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Biomedical subjects

M Paton

Publications and source records attributed to M Paton.

7 recordsLinked to original sources
PubMed2000

Aldehyde oxidase is coamplified with the World's most common Culex mosquito insecticide resistance-associated esterases.

The evolution and spread of insecticide resistance is an important factor in human disease prevention and crop protection. The mosquito Culex quinquefasciatus is the main vector of the disease filariasis and a member of a species complex which is a common biting nuisance worldwide. The common insecticide resistance mechanism in this species involves germline amplification of the esterases estalpha21 and estbeta21. This amplification has arisen once and rapidly spread worldwide. Less common and more variable resistance phenotypes involve coamplification of estalpha3 and estbeta1, or individual amplification of a single estbeta1, different alleles of the same estalpha and estbeta gene loci. Estalpha21 and estbeta21 are on the same large fragment of amplified DNA (amplicon) 2.7 kb apart. We have now shown that this amplicon contains another full-length gene immediately 5' of estalpha21 which codes for a molybdenum-containing hydroxylase, with highest homology to aldehyde oxidase (AO) from other organisms. The full-length putative AO gene is not present on the estalpha3/estbeta1 or estbeta1 amplicons, but multiple truncated 5' ends of this gene are present around the presumed estalpha3/estbeta1 amplicon breakpoint. Polymerase chain reaction (PCR) analysis of insecticide-susceptible genomic DNA demonstrated that a different allele of the putative AO gene in its non-amplified form is immediately 5' of estalpha. The 'AO' gene on the estalpha21/estbeta21 amplicon is expressed and resistant insects have greater AO activity. This AO activity is sensitive to inhibition by an aldehyde-containing herbicide and pesticide. This enzyme may confer a selective advantage to these insects in the presence of insecticide, as AO in mammals is believed to be important in the detoxification process of several environmental pollutants.

Aldehyde Oxidase↗
PubMed1997

Three dimensional imaging of the Belousov-Zhabotinsky reaction using magnetic resonance.

The combination of 3D magnetic resonance imaging data with polygon based computer graphic display software is ideally suited to the study of the Belousov-Zhabotinsky reaction in extended volumes. In this paper we present the first true three dimensional visualization of experimental data from the Belousov-Zhabotinsky reaction. The time evolution of a twisted scroll wave like isoconcentration surface and its organizing filament are demonstrated for the manganese-catalyzed B-Z mixture. These techniques extend the experimental study of the B-Z reaction as a class of pattern-forming systems to the third dimension. The limitations of the technique are discussed.

Computer Simulation↗
PubMed1987

Evaluation of an enzyme-linked immunosorbent assay for the detection of Corynebacterium pseudotuberculosis infection in sheep.

Two enzyme-linked immunosorbent assays to measure antibody to the cell wall antigen (C-ELISA) and toxin antigen (T-ELISA) of C. pseudotuberculosis were evaluated on serum from 6 separate groups of sheep. For sheep naturally infected with C. pseudotuberculosis the sensitivity and specificity of the C-ELISA was 76% and 73% respectively and for the T-ELISA 67% and 77% respectively. For sheep slaughtered one year after artificial infection the sensitivity of both tests was greater than or equal to 83% and the specificity greater than or equal to 72%. For sheep slaughtered 4 months after artificial infection the specificity of both tests was less than 30% while the mean sensitivity was 85%. The C-ELISA in conjunction with the T-ELISA detected 92% of sheep with lung lesions.

Animals↗
PubMedDate not supplied

Intracellular killing of Candida albicans by human neutrophils is potentiated by exposure to combinations of amphotericin B and 5-fluorocytosine.

Combination treatment with amphotericin B and 5-fluorocytosine is synergistic and has become clinically useful in the treatment of various forms of systemic candidosis. The synergy between these two compounds may be explained in part by their combined effect on the interaction between fungal cells and host phagocytes. Pretreatment of Candida albicans for 2 h with either amphotericin B or 5-fluorocytosine or the two agents in combination did not inhibit or enhance phagocytosis by glass-adherent human neutrophils (P greater than 0.05). Intracellular killing of pretreated yeast cells was not influenced by antifungals alone (P greater than 0.05), but pretreatment of C. albicans with 5.0 mg l-1 amphotericin B + 10 l-1 5-fluorocytosine or 5.0 mg l-1 amphotericin B + 50 mg l-1 5-fluorocytosine significantly enhanced the ability of neutrophils to kill the number of viable yeast cells intracellularly (P less than 0.001).

Amphotericin B↗
PubMedDate not supplied

Further evidence of functional differentiation within biceps brachii.

This study investigated whether the two heads of Biceps Brachii could be functionally differentiated during rapid supination movements with different degrees of elbow flexion, shoulder axial rotation and load. Surface electromyograms, recorded from the long and short heads of Biceps Brachii, were utilised to identify changes in the intensity of muscle contraction. Based upon an analysis of sixteen subjects, the results indicated that joint position (muscle length), but not load, significantly (p < 0.05) influenced the relationship between the contraction intensities of the two heads. Specifically, increasing the length of the Biceps Brachii promoted increased activation of the long head in relation to the short head in producing rapid supination motions. It was concluded that functional differentiation within the two heads of Biceps Brachii was present in motions involving its distal insertion.

Adolescent↗