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Biomedical subjects

S Gallagher

Publications and source records attributed to S Gallagher.

49 records · Page 3Linked to original sources
PubMed1984

Streak artefacts of the thoracic aorta: pseudodissection.

Streak artefacts running across images of the aorta can mimic aortic dissection on CT. We have compared 12 patients suffering from dissection with 45 others. Some artefacts were found in every patient. Such misleading appearances were more obtrusive in dissectors. However, we have found several pointers that help distinguish true intimal flaps from artefacts. Flaps are usually thin structures showing mild curvature. Artefacts are generally linear and vary in thickness. Their orientation may change markedly from one CT section to the next; they frequently extend beyond the confines of the aorta. In the ascending aorta, artefacts usually run at an angle of approximately 66 degrees to the coronal plane; especial care should be taken before diagnosing a straight intimal flap in that orientation. Careful study of images on the monitor rather than on film is a further help in the important distinction between artefact and intimal flap.

Aortic Dissection↗
PubMed1983

Ultrastructural and biochemical observations on the effect of 4-hydroxyanisole plus tyrosinase on normal human melanocytes and keratocytes in tissue culture.

Cultures of melanocytes and keratocytes were exposed to 15 micrograms ml-1 tyrosinase and 4-hydroxyanisole (4-OHA) 5 X 10(-4) M to 5 X 10(-2) M for 1 to 24 h. No damage was suffered by either cell below 5 X 10(-3) M 4-OHA for 6 h, but higher concentrations and longer exposures extensively damaged both cells. Exposure of cells washed free of culture medium to tyrosinase and 4-OHA 1 X 10(-3) M for 1 h resulted also in extensive damage. This indicates that an early-formed toxic product of the reaction between tyrosinase and 4-OHA is inactivated by constituents of the medium. This was confirmed by Liquid Chromatography and Scanning Spectrophotometry which showed that a toxic 4-OHA quinone immediately reacted with nucleophilic substances in the medium resulting in products which, on accumulation, are probably responsible for the later (6 h plus) damage to melanocytes and keratocytes. A possible effect of allegedly specific melanocytotoxic drugs on keratocytes should always be borne in mind with tissue culture experiments.

Anisoles↗
PubMed1983

Ultrasound has no anti-inflammatory effect.

The use of therapeutic ultrasound within the Health Service is widespread and growing. The most common indication is to reduce inflammation. We have tested the influence of ultrasound on a model of acute inflammation in the rat, and we have found a complete absence of any anti-inflammatory action.

Animals↗
PubMed1981

Mechanism of scorpion toxin-induced enzyme secretion in rat pancreas.

Scorpion venom induces acute pancreatitis in humans and stimulates pancreatic hypersecretion in several animal species. To clarify whether scorpion toxin influences pancreatic function directly by stimulating the acinar cells or influences pancreatic function indirectly by stimulating pancreatic nerves, we measured amylase release from both rat pancreas lobules (containing both acinar cells and nerves) and isolated rat pancreatic acini (acinar cells only). Scorpion toxin stimulated amylase release from lobules to a similar extent as did carbamylcholine, an acetylcholine agonist. In these lobules, the effect of scorpion toxin was blocked by both atropine (an inhibitor of the cholinergic receptor on acinar cells) and tetrodotoxin (a selective blocker of Na+ channels in nerves). In contrast, the effect of carbamylcholine was blocked by atropine, but not by tetrodotoxin. In isolated pancreatic acini, carbamylcholine was without effect. We conclude that scorpion toxin influences pancreatic function indirectly by stimulating the release of acetylcholine from pancreatic nerves.

Amylases↗
PubMed1980

Effect of azelaic acid on human malignant melanoma.

In 23 patients with malignant melanoma, including some with metastases and terminal patients, topical and oral (10--15 g daily) azelaic acid given for 1--12 weeks before surgical excision of the lesions was followed by arrest and subsequent regression of the advancing edge of lesions, reduction in size and flattening of nodular areas, and progressive lightening of pigmentation. Histological and ultrastructural effects included: degeneration and disappearance of malignant epidermal and dermal melanocytes with reduction of junctional activity; epidermal proliferation and return towards normal organisation; reappearance of papillary dermis, pilosebaceous units, and sweat glands; separation of dermal melanoma tumour masses into smaller collections of cells by regenerating connective tissue; and increase in number of dermal mast cells, macrophages, and round cells. These preliminary results indicate a direct cytotoxic effect of azelaic acid on melanocytes of human melanoma.

Administration, Oral↗
PubMed1976

Reticulum-cell sarcoma of the cervix.

Four patients with primary reticulum-cell sarcoma of the cervix were described. One patient was treated with radical hysterectomy and lymphadenectomy. The pelvic lymph nodes contained metastatic cancer and the patient died shortly after disseminating disease. The other three patients were treated with external radiation and vaginal and intrauterine radium application. The complete work-up failed to reveal cancer outside the pelvis or evidence of systemic disease. Two of these patients had an exploratory laparotomy with biopsies of pelvis and para-aortic lymph nodes and of the liver. One of these patients had a splenectomy, with no evidence of disease. Both patients are alive with no evidence of disease 3 and 10 years after their treatment. The third patient treated by radiation therapy died 2 years later with no evidence of disease. The importance of complete staging work-up and the advantage of radiation therapy in the treatment of reticulum-cell sarcoma of the cervix is emphasized.

Adult↗
PubMedDate not supplied

The effect of alginate on the invasion of cystic fibrosis respiratory epithelial cells by clinical isolates of Pseudomonas aeruginosa.

Chronic infection in the cystic fibrosis (CF) lung is characterized by Pseudomonas aeruginosa strains that overproduce the mucoid exopolysaccharide, alginate. Previous experiments have shown that long-term survival of P. aeruginosa in the CF lung may be facilitated by increased adherence and decreased invasion of respiratory epithelial cells. Therefore, mucoid and nonmucoid clinical isolates of P. aeruginosa were assayed for their ability to associate with and invade the CF respiratory epithelial cell line, CF/T43. Association assays and gentamicin exclusion assays demonstrated that mucoid P. aeruginosa associates with and invades CF/T43 cell monolayers significantly less than nonmucoid P. aeruginosa strains (P = .004, .02). Fluorescence microscopy invasion assays confirmed these results. The differences in association and invasion by the P. aeruginosa strains were not due to differences in lipopolysaccharide phenotype or cytotoxicity for CF/T43 respiratory epithelial cells. Exogenous bacterial alginate had no effect on the invasion of CF respiratory epithelia by a nonmucoid strain. Invasion assays with the wild-type P. aeruginosa strain PAO1 and isogenic algU and mucA mutant strains failed to show differences in invasion (P = .25). We conclude that (i) mucoid P. aeruginosa isolates associate with and invade CF/T43 respiratory epithelial cells with less efficiency than nonmucoid P. aeruginosa, (ii) these differences are not due to variations in lipopolysaccharide phenotype between strains, (iii) neither exogenous nor endogenous alginate affects the ability of P. aeruginosa to invade CF/T43 respiratory epithelial cells, and (iv) invasion of CF/T43 respiratory epithelial cells by a laboratory reference strain of P. aeruginosa does not appear to be regulated by AlgU.

Alginates↗
PubMedDate not supplied

Validity and reliability of sincerity test for dynamic trunk motions.

PURPOSE: Marras et al. developed a technique to evaluate sincerity of effort during dynamic trunk motion performance. The validity and reliability of the technique have not been evaluated. Therefore, the objective of this study was to first determine whether or not a sincerity of effort measure correctly identified those giving a sincere effort in a blinded randomized control trial and second to quantify inter-rater and test-retest reliability. METHODS: This article reports the findings of a two phase study. In phase one, the blinded evaluation, participants were randomly assigned to either a sincere or insincere performance condition. An examiner tested participants without knowledge of the participant's group membership. In the second phase, two examiners evaluated each participant twice to quantify inter-rater and test-retest reliability. RESULTS: In the blinded phase the specificity was 100% and sensitivity was 90% for identifying sincere and insincere effort, respectively. Phase two results showed no significant difference in probability of sincere effort between raters or between testing sessions. CONCLUSION: A performance criterion that accurately identifies sincere vs insincere group membership during functional evaluations was identified. There were no significant differences between raters or between testing sessions. These findings indicate that this test is reliable and possesses good predictive validity in assessing sincerity of effort.

Disability Evaluation↗