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Biomedical subjects

S Morrissey

Publications and source records attributed to S Morrissey.

10 recordsLinked to original sources
PubMed1991

Blood transfusion and laryngeal cancer.

Evidence exists to suggest a detrimental effect of blood transfusion on survival after resection for malignant disease. Immune suppression due to transfusion has been implicated, though this remains unproven. We have conducted a retrospective study of 69 patients (38 transfused, 31 not transfused) with squamous carcinoma of the larynx to assess the effect of blood transfusion on survival after laryngectomy. Patients were compared for age, sex, smoking habit, tumour site and stage, grade of operating surgeon, preoperative haemoglobin, tumour nucleolar organizer region status, and operation time. The minimum follow-up was 5 years. In the transfused group 21/38 died as a result of their malignant disease and only 4/31 in the untransfused group. This difference was highly significant (P less than 0.001, chi-squared test) and using a multivariate analysis the only variable associated with a decreased survival time was whether a blood transfusion had been received. We conclude that peri-operative blood transfusion is associated with decreased survival after laryngectomy. However, whether this association is causal remains unproven.

Aged↗
PubMed1988

Plasmids in bacteria exposed to activated neutrophils mediate mutagenesis when transferred to new hosts.

The plasmid pUC18 contains a lacZ alpha-complementation gene that codes for a small peptide that can complement the delta M15 mutation of the Escherichia coli lacZ (beta-galactosidase) gene, converting bacteria carrying that mutated gene from the lacZ- to the lacZ+ phenotype. This plasmid was used in experiments designed to study mutagenesis by human neutrophils. E coli carrying pUC18 were incubated with neutrophils under conditions in which little ingestion of the bacteria took place; the plasmid was then isolated and transformed into an E coli strain (BOZO) that carries the lacZ delta M15 mutation. Of these transformants, 11 of 205,000 were lacZ, suggesting that in these 11, alpha-complementation had been lost through a mutation. No lac- colonies were detected among several hundred thousand BOZO transformed with plasmid isolated from incubations in which phagocytosis could take place, nor from incubations from which neutrophils were omitted. Despite the lac- phenotype of these 11 transformants, plasmids reisolated from nine of them showed normal alpha-complementing ability when transformed into fresh BOZO. These findings indicated that in these nine, the mutations were located in the chromosomes of the transformed BOZO. It thus appears that on exposure to activated neutrophils, a plasmid may acquire a lesion (? mutation) that can somehow be transferred to the genome of a recipient microorganism, resulting in repair of the damaged plasmid accompanied by mutation of the recipient's chromosome. Restriction mapping of the DNA from four of these nine chromosomal mutants suggested that the mutations did not represent major insertions or deletions in the portion of the bacterial chromosome corresponding to the pUC18 lac operon insert, nor in the remainder of the lacZ delta M15 gene. These results confirm previous work showing that exposure to activated neutrophils can induce mutations in biological systems, and provides an experimental model in which the mechanism of neutrophil-mediated mutagenesis may be examined.

Blood Bactericidal Activity↗
PubMed1986

Does the purity of intraportal islet isografts affect their endocrine function?

The effect of collagenase digested pancreatic tissue upon the endocrine function of intraportal islet isografts has been studied in rats. The ability of transplanted islets to restore normoglycemia in recipients was not affected by tissue contamination, but the insulin response to glucose challenge 12 weeks after transplantation was negatively correlated with the amylase content of this additional tissue transplant. All animals receiving a single dispersed pancreas died within 24 hr. These findings are discussed in relation to transplantation of the dispersed pancreas in human.

Animals↗
PubMed1986

A new tetracycline-resistance determinant, class E, isolated from Enterobacteriaceae.

A fifth tetracycline(Tc)-resistance determinant, designated class E, has been identified on a transferable plasmid found in a fecal strain of Escherichia coli. This determinant does not show homology by DNA-DNA hybridization at high stringency with any of four other Tc resistance determinants (classes A, B, C and D) previously described among the Enterobacteriaceae. Resistance is inducible by 1 microgram Tc/ml and increases the minimum inhibitory concentration 130-fold for Tc and 3.5-fold for minocycline. The mechanism, like that of the other four determinants examined, appears to involve an active efflux of the drug. Using a 32P-labeled cloned fragment containing the resistance determinant, we have found the determinant in Aeromonas, but not in any of over 200 other E. coli strains tested.

Aeromonas↗