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Biomedical subjects

M Brett

Publications and source records attributed to M Brett.

At least 37 records · Page 2Linked to original sources

Genomic fingerprinting of 80 strains from the WHO multicenter international typing study of listeria monocytogenes via pulsed-field gel electrophoresis (PFGE).

An international multicenter typing study of Listeria monocytogenes was initiated by the World Health Organization (Food Safety Unit, Geneva) in order to evaluate the usefulness of various phenotypic and genotypic typing methods for L. monocytogenes, to select and standardize the most appropriate methods to define common nomenclature of varieties and to select specific reference strains. Pulsed-field gel electrophoresis was used in four laboratories for molecular characterization of a set of 80 'coded' strains distributed to all participating laboratories. The endonucleases ApaI and SmaI, used in all four laboratories, yielded between 21 and 28 restriction endonuclease digestion profiles (REDP). AscI was used, in addition, in laboratory A and displayed 21 REDP. The combination of ApaI, SmaI or AscI REDP established 25 to 33 genomic groups. depending on the laboratory and the number of viable strains. Agreement of typing data among the four laboratories ranged from 79 to 90%. Forty-nine (69%) of the 71 strains viable in all four laboratories were placed into exactly the same genomic groups in all four laboratories. The epidemiological relevance of the strains became known after decoding and it was shown that most of the epidemiologically related strains were correctly identified by the four groups of investigators. i.e., most related strains were placed into the same genomic groups by all four laboratories. Similar results were obtained when 11 duplicate cultures were analyzed-on average 84% of the duplicates were identified. Comparison of REDP obtained by laboratory A with REDP from previously analyzed set of 176 L. monocytogenes strains allowed the prediction of the serovar-groups of the 80 strains. These predictions of serovar-groups were later confirmed by serotyping results obtained by laboratories involved in the WHO multicenter typing study of L. monocytogenes. In general this study reconfirmed that PFGE is a very accurate and reproducible method for fine structure comparison and molecular typing of L. monocytogenes.

Bacterial Typing Techniques↗

Operating department nurse education in Europe.

In October 1994 in Strasbourg the European Health Committee's Working party on the Role and Education of Nurses produced its draft revised version of the European 'Agreement on the Instruction and Education of Nurses'. It declared nursing to be both an art and a science that requires the understanding and application of knowledge and skills to provide the four main functions of nursing. Patient care, teaching, developing practice and acting as an expert in a multidisciplinary team are all common features expected of the operating department nurse. Just one week later at a joint meeting of the World Health Organisation (WHO) and European Chief Nurses, representing the 32 member states, Number 4 of the recommendations made by them for tackling current challenges was as follows: "Ensure that nurses and midwives have the basic and the post basic and continuing education they need to help them to become effective practitioners, teachers, managers, researchers and leaders and the opportunity to make appropriate use of their knowledge and skills" WHO & Chief Nurses, November 1994.

Clinical Competence↗

Classical conditioning in patients with Alzheimer's disease: a multiday study.

Previous studies demonstrated that patients with Alzheimer's disease (AD) do not acquire the classically conditioned eyeblink response. These studies, however, were only tested over a single conditioning session and, hence, raise the question of whether AD patients are capable of acquiring the response if sufficient training is given. This question may be of some importance whether AD patients can ultimately acquire the response has implications for the underlying neurobiological deficit in disrupted conditioning in AD. This study tested AD patients and age-matched controls over 4 days. As in previous studies, AD patients performed significantly worse than controls on Day 1, but by Day 4, they were not significantly different from controls. Subsequent testing indicated that these effects were not due to nonassociative variables such as changes in sensitivity to stimuli or disruption of the motor response. Also, it was reported that neither AD patients nor controls showed any evidence of acquisition in an explicitly unpaired paradigm, suggesting that neither pseudoconditioning nor sensitization is contributory. Data are discussed in terms of the possible role of the hippocampus in mediating conditioning deficits in AD patients.

Aged↗

Designing a common core curriculum for operating department nursing.

This paper has been written to outline the experiences of the European Operating Room Nurses Association in designing a Common Core Curriculum for European Operating Room Nursing. The process of curriculum planning is never one to be undertaken without an understanding of the complexity of producing what often appears as nothing more than a simple document once the task is completed. In most situations the planning of a curriculum is undertaken by a small team of people who prepare a structure and content which they themselves are actually going to implement, therefore the curriculum responds to the needs of the particular location for which it is intended. When a National Curriculum is developed it is usually done so by a group of people who work within the framework and guidelines of a national body, but they include local representatives from different areas to ensure that the finished product is one which can usefully be applied to all areas of the country. The designing of a curriculum for Europe brings a whole new dimension to curriculum planning.

Curriculum↗

Methicillin resistant Staphylococcus aureus (MRSA) in New Zealand 1988-90.

AIMS: To survey methicillin-resistant Staphylococcus aureus (MRSA) in New Zealand during the three years 1988-90. METHODS: Isolates and accompanying epidemiological data referred and reported to the New Zealand Communicable Disease Centre were analysed. RESULTS: MRSA was isolated from 255 persons, 235 patients and 20 healthcare staff, over the three years. The majority (84%) of persons were, or were recent, hospital patients or staff. Among hospital patients, males and patients aged 0 to 14 years were more likely to have MRSA. While most (88%) of the 145 strains identified occurred sporadically, three caused large outbreaks each involving more than 20 people. A third of the strains originated overseas, most commonly Australia or one of the Pacific Islands. The rate of MRSA isolation was higher in the North Island than the South Island. Two-thirds of the MRSA had only a low level of methicillin resistance and were not multiresistant. CONCLUSIONS: MRSA continues to be isolated only infrequently in New Zealand and has not become endemic in our hospitals.

Adolescent↗

Exercise-related potassium and free fatty acid level changes in coronary artery disease. Responses after moderate intensity training.

Exercise produces changes in circulating levels of potassium and free fatty acids which may provoke arrhythmias in patients with coronary artery disease. Twenty patients participating in 6 weeks of training were studied; 9 of these patients took part in 4 more weeks of training and a third exercise test. After 6 weeks, potassium levels were higher at submaximal levels of exercise, free fatty acid levels were reduced at rest, and at 5, 15, and at 30 min post-exercise. Norepinephrine levels were reduced at submaximal work loads after 6 weeks and increased at maximal work loads. The extra 4 weeks had no additive effect on these metabolic changes. Participation by coronary artery disease patients in a short-term, moderate intensity, exercise training program increases potassium levels at submaximal work loads and reduces levels of free fatty acids at rest and after exercise. The arrhythmogenic relevance of these findings deserves further consideration.

Aged↗

Treatment of recurrent urethral strictures using clean intermittent self-catheterisation.

The treatment of urethral strictures has been greatly improved by the use of the optical urethrotome. However, there remains a group of patients with recurrent strictures for whom the alternatives remain long-term dilatation/urethrotomy or urethroplasty. Over the last 3 years we have treated 65 such patients using clean intermittent self-catheterisation as a method of self-dilatation. This has resulted in a dramatic decrease in the number of operations performed on these patients, with no significant reduction in urinary flow rate over an average follow-up period of 20 months. The method offers the possibility of long-term cure and should be offered to all all such patients, reducing still further the number of patients who require urethroplasty.

Adolescent↗

The structure of mammalian rod opsins.

Ovine rhodopsin is organised in disc membranes as a monomer. The determination of its amino acid sequence has permitted the utilisation of structure prediction programmes which indicate the probable disposition of the polypeptide chain in the bilayer. This putative model is consistent with labelling data using the chemical probes, [14C]succinic anhydride, [125I]diazodiido sulphanilic acid and [125I]iodophenyl azide, and with the cleavage points for several proteases. More surprisingly the predicted structure points to the occurrence of breaks/distortions in the transmembrane helical segments. These distorted regions may be of primary functional importance to the protein and at least one is associated with the attachment point of the chromophore. This particular part of the structure is also identified as a "mutational hot spot", for bovine, equine, ovine and porcine opsins exhibit different sequences (but conserved molecular volumes) in the four residues following the retinyllysine. In an otherwise highly conserved protein with no obvious functional differences between the four species, the high substitution rate in this region is unexplained.

Amino Acid Sequence↗

Isolation and characterization of the CNBr peptides from the proteolytically derived N-terminal fragment of ovine opsin.

Ovine rhodopsin may be cleaved in situ by Staphylococcus aureus V8 proteinase into two membrane-bound fragments designated V8-L (27 000 mol.wt.) and V8-S (12 000 mol.wt.). After purification of the proteolysed complex by affinity chromatography in detergent using concanavalin A immobilized on Sepharose 4B, the two polypeptide fragments may be separated by gel-permeation chromatography on Sephadex LH-60. Digestion of the N-terminal-derived V8-L fragment with CNBr in 70% (v/v) trifluoroacetic acid resulted in a peptide mixture that could be fractionated by procedures involving gel-permeation chromatography in organic and aqueous solvents and the use of differential solubility. The complete or partial sequences of all ten peptides are reported.

Amino Acid Sequence↗

Investigation of the organization of rhodopsin in the sheep photoreceptor membrane by using cross-linking reagents.

The organization of rhodopsin in the photoreceptor membrane of sheep rod outer segments was investigated by using a variety of bifunctional reagents. Of the nine reagents used, seven gave oligomeric opsin species, whereas two, copper phenanthroline and dithiobisphenyl azide, failed to cross-link the protein. In general, the cross-linked species obtained showed diminishing yields from dimer to tetramer, together with some higher-molecular-weight aggregates. It is proposed that the patterns of cross-linking arise as a result of collision complexes and best describe a monomeric organization for native rhodopsin. No significant differences between the patterns obtained with dark-adapted bleached or regenerated protein states were observed. This interpretation is discussed in relation to the postulated mechanism of action of rhodopsin.

Animals↗

Amino acid replacements resulting from suppression and missense reversion of a chain-terminator mutation in Neurospora.

The Neurospora crassa super-suppressor mutation, ssu-1, suppresses the auxotrophic phenotype of the mutant am(17) by inserting tyrosine at residue 313 of NADP-specific glutamate dehydrogenase, a position occupied in the wild type by glutamate. Two classes of am(17) revertants due to further mutation within the am gene have, respectively, tyrosine and leucine at residue 313. These replacements are consistent with a chain-terminating codon in am(17) of either the amber (UAG) or the ochre type (UAA), but are inconsistent with UGA. The Leu313 and Tyr313 variants of the enzyme have effective activity but are grossly different from the wild type in Michaelis constants (especially for ammonium) and heat stabilities at two different pH values. They show smaller but significant differences in these respects from each other.

Amino Acid Sequence↗