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Biomedical subjects

A Ferguson

Publications and source records attributed to A Ferguson.

At least 217 records · Page 12Linked to original sources
PubMed1985

Efficacy of the ejector flow-meter. A scavenging device for anaesthetic gases.

Measurements of air concentrations of nitrous oxide and halothane in the breathing zone of the anaesthetist and the operating-room nurse were carried out during inhalation anaesthesia with a Mapleson D system. Gas removal was performed from inside the breathing system at the same rate as that of the fresh gas inflow by means of an ejector flow-meter. The concentrations of nitrous oxide and halothane were maintained below the Danish Threshold Limit Values of 100 and 5 parts per million, respectively, by using this type of scavenging. When these anaesthetics were used simultaneously, the reduced Threshold Limit Values were not exceeded during endotracheal anaesthesia.

Air Pollutants, Occupational↗
PubMed1985

Histochemical demonstration of chymotrypsin like serine esterases in mucosal mast cells in four species including man.

Serine esterases were detected in the granules of mucosal mast cells from rat, mouse, sheep, and man. Successful demonstration of enzyme activity required brief fixation (6 h) of tissues in 4% paraformaldehyde. Staining with naphthol AS-D chloroacetate produced an intense red reaction product in intraepithelial mucosal mast cells (globule leucocytes) and mucosal mast cells within the lamina propria of the gastrointestinal tract. The mast cell identity of cells stained for esterase was confirmed by sequential staining with toluidine blue (pH 0.5). Furthermore, the numbers of cells detected after staining for esterases or with toluidine blue were highly correlated. Esterase activity within mucosal mast cells/globule leucocytes from all species was inhibited with the serine enzyme inhibitor phenylmethylsulphonyl fluoride. Further histochemical studies with the substrate, N-acetyl-DL-phenylalanine B-naphthyl ester, indicated that mucosal mast cells and globule leucocytes contain esterases which are chymotrypsin like in substrate specificity.

Animals↗
PubMed1985

Prevention of oral tolerance induction to ovalbumin and enhanced antigen presentation during a graft-versus-host reaction in mice.

Systemic hyporesponsiveness after ingestion of a protein antigen (oral tolerance) depends on antigen processing by the gut and the actions of immunoregulatory T cells. We have examined the effects of a graft-versus-host reaction (GvHR) on oral tolerance, since both immune status and intestinal function are altered in GvHR. The GvHR was induced in unirradiated (CBA X BALB/c)F1 mice by intraperitoneal injection of CBA spleen cells. The tolerance of systemic humoral immunity and of delayed-type hypersensitivity normally found in mice fed 25 mg ovalbumin (OVA) was partially abrogated from 1 to 3 weeks after induction of the GvHR. In addition, mice with GvHR had a persistent enhancement of systemic immunity to OVA, and this was associated with an augmented ability of spleen cells to present OVA to primed T cells. The phagocytic activity of the reticuloendothelial system, as established by carbon clearance tests, was not altered by the GvHR. These findings suggest that enhanced antigen-presenting cell activity interferes with the induction of oral tolerance, and may be another pathogenetic mechanism of intestinal hypersensitivity disease.

Administration, Oral↗
PubMed1984

Comparison of cognitive ability, personality profile, and school success in epileptic children with pure right versus left temporal lobe EEG foci.

By reviewing electroencephalographic reports compiled over five years and checking clinical details, we identified and studied 27 children with apparently pure left or pure right temporal lobe epilepsy. The children underwent neurological examination and neuropsychological testing (Halstead-Reitan Battery, Wechsler Intelligence Scale for Children [WISC] and Wide Range Achievement Test), and parents completed the Personality Inventory for Children (PIC). Of 15 boys and 12 girls with a mean age of 12.7 years, 14 had right and 13 left temporal lobe epilepsy. Seizure control was excellent in 17. Five (2 with left, 3 with right temporal lobe epilepsy) had received professional emotional help, 6 (3 with left, 3 with right focus) received special help at school, and 5 (3 with left, 2 with right focus) had failed a grade in school. No significant left-right differences were seen in WISC full scale, verbal, or performance IQ scores, neuropsychological test battery findings, or clinical scale scores on the PIC. Most of the children with unilateral temporal lobe epilepsy had no measurable cognitive or emotional difficulties. Cognitive, personality, and school problems were equally distributed between left and right temporal lobe epilepsy groups. When the two groups were combined, however, 10 patients (5 with left, 5 with right focus) were identified by the PIC as maladjusted, and as a group showed significantly lower neuropsychological test functioning than did the normally adjusted children.

Achievement↗
PubMed1984

Cellobiose/mannitol sugar permeability test complements biopsy histopathology in clinical investigation of the jejunum.

Intestinal permeability to probe molecules has been shown to correlate closely with the presence or absence of villous atrophy in a jejunal biopsy. The purpose of this study was to establish if there exist groups of patients with functional derangement of intestinal permeability but normal histopathology of the small bowel mucosa. In 135 patients a cellobiose/mannitol permeability test was performed at the same time as jejunal biopsy. Diagnosis included coeliac disease, Crohn's disease, irritable bowel syndrome, idiopathic diarrhoea, self diagnosed food allergy, atopic eczema and postinfectious malabsorption. The value of the cellobiose/mannitol test in identifying patients with abnormal jejunal biopsy histopathology was confirmed. The permeability test was abnormal in all 28 patients with partial or subtotal villous atrophy, and also in all 10 in whom there was a high intraepithelial lymphocyte count despite normal villi and crypts. Functional abnormality of the small intestine has not previously been reported in patients with this jejunal biopsy abnormality. Abnormalities of permeability were also found in patients with idiopathic diarrhoea, folate deficiency, postinfectious or traveller's diarrhoea, small bowel Crohn's disease, and atopic eczema. These results show that sugar permeability tests have more potential in clinical investigation than merely serving as screening tests before jejunal biopsy. There are groups of patients without morphological changes in the small bowel in whom intestinal permeability is abnormal.

Adolescent↗
PubMed1984

Prevalence of lactase deficiency in British adults.

The prevalence of lactase deficiency in British adults is unknown. Examination of the distribution of lactase activities in single and multiple biopsies of jejunum indicated that 0.8 U/g wet weight was a suitable cut-off point to separate lactase deficient patients from others. One hundred and fifty white British adults were selected, none of whom had significant intestinal disease and all of whom had normal histopathology of a jejunal biopsy and normal activities of other disaccharidases measured in the biopsy. The prevalence of lactase deficiency in this group was 4.7%. In contrast, 15 of 20 non-white adults were lactase deficient. Lactase deficiency was found in only three of 36 patients investigated because of diarrhoea after gastric surgery, and in 16 of 200 patients with irritable bowel syndrome (8%). As the prevalence of lactase deficiency is no higher in irritable bowel syndrome than in 'normal' individuals, lactase deficiency clearly is not a predisposing factor for irritable bowel syndrome in white British adults although the two conditions may occasionally coexist.

Adult↗
PubMed1984

Immune responses to fed protein antigens in mice. 3. Systemic tolerance or priming is related to age at which antigen is first encountered.

The normal effect of feeding an antigen, such as ovalbumin (hens' egg albumin), to adult animals is the induction of a state of specific nonreactivity of the lymphoid tissues when the same antigen is presented again (oral tolerance). We have carried out feeding experiments in neonatal mice to investigate subsequent immune responses after physiologic antigen exposure and to examine the role of the neonatal intestine. We demonstrate for the first time that feeding a weight related dose of ovalbumin within the first week of life results in priming for both humoral and cell-mediated immune responses, despite the profound tolerance found in adult animals when treated in the same way. When the time scale of antigen exposure was extended into the prenatal period, the enhancement of the immune response was even more pronounced. These effects are long lasting and effects on cell-mediated immune responses are still demonstrable 14 wk after the initial priming feed. We postulate that after an antigen feed in the neonatal period, immunologic and digestive immaturity lead to a net gain in T help which prevents the induction of systemic hyporesponsiveness (oral tolerance).

Aging↗
PubMed1984

Gluten intolerance (coeliac disease).

Coeliac disease is a permanent condition of gluten intolerance associated with characteristic gluten-sensitive changes in the jejunal mucosa. In Edinburgh and the Lothians Region of Scotland, the prevalence of the disease is one in 1637 (61/100,000) with considerable variation in age, and sex-specific prevalence and incidence. Several lines of evidence indicate an immunologic basis for the gluten-sensitive enteropathy in coeliac disease. Animal models of intestinal T cell-mediated reactions in the gut have shown pathologic features similar to those of coeliac disease. These include changes in villus and crypt architecture with crypt hyperplasia, and increased numbers of intraepithelial lymphocytes and of intraepithelial lymphocyte mitosis. Experimental CMI reactions also influence differentiation of goblet cells and expression of Ia antigen on epithelial cells, but these factors have not yet been reported for the coeliac mucosa. In addition to this circumstantial evidence, based on animal work, other factors which suggest that CMI reactions rather than antibodies are relevant to coeliac disease include the findings of antigliadin antibodies in a proportion of normal individuals, patients without gastrointestinal disease (seen in hospital), and patients with jejunal Crohn's disease. In addition, there is a well documented patient with adult onset primary hypogammaglobulinaemia and coeliac disease. The underlying pathogenesis in coeliac disease can be envisaged as failure of the normal inhibition of immune responses to this particular food antigen in the gut. Manipulation of immunoregulatory mechanisms would provide a new approach to treatment or cure of this disease and of other food protein-sensitive enteropathies.

Adult↗
PubMed1983

Changes in clinical features of coeliac disease in adults in Edinburgh and the Lothians 1960-79.

From 1960 to 1979 there was a threefold increase in the number of cases of coeliac disease diagnosed annually in adults in Edinburgh and the Lothians. Women accounted for 80% of the increase and their mean age at diagnosis was significantly reduced. The ratio of female to male new cases changed from 1.25 in the '60s to 2.5 in the '70s. In the period 1975-9 56 of 102 adults with coeliac disease presented with no gastrointestinal symptoms, including 30 cases diagnosed as a result of minor biochemical or haematological abnormalities, such as red-cell macrocytosis without anaemia. Over the same period, only 13 presented with a typical malabsorption syndrome compared to 24 of 38 (63%) in the years 1960-4. During 1975-9 58 new cases had no anaemia, compared with eight (21%) in the earlier period. Hypoproteinaemia (concentration less than 60 g/l) and hypocalcaemia of less than 2.00 mmol/l (8 mg/100 ml) were also less common. Though a real increase in the incidence of coeliac disease cannot be discounted, these changes are more likely to be the result of greater awareness of the disease and a lowered threshold for investigation.

Adolescent↗