Biomedical subjects
Publications and source records attributed to Christopher Johns.
One hundred diatom species have been selected for genome and transcriptome sequencing. The 100 Diatom Genomes Project aims to provide a scalable framework for understanding diatom biodiversity, ecology and evolution, and for investigating their use in biotechnology.
In this study, we investigated the effects of histone deacetylase (HDAC) inhibitors suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA) on the metabolism of polycyclic aromatic hydrocarbons (PAH) in human mammary carcinoma derived MCF-7 cells in culture. Benzo[a]pyrene (B[a]P) induces cytochrome P450 (CYP) 1A1, CYP1B1 and other xenobiotic metabolizing enzymes. Results from our study indicated a significant increase in CYP activity in comparison to vehicle control in cells treated with SAHA or TSA as measured by ethoxyresorufin-O-deethylase assay. However, co-treatment with 1.0 microM SAHA and BP, reduced the mRNA levels of CYP1B1 relative to B[a]P alone. When co-treated with 1.0 microM TSA and BP, a reduction in the mRNA levels of both CYP1A1 and CYP1B1 was observed relative to BP alone. We further investigated to ascertain if the differential expression and activity of CYP1A1 and CYP1B1 influenced levels of B[a]P DNA adduct formation. MCF-7 cells co-treated with B[a]P and SAHA or TSA formed DNA adducts, although no significant differences in levels of DNA binding were revealed. These results suggest that while CYP enzyme activity and gene expression were affected by the HDAC inhibitors SAHA and TSA, they had no apparent influence on B[a]P DNA binding.
Reflection is always purposeful toward realising expert practice. Yet how might expertise be recognised? Using a narrative approach, Benner, Tanner and Chesta (Expertise in nursing practice. Springer Publishing, New York, 1996) explicated a model of expertise that offers the practitioner a useful framework to reflect on their expertise which I do using my own narrative of dwelling with Alison, given that expert practice must be the concern of every practitioner.
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A single nucleotide polymorphism (TNF(-308A)) within the promoter region of the gene encoding tumor necrosis factor (TNF), has been significantly associated with schizophrenia in a study of Italian patients and control subjects Boin et al. [2001: Mol Psychiatry 6:79-82]. We have applied case-control analyses to examine TNF promoter haplotypes (containing TNF(-308) and two additional promoter variants: TNF(-376) and TNF(-238)) in four schizophrenia cohorts drawn from Australian, Indian Fijian, Indigenous Fijian, and Brahmin populations. In addition, we have applied the sibling transmission disequilibrium (STD) test to promoter haplotypes within 81 trios drawn from Australian Caucasian pedigrees with multiple schizophrenia cases, and 86 trios drawn from the Brahmin population of Tamil Nadu province in Southern India. Within each of these cohorts, we found no evidence of recombination between these tightly linked promoter variants, supporting previous studies which demonstrated that only a subset of the eight possible haplotypes exist. Of the four observed haplotypes, we and others have observed only one carries the TNF(-308A) variant allele. We report no significant differences in TNF promoter haplotype frequencies between the patient and control groups within each population, although the Indian Fijian cohort showed a trend towards reduced TNF(-308A) alleles amongst schizophrenia cases (P = 0.07). We found no evidence of bias in TNF promoter haplotype transmission to schizophrenia probands. Very similar results were obtained when only the TNF(-308) polymorphism was considered. Taken together, these data provide no support for the involvement of TNF promoter variants TNF(-308), TNF(-376), and TNF(-238) in schizophrenia susceptibility within four ethnically distinct cohorts.
As a reflective practitioner I write a journal, reflecting on significant experiences through the day. In this paper, I present a day in my life as a part-time nurse and complementary therapist at the hospice where I work. In particular, I focus my reflection on my ability and value of dwelling with patients as a clearing to enhance my therapeutic work.
Clinical leadership and clinical supervision are topical areas of nursing development. A project was established to facilitate the growth of leadership ability with a group of ward sisters through individual clinical supervision. The work revealed that ward managers struggled to fulfil their leadership roles largely because of embodied ways of relating within a prevailing organizational culture that constrained them. The paper also reflects on the impact of supervision to develop leadership practice.
Being attached to a piece of medical technology may cause patients physical and emotional distress. Critical care nurses need to empathize and respond to the patient's experience on being attached to all forms of medical equipment. The use of sedation must be carefully considered in response to agitation. Critical care is also palliative care. Compassion is a virtue.