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Biomedical subjects

A Ferguson

Publications and source records attributed to A Ferguson.

At least 271 records · Page 15Linked to original sources
PubMed1981

Human intestinal mucosal mast cells: evaluation of fixation and staining techniques.

The staining properties of tissue mast cells are influenced by the method of fixation. Differences in fixation and staining techniques may explain the contradictory results in the published reports on the number of human mucosal mast cells (MMC) in the gastrointestinal mucosa in health and disease. We have examined the influence of fixatives on the staining properties of human MMC in operative biopsy specimens of human jejunum. Specimens were divided into pieces, each of which was fixed in one of the following fixatives: Carnoy's, basic lead acetate (BLA), Baker's, Bouin's, isotonic formol-acetic-acid (IFAA), 10% neutral buffered formalin, formol sublimate, and formol saline. Thereafter, tissues were paraffin-embedded and 5 micron sections were cut and stained with either astra-blue/safranin pH 0.3, or toluidine blue pH 0.5. Counts of the number of MMC/mm2 were obtained for each fixation method. The results show a critical influence of the fixative on the number of mast cells identified after staining. For example with astra-blue/safranin the mean MMC/mm2 count was 40 in formol-saline-fixed specimens, and 268 in Carnoy's-fixed specimens. In biopsies fixed with formalin-based fixatives, mast cells were more readily stained with toluidine blue. It is recommended that Carnoy's or BLA be used as the fixative for any light microscopic study of human MMC.

Cell Count↗
PubMed1981

Hypersensitivity in the small intestinal mucosa. V. Induction of cell-mediated immunity to a dietary antigen.

Feeding of a protein antigen to adult mice results in reduced humoral and cell-mediated immune (CMI) responses when that antigen is subsequently presented, and also causes activation of suppressor cells in the gut-associated lymphoid tissues (GALT). We have attempted to abrogate this tolerance to fed antigen by pretreating mice with 100 mg/kg cyclophosphamide before oral immunization and challenge with ovalbumin. Cyclophosphamide-pretreated mice did not develop serum haemagglutinating antibodies, nor systemic CMI (as assessed by skin testing) after ovalbumin feeding. However, evidence that CMI had been induced in the GALT was provided by the significant inhibition of migration and mesenteric lymph node cells from cyclophosphamide-pretreated animals, but not from other control groups. in the presence of ovalbumin. Our previous work on CMI reactions in the small intestine has shown that the cell production rate in the crypts of Lieberkuhn and the intraepithelial lymphocyte count are reliable although indirect measures of mucosal CMI. Cyclophosphamide-pretreated, ovalbumin-immunized animals, which had been fed 0 . 1 mg ovalbumin daily for 10 days before killing, had increased crypt cell mitoses, and increased intraepithelial lymphocyte counts, indicating the presence of mucosal CMI response to ovalbumin. Mechanisms whereby cyclophosphamide pretreatment leads to abrogation of tolerance and induction of mucosal CMI are discussed.

Animals↗
PubMed1981

Studies on hyperimmunoglobulinaemia E in atopic diseases with particular reference to food allergens.

Total and specific IgE have been measured in serum, suction blister fluid and jejunal aspirate in patients with various atopic disorders in an attempt to increase our knowledge of the association between food allergy and adult atopic eczema. We found (a) that patients with atopic disorders, irrespective of whether the disease affects primarily the skin or airways, have raised IgE concentrations that are largely attributable to antibodies directed against inhaled allergens; (b) that IgE antibodies against food allergens account for an appreciable amount of the total IgE in patients with atopic eczema though not as much as that contributed by inhalants; and (c) that in patients with atopic eczema, most of the IgE is produced at sites other than the intestine or skin.

Adolescent↗
PubMed1980

Neostigmine, pyridostigmine, and edrophonium as antagonists of pancuronium.

This study was performed to compare the effects of three anticholinesterases on rates of recovery from pancuronium-induced neuromuscular blockade. Pancuronium (3 mg/70 kg) was antagonized during nitrous oxide-oxygen-halothane anesthesia, in man, with neostigmine (2.5 or 5.0 mg/70 kg), pyridostigmine (10 or 20 mg/70 kg), or edrophonium (50 or 100 mg/70 kg). Reversal was attempted at 10 per cent spontaneous recovery of muscle twitch, which was measured by use of train-of-four stimulation. Following administration of the antagonists each patient had progressive recovery of neuromuscular function. Recurarization was not observed during the period of study. Recovery was most rapid with edrophonium and slowest with pyridostigmine. Five minutes after administration of the antagonists, mean T4, the height of the fourth twitch as a percentage of the first in each train, exceeded 50 per cent only with the larger dose of neostigmine and both doses of edrophonium. Thirty minutes after reversal there was no significant difference in recoveries among the drugs tested, and T4 exceeded 70 per cent for all patients. It is concluded that, under the conditions of this study, neostigmine, pyridostigmine, and edrophonium induce sustained antagonism of pancuronium-induced neuromuscular blockade. The antagonism produced by large doses of edrophonium is faster than that produced by neostigmine or pyridostigmine.

Adolescent↗
PubMed1980

Increased mucosal damage during parasite infection in mice fed an elemental diet.

We have examined the effects of parasite infection on the mucosal architecture of mice maintained on an elemental diet (Vivonex). Techniques used were conventional histology, micro-dissection and measurement of individual villi and crypts, and measurement of crypt cell proliferation rate by a metaphase accumulation technique. In normal, non-parasitised mice the elemental diet caused no change in villus height, crypt depth, or crypt cell proliferation. Likewise, the only effects of chronic protozoal infection or Nippostrongylus brasiliensis infection on the intestine of mice fed a normal diet have been a slight crypt hypertrophy and an increase in crypt cell proliferation rate without villous atrophy. However, the combination of elemental diet and parasite infection resulted in increased mucosal damage when compared with infected mice on a normal diet. Elemental diet mice infected with the nematode Nippostrongylus brasiliensis had significantly reduced villus height and correspondingly raised crypt length and metaphase accumulation rate. Elemental diet mice infected with the protozoan Giardia muris did not have villous atrophy but there was a significant increase in crypt length and metaphase accumulation when compared with infected normal diet mice. These experiments show that in two animal models of enteric infection, elemental diet has altered the host parasite relationship to the detriment of the host.

Animals↗
PubMed1979

Amniotic fluid optical density determination as a rapid test for assessment of fetal lung maturity.

The lecithin/sphingomyelin (L/S) ratios and optical densities at 650 nm were determined for 158 samples of amniotic fluid obtained by amniocentesis. A further 24 samples collected by vaginal aspiration from patients with spontaneous rupture of the membranes were also analysed. The relation between the L/S ratio and the optical density suggests that the more rapidly obtainable optical density measurement could be used as a screening procedure for fetal pulmonary maturity. A valid estimate of maturity by optical density is not possible in amniotic fluid aspirated from the vagina.

Amniocentesis↗
PubMed1979

Jejunal lysozyme activity and the Paneth cell in coeliac disease.

The jejunal mucosa of patients with coeliac disease contains significantly fewer Paneth cells (PCC) per crypt (p less than 0.001) and tissue lysozyme activity (JLA) P less than 0.001) when compared with a group of subjects with normal jejunal mucosa. Neither PCC nor JLA return to normal with complete clinical recovery and otherwise complete histological recovery on a gluten free diet. There is a significant linear correlation between JLA and PCC suggesting that the Paneth cell is the principal source of jejunal lysozyme.

Adult↗
PubMed1979

Effects of age, antigen deprivation, and allograft rejection on epithelial cell kinetics in mouse colon.

A technique of microdissection of colonic mucosa has allowed the study of mitotic activity, measured by metaphase accumulation following colchicine blockade, in individual crypts of mouse colon. The changes occurring during growth and development of normal colon have been studied and compared with changes found in antigen free colon (colonic isografts) and in cell-mediated immune damage of the bowel (allograft rejection). Metaphase accumulation was steady at two metaphases per hour in baby mouse colon until 18 days after birth. Between 18 and 24 days a rapid, and significant increase in mitotic activity occurred (P less than 0.01), reached adult values, and changed no further. Metaphase accumulation in isografts was similar to normal colon for the first two weeks after transplantation but the rise in mitotic activity in the third week did not occur. Allografts of colon showed two- to three-fold increases in metaphase accumulation when compared with both normal colon and isografts (P less than 0.01). When crypt mitotic activity was compared with the length of crypts measured in histological sections of normal colon, isografts, and allografts, no clear relationship was observed. Both changes in the luminal environment of the gut at the time of weaning and cell-mediated immune reactions in the colonic wall appeared to be associated with increased mitotic activity in colonic crypts.

Age Factors↗
PubMed1979

Small intestinal morphology and epithelial cell kinetics in lamb rotavirus infections.

Morphologic changes in the small intestine of rotavirus-infected gnotobiotic lambs were investigated by measurement of villi and crypts in histologic sections of jejunum, midgut, and posterior ileum. In midgut, villus atrophy developed within 12 hr of infection and was apparent until 72 hr after infection. Crypt hypertrophy was evident from 42 hr after infection until the end of the observation period (6 days after infection). Changes in posterior ileum were similar in extent, but jejunal changes were much less marked. The relatively mild effect in the jejunum is in accord with reports from other species, and provides a basis for questioning the assumption that human rotavirus affects mainly the foregut. Studies of epithelial cell kinetics were made on midgut using a microdissection and metaphase accumulation technique on sequential samples from anesthetized lambs. An increase in the cell production rate per crypt per hour from the overall control level of 5.8 was detected by 48 hr after infection. The maximum level of 21.2 was reached 8 days after infection, and this had returned to near normal by 15 days after infection. This large and sustained increase in crypt cell production probably underlies other previously described functional abnormalities.

Animals↗
PubMed1978

Primary biliary cirrhosis and coeliac disease: an association?

The association of primary biliary cirrhosis and coeliac disease, not previously reported, was observed in 4 patients. In each case, the two conditions were diagnosed simultaneously, and although symptoms were due to coeliac disease, initial investigation drew attention to the liver condition. All the patients responded to a gluten-free diet and remain well 2 years later. Primary biliary cirrhosis remains asymptomatic in 3 patients, but pruritus has developed in the 4th. The significance of this association is unclear and may merit formal study. Coeliac disease should be considered as a possible cause of unexplained weight loss in primary biliary cirrhosis.

Aged↗