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Biomedical subjects

A Sadler

Publications and source records attributed to A Sadler.

12 recordsLinked to original sources
PubMed1996

Personality and stress in consultant psychiatrists.

A randomly selected group of consultant psychiatrists (n = 39) working within the NHS in Scotland was compared with a combined group of physicians and surgeons (n = 149) on several variables related to the stress process, including personality traits, coping strategies, psychological distress, burnout, job stress and work demands. Psychiatrists reported fewer clinical work demands (p < .001), and their mean personality scores were significantly different from physicians and surgeons by being high in neuroticism (p = .009), openness (p = .003) and agreeableness (p = .002), and low in conscientiousness (p = .04). Psychiatrists reported higher work-related emotional exhaustion (p = .03) and severe depression (p = .02). However, psychiatrists did not report more work-related stress than physicians and surgeons. Many stress-related variables were highly correlated within the group of psychiatrists, suggesting that there is a very general disposition to experience negative emotion (including job-related stress) in some individuals. Organisational and personal contributions to stress in the practice of psychiatry are considered. There are personality characteristics that might dispose some people toward psychiatry as a career and toward stress. However, there is no evidence to suggest that screening for admission to psychiatry in terms of personality or other psychological factors would be useful or advisable.

Adaptation, Psychological↗
PubMed1994

Microvascular free flaps in head and neck surgery.

This study is a retrospective review of 60 patients who had microvascular free flap reconstructions in the head and neck region. They were all performed over a 10-year period by a single surgeon. The series includes a wide range of flap types and analyses pre-operative risk factors for flap failure as well as complications and outcome. Smoking and advanced age did not appear to prejudice flap survival but peripheral vascular disease, cardiac disease and alcohol withdrawal were found to increase the likelihood of flap failure. The most frequent complications encountered were thrombosis of one of the anastomosis and haematoma. The most successful flap in terms of survival and function was the fasciocutaneous radial forearm flap. The literature is reviewed in relation to the general principles of microvascular free flap surgery and the results of this series are placed in context.

Adolescent↗
PubMed1993

Specialist practice for minor oral surgery: a comparative audit of third molar surgery.

Cost efficiency of removing third molars in a practice specialising in minor oral surgery was compared to that of a hospital oral surgery department. A total of 100 patients treated in each locality were prospectively audited during the financial year 1989-90. Surgical complexity, waiting time, complications and patient satisfaction were compared. The hospital cases were costed individually and compared to fees received for the patients treated in the practice. The practice fees were also compared to average expenses as assessed by the Dental Rates Study Group Inland Revenue Enquiry. Patients were treated more promptly and at a lower cost in the specialist practice with no adverse effect on quality as assessed by complications and patient satisfaction. Surgical complexity was not a contraindication to practice treatment but some patients may be better treated in hospital because of medical or social circumstances. Patient charges for treatment carried out under General Dental Service regulations are a serious impediment to the viability of a specialist oral surgery practice.

Adolescent↗
PubMed1993

Comparison of arthrotomographic and magnetic resonance images of 50 temporomandibular joints with operative findings.

Arthrotomography and magnetic resonance imaging (MRI) were carried out on 50 temporomandibular joints (TMJs) in 48 patients who were being considered for surgery for clinically diagnosed internal derangement. The patients presented over a 4-year period with pain and dysfunction which had failed to respond to conservative management. Open surgery was carried out on all TMJs and operative findings compared with the results of imaging. The clinical diagnosis of internal derangement was confirmed in every case by imaging and at surgery. Arthrotomography over-diagnosed non-reducibility of an anteriorly displaced meniscus and perforation. MRI over-diagnosed non-reducibility to a lesser extent and under-diagnosed perforation. MRI demonstrated neither bony changes nor adhesions. Dynamic arthrotomography produced the best images of meniscal derangement in function and the pre-arthrogram tomograms were the best indicator of osseous abnormality. Arthrotomography was the preferred imaging technique.

Adolescent↗
PubMed1990

Bone marrow stromal cell bioactivation and detoxification of the benzene metabolite hydroquinone: comparison of macrophages and fibroblastoid cells.

Bone marrow stroma consists predominately of two cell types, macrophages and fibroblastoid stromal cells, which regulate the growth and differentiation of myelopoietic cells via the production of growth factors. We have previously shown that macrophages are more sensitive than fibroblastoid stromal cells (LTF cells) to the toxic effects of the benzene metabolite hydroquinone. In this study, the role of selective bioactivation and/or deactivation in the macrophage-selective effects of hydroquinone was examined. LTF and macrophage cultures were incubated with 10 microM [14C]hydroquinone to examine differential bioactivation. After 24 hr, the amount of 14C covalently bound to acid-insoluble macromolecules was determined. Macrophages had 16-fold higher levels of macromolecule-associated 14C than did LTF cells. Additional experiments revealed that hydroquinone bioactivation to covalent-binding species was hydrogen peroxide dependent in macrophage homogenates. Covalent binding in companion LTF homogenates was minimal, even in the presence of excess hydrogen peroxide. These data suggest that a peroxidative event was responsible for bioactivation in macrophages and, in agreement with this, macrophages contained detectable peroxidase activity whereas LTF cells did not. Bioactivation of [14C]hydroquinone to protein-binding species by peroxidase was confirmed utilizing purified human myeloperoxidase in the presence of hydrogen peroxide and ovalbumin as a protein source. High performance liquid chromatographic analysis of incubations containing purified myeloperoxidase, hydroquinone, and hydrogen peroxide showed that greater than 90% of hydroquinone was removed and could be detected stoichometrically as 1,4-benzoquinone. 1,4-Benzoquinone was confirmed as a reactive metabolite formed from hydroquinone in macrophage incubations using excess GSH and trapping the reactive quinone as its GSH conjugate, which was measured by high performance liquid chromatography with electrochemical detection. The activity of DT-diaphorase, a quinone reductase that has been invoked as a protective mechanism in quinone-induced toxicity, was 4-fold higher in LTF cells than macrophages. These data suggest that the macrophage-selective toxicity of hydroquinone results from higher levels of peroxidase-mediated bioactivation and/or lower levels of DT-diaphorase-mediated detoxification.

Animals↗
PubMed1988

Bioactivation of catechol in rat and human bone marrow cells.

o-Benzoquinone-glutathione (GSH) conjugate formation and covalent binding of [14C]catechol to protein were utilized as probes of bioactivation of catechol in both rat and human white bone marrow cell systems. Conjugate formation and binding occurred in the absence of exogenous hydrogen peroxide, but were markedly stimulated by its addition. Protein-binding and conjugate formation using rat cells in the presence of exogenous peroxide were increased by the presence of phenol whereas GSH and hydroquinone inhibited binding. Similarly, protein-binding in the absence of exogenous peroxide was inhibited by GSH and exacerbated by phenol. Prostaglandin synthase, the peroxidatic function of which may also utilize hydrogen peroxide as a substrate, appeared on the basis of experiments using arachidonic acid to play only a minor role in bioactivation of catechol in rat bone marrow cells. These results show that peroxide-dependent bioactivation of catechol occurs in rat and human bone marrow cells and that hydroquinone and GSH inhibit whereas phenol stimulates bioactivation.

Animals↗
PubMed1988

Oxidation of catechol by horseradish peroxidase and human leukocyte peroxidase: reactions of o-benzoquinone and o-benzosemiquinone.

The metabolism of secondary phenolic metabolites of benzene, such as catechol, by peroxidases represents one possible mechanism underlying benzene-induced myelotoxicity. The oxidation of catechol by horseradish peroxidase and peroxidases present in human leukocytes was therefore examined. Peroxidatic oxidation resulted in o-benzoquinone production, which was characterized as its bromothiophenol adduct. o-Benzoquinone-glutathione conjugates were formed during peroxidatic oxidation of catechol in the presence of glutathione. Both mono- and diglutathione conjugates were detected. As much as 80% of catechol removed during peroxidatic oxidation could be recovered as glutathione conjugates of o-benzoquinone. Glutathione had no inhibitory effect on the removal of catechol during peroxidatic oxidation. In the presence of divalent cations (Mg2+, Zn2+), however, which slow the rate of o-semiquinone disproportionation, glutathione was found to inhibit catechol removal. This suggests that in the absence of stabilizing metal, reduction of the o-benzosemiquinone radical by glutathione cannot compete with other rapid reactions of the radical such as disproportionation. No interaction of the o-benzosemiquinone radical with oxygen could be detected even in the presence of stabilizing metals or superoxide dismutase which inhibits the reverse reaction of the SQ + O2 in equilibrium Q + O.2 equilibrium. Thus, under physiological conditions, glutathione and oxygen would not be expected to reduce or oxidize respectively the o-benzosemiquinone radical. These data show that the generation of thiol conjugates of o-benzoquinone can be used as probes of peroxidatic oxidation of catechol.

Benzoquinones↗