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Biomedical subjects

M Logan

Publications and source records attributed to M Logan.

At least 55 records · Page 3Linked to original sources
PubMed1994

Breathing systems: effect of fresh gas flow rate on enflurane consumption.

The vaporization rates of enflurane were measured in 412 anaesthetics using appropriate fresh gas flow rates in Bain (12 litre min-1), Magill (6 litre min-1) and circle systems (3 litre min-1, 1 litre min-1 and "closed"). In all patients reducing the fresh gas flow rate resulted in lower enflurane consumption. The percent savings were 18-86% depending on the initial fresh gas flow rate and the size of the change in fresh gas flow. The reduction in enflurane use was more marked in inpatients (long cases) than in day-case patients (short cases).

Anesthesia, Inhalation↗
PubMed1993

Multiple copies of genes coding for electron transport proteins in the bacterium Nitrosomonas europaea.

The genome of Nitrosomonas europaea contains at least three copies each of the genes coding for hydroxylamine oxidoreductase (HAO) and cytochrome c554. A copy of an HAO gene is always located within 2.7 kb of a copy of a cytochrome c554 gene. Cytochrome P-460, a protein that shares very unusual spectral features with HAO, was found to be encoded by a gene separate from the HAO genes.

Amino Acid Sequence↗
PubMed1993

Induction of cardiac muscle differentiation in isolated animal pole explants of Xenopus laevis embryos.

We have isolated a cDNA fragment encoding a portion of the myosin heavy chain alpha-isoform (XMHC alpha) in the amphibian, Xenopus laevis. The XMHC alpha transcript is highly enriched in adult heart RNA and is expressed exclusively in embryonic heart tissue. It therefore provides a tissue-specific marker for cardiac muscle differentiation during early embryogenesis. Using an RNAase protection assay, we can detect the onset of cardiac muscle differentiation in an anterior, ventral region of tailbud embryos, many hours before the appearance of a beating heart. Whole-mount in situ RNA hybridisation indicates that expression of the XMHC alpha gene is restricted to the developing heart primordium. XMHC alpha gene expression can also be induced in isolated animal pole explants of blastulae by treatment with the growth factor, activin A. Induction is dose-dependent, requiring high doses of the growth factor compared with that required for myotomal (skeletal) muscle differentiation. In contrast, no XMHC alpha transcripts are detected in explants incubated with basic FGF, despite the induction of myotomal muscle differentiation. Activin-induced explants show a similar temporal pattern of XMHC alpha gene expression to that found in normal embryogenesis. Furthermore, cells expressing this gene appear clustered in one or two foci within fused explant aggregates, which often show regular, spontaneous contractions after several days in culture. These results show that terminal differentiation of cardiac muscle can occur in growth factor-induced explants and may be distinguished from skeletal muscle differentiation by the dose and nature of the inducing factor.

Activins↗
PubMed1993

The cloning and expression of the gene for ovine interleukin-3 (multi-CSF) and a comparison of the in vitro hematopoietic activity of ovine IL-3 with ovine GM-CSF and human M-CSF.

The ovine interleukin-3 (IL-3) gene has been cloned. It encodes a protein 146 amino acids (aa) in length and is situated approximately 10 kb from the gene encoding granulocyte-macrophage colony-stimulating factor (GM-CSF). A comparison of the ovine gene sequence with that of the human IL-3 gene reveals that the protein coding regions share between 49 and 59% identity, while the introns and other noncoding regions share between 63 and 78% identity. The gene promoters also share approximately 72% identity. Recombinant ovine IL-3 (rovIL-3) was expressed in Chinese hamster ovary (CHO) cells, and its biologic activity was compared to that of rovGM-CSF and recombinant human macrophage colony-stimulating factor (rhM-CSF) on ovine bone marrow cells. rovIL-3 predominantly stimulated the growth and development of mast cells and macrophages in liquid cultures and colonies of mixed cell phenotype, megakaryocytes, erythroid burst-forming units (BFU-E), and basophilic granular cells in soft agar cultures of bone marrow cells. In common with rovGM-CSF, IL-3 also stimulated eosinophil and macrophage colonies, which were increased in size and number of cells in cultures containing both cytokines. Maximum macrophage colony numbers were achieved with the combination of rovIL-3, rovGM-CSF, and rhM-CSF. rovGM-CSF stimulated neutrophil colony formation, whereas rovIL-3 did not.

Amino Acid Sequence↗
PubMed1991

Production of interferons by bovine and ovine cell lines infected with Theileria annulata or Theileria parva.

Three bovine cell lines and four ovine cell lines infected with Theileria parva or Theileria annulata were examined for the production of interferon (IFN). Biologically active IFN was detected in the tissue culture supernatants of four of the cell lines. Only one, a bovine cell line infected with T. parva, produced IFN-gamma as measured by specific neutralization with a monoclonal antibody to bovine IFN-gamma. This observation was confirmed by analysing RNA from the cell lines on Northern blots using an IFN-gamma cDNA probe. The other three cell lines which produced IFN were infected with T. annulata. The IFN produced by those lines was not IFN-gamma.

Animals↗
PubMed1991

Pharmacokinetics and tissue penetration of tazobactam administered alone and with piperacillin.

The pharmacokinetics of tazobactam (500 mg) administered intravenously alone were compared with the pharmacokinetics of tazobactam coadministered with piperacillin (4 g), and the penetration into an inflammatory exudate in six healthy males was studied. Piperacillin influenced the pharmacokinetics of tazobactam. The mean levels of tazobactam in plasma at 4 h were 0.6 microgram/ml when it was given alone and 1.2 micrograms/ml when it was given with piperacillin (P = 0.0003). The mean total clearances of tazobactam were 203.5 and 134.2 ml/min (P = 0.035) when it was given alone and with piperacillin, respectively There were no significant differences in the elimination half lives, areas under the concentration-time curve from 0 h to infinity, or volumes of distribution. Inflammatory exudate penetration was rapid, and the mean maximum levels of tazobactam attained were 6.4 and 11.3 micrograms/ml when it was given alone or with piperacillin, respectively (P less than 0.06). The mean percent penetration of tazobactam and the area under the concentration-time curve from 0 h to infinity in inflammatory exudate were greater when tazobactam was given with piperacillin. The mean 24-h urinary recoveries of tazobactam were 63.7% +/- 7.9% when it was given alone and 56.8% +/- 2.7% when it was given with piperacillin. The explanation for the differences in the pharmacokinetics of tazobactam when it was administered alone compared with those when it was given with piperacillin was unclear.

Adult↗
PubMed1990

Implementing the Roy model: challenges for nurse educators.

The experience of selecting and implementing a nursing model appropriate to the nursing course in the first year of the generic baccalaureate programme of the University of Ottawa School of Nursing is described. Many challenges surfaced for the professors in year one as this curriculum change was implemented. Four challenges: (1) adapting the course to be congruent with the Roy model, (2) developing teaching tools suitable for student learning, (3) sequencing of content for student learning, and (4) obtaining competent role models, and how they were met, are discussed.

Adaptation, Psychological↗
PubMed1990

The Roy Adaptation Model: are nursing diagnoses amenable to independent nurse functions?

In this article, current knowledge of nursing diagnosis is compared to the assumptions of the Roy Adaptation Model for Nursing. More specifically the relationship between the aetiology component of diagnostic statements and stimuli is explored. Examples of nursing diagnoses from the literature are also presented to analyse the relationship between aetiologies and independent nurse functions.

Adaptation, Psychological↗
PubMed1990

Meropenem pharmacokinetics and penetration into an inflammatory exudate.

The pharmacokinetics and penetration into a cantharidine-induced inflammatory exudate of meropenem was studied in six volunteers following a single 1-g intravenous dose. Concentrations in plasma, urine, and the inflammatory exudate were determined by a microbiological assay. The mean elimination half-life of meropenem in plasma was 1.1 h, with the concentration in plasma declining from a mean of 23.6 micrograms/ml at 1 h to 0.7 micrograms/ml at 6 h. The inflammatory fluid penetration was rapid (time to maximum concentration of drug in serum, 0.75 h), and the penetration was 111%. The recovery of meropenem in urine at 24 h was 65.4% of the administered dose.

Adult↗
PubMed1990

Degradation of halogenated aliphatic compounds by the ammonia- oxidizing bacterium Nitrosomonas europaea.

Suspensions of Nitrosomonas europaea catalyzed the ammonia-stimulated aerobic transformation of the halogenated aliphatic compounds dichloromethane, dibromomethane, trichloromethane (chloroform), bromoethane, 1,2-dibromoethane (ethylene dibromide), 1,1,2-trichloroethane, 1,1,1-trichloroethane, monochloroethylene (vinyl chloride), gem-dichloroethylene, cis- and trans-dichloroethylene, cis-dibromoethylene, trichloroethylene, and 1,2,3-trichloropropane, Tetrachloromethane (carbon tetrachloride), tetrachloroethylene (perchloroethylene), and trans-dibromoethylene were not degraded.

Ammonia↗
PubMed1990

The management of hydrothorax in continuous ambulatory peritoneal dialysis (CAPD).

Four patients on continuous ambulatory peritoneal dialysis (CAPD) developed large, symptomatic pleural effusions after commencing peritoneal dialysis. Pleuroperitoneal fistula in each case was diagnosed by the presence of a high glucose content in pleural fluid, with a normal corresponding blood sugar, and was confirmed by isotope or contrast peritoneography. Two patients had their effusions drained percutaneously, and then underwent pleural sclerosis with intracavitary tetracycline. Two patients had a thoracotomy performed, of which no fistula was identified in one case, and the other patient underwent pleurectomy. All four patients successfully recommenced CAPD several weeks after therapy, without recurrence of effusions. We conclude that pleuroperitoneal connections associated with CAPD do not mandate cessation of peritoneal dialysis and conversion to maintenance haemodialysis. Definitive diagnosis requires aspiration of pleural effusions for glucose estimation. Contrast or isotopic peritoneography is helpful in localising the fistula, but in our experience did not alter management. Simple sclerotherapy is effective and avoids the need for a formal thoracotomy.

Aged↗