumulative probability of relapse was nil at six months and 5% (+/-5 S.D.) at a year among those on azathioprine, compared with 25% (+/-9 S.D.) at six months and 41% (+/-11 S.D.) at a year among those in the control group (P less than 0.01). 1 patient in whom azathioprine was continued died of pancytopenia in the fourth month of the trial. Azathioprine is potentially toxic but appears to reduce the relapse-rate in Crohn's disease.

Adult↗
PubMed1978

The social toll of Crohn's disease.

Eighty-five outpatients with Crohn's disease who knew their diagnosis and that the disease was subject to relapse were interviewed. The personalities of the women as measured by the Eysenck personality questionnaire were similar to those of a control group, but the men were more neurotic and introverted. Most patients continued to live optimistic, useful lives; they felt well, continued to work, hoped that their disease would not deteriorate in the future, and often had an improved relationship with their spouse despite less frequent sexual intercourse. We found that the successful adaptation of patients to this chronic disease was more closely related to their personality than to the activity or extent of the disease.

Adolescent↗
PubMed1978

Antibody titres to lamb rotavirus in colostrum and milk of vaccinated ewes.

Ewes were vaccinated two to three weeks prior to mating with a formalin-treated preparation of lamb rotavirus. The colostrum and milk produced by vaccinated ewes after the subsequent pregnancy were shown to contain significantly higher titres of antibody to the virus than did mammary secretions from non-vaccinates. The virus neutralising antibody activity was associated with IgG in both colostrum and milk. However, IgG concentrations in the mammary secretions of vaccinates and non-vaccinates did not differ. It is suggested that vaccination of the dam may be of value in protecting the suckled neonatal lamb against rotavirus infection.

Animals↗
PubMed1978

Diets and stoma function.

Fifty ileostomy and 50 colostomy patients were questioned as to which foods upset their stoma function. Most patients had no problem in finding a suitable diet and 70 per cent would eat any food on occasions, although half the patients found that side effects with particular foods were a nuisance. Only a small range of foodstuffs seemed to produce symptoms in a significant proportion of patients. We feel that no particular foodstuff should be eliminated from a diet without an adequate trial as most patients are able to eat entirely normally.

Adult↗