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Biomedical subjects

F Allan

Publications and source records attributed to F Allan.

9 recordsLinked to original sources
PubMed1982

Impaired antibody-dependent cell-mediated cytotoxicity in cryptogenic fibrosing alveolitis (synonym: idiopathic pulmonary fibrosis).

Mononuclear cells from the blood of 26 patients with the 'autoimmune' connective tissue disorder cryptogenic fibrosing alveolitis (CFA) were examined in Chang cell cytotoxicity assays for their capacity to mediate antibody-dependent cell-mediated cytotoxicity (ADCC). The results showed an impairment for the group by comparison with a group of 45 normal healthy controls (P less than 0.01). The impairment was greater in patients with associated connective tissue disorders of other systems (CFA+CT) than in those having the lung disorder alone (lone CFA); (P less than 0.001). The reduction in ADCC showed a correlation with reducing counts of cells bearing Fc gamma G surface receptors (P less than 0.05), and with increasing levels of soluble immune complexes in the blood of these patients by C1q binding (P=0.05). Non-specific esterase staining indicated that the Fc gamma G rosetting cells were subpopulations of lymphocytes not monocytes. We therefore suggest that the observed ADCC impairment may be due to impairment of lymphocyte Fc receptor function, and we speculate that this may influence immune regulation.

Adult↗
PubMed1981

Diarrhea in lambs experimentally infected with Cryptosporidium isolated from calves.

Two to 5 days after oral inoculation with Cryptosporidium obtained from infected calves, 7 newborn specific-pathogen-free lambs became depressed and anorectic and developed diarrhea. Four moribund lambs were killed within 3 days after onset of illness, and the 3 other lambs died after protracted intermittent diarrhea and reduced milk intake, which lasted up to 14 days. The small and large intestines were heavily infected with Cryptosporidium, with the terminal portion of the ileum being the most severely affected. Histologic examination revealed villous atrophy, with considerable fusion and epithelial cross-bridging between villi. Lambs infected at 5 to 20 days of age had less severe clinical signs of disease, with intermittent diarrhea, reduced milk intake, and growth retardation. Lambs infected at 30 days of age became infected with the organism, but did not develop clinical signs of disease or growth retardation.

Animals↗
PubMed1980

Environmental factors in allergic bronchopulmonary aspergillosis.

Many workers have suggested that exposure to an environment rich in Aspergillus spores is aetiologically significant in allergic bronchopulmonary aspergillosis. This hypothesis has been investigated by means of an environmental survey in which eight urban dwelling patients with this disease and five atopic control patients took part. Enquiries were made about contact with known sources of Aspergillus fumigatus and air spora studies were conducted in the home. Findings were similar for both groups. No high spore concentrations were recorded in the homes of either group. Patients with allergic bronchopulmonary aspergillosis had not been more exposed to potentially rich sources of A. fumigatus than the atopic control patients. The view is expressed that specific host susceptibility is more important in the pathogenesis of allergic bronchopulmonary aspergillosis than environmental factors. Ince a patient is sensitized however minor increases in spore concentration can cause symptomatic disease producing the recognized winter exacerbations of allergic bronchopulmonary aspergillosis. Possible mechanisms allowing the development of the disease in the presence of low spore concentrations are discussed.

Adolescent↗
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↗
PubMed1977

Technique for microdissection and measurement in biopsies of human small intestine.

A microdissection and measurement technique has been adapted for biopsy of human small intestine. Specimens fixed in alcohol and acetic acid are Schiff stained in bulk. Villi and crypts are then dissected out under a dissecting microscope, placed under a coverslip, examined, measured, and the number of mitoses in individual crypts counted. With this method specimens of normal small intestine have been found to have villi 500 microns to 1100 microns long and crypts 150 microns to 300 microns. These values were double those obtained when measuring sections of the same specimens stained with haematoxylin and eosin. The mean number of mitoses per crypt in normal duodenum and jejunum ranged from 1 to 12 and most of the cells in mitosis were in prophase or telophase. This rapid, sensitive, and inexpensive technique complements the available methods of measuring small intestinal architecture.

Biopsy↗