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Biomedical subjects

D Clarke

Publications and source records attributed to D Clarke.

At least 37 records · Page 2Linked to original sources
PubMed2002

An unusual case of stridor after thyroidectomy.

Twelve days after subtotal thyroidectomy, an air pocket developed in a patient's neck. The pressure in this pocket had gradually increased as small amounts of air, probably associated with coughing, came out of a tiny hole in the trachea to form a pneumocoele. This produced limited surgical emphysema, causing venous congestion and oedema of the soft tissues of the larynx, which in turn led to increasing airway obstruction. We believe that this is the first reported case of a pneumocoele that gradually increased in size, causing airway obstruction that was almost certainly due to secondary laryngeal oedema.

Aged↗
PubMed2002

Flexible sigmoidoscopy in general practice.

OBJECTIVE: Flexible sigmoidoscopy (FS) is increasingly being accepted as the method of choice for initial investigation of rectal bleeding and other lower gastrointestinal symptoms. The aim of this study was to assess the feasibility of FS in general practice and to compare the yield, cost and efficiency of a service provided by a consultant surgeon and a General Practitioner (GP). SUBJECTS AND METHODS: A prospective study of FS was undertaken on 430 unsedated patients with symptoms suggestive of lower bowel disease in two general practices. RESULTS: The yield was comparable to hospital based data. Fifteen (3.5%) cancers were detected, of which 40% were Dukes A, and 46 (10.7%) adenomatous polyps. Cost per patient examination by a GP including capital costs, depreciation of equipment, and training was calculated to be cheaper or at least equivalent to a hospital-based service but inefficient due to the low numbers examined per month. There were no complications and no missed cancers after a minimum follow up of 2 years. CONCLUSIONS: The results suggest that FS can be safely performed by a suitably trained GP in health centres, but better utilization of equipment and value for money would be obtained by providing the service for a group of practices rather than a single practice as in this study.

Journal Article↗
PubMed2002

Pulmonary barotrauma-induced cerebral arterial gas embolism with spontaneous recovery: commentary on the rationale for therapeutic compression.

Pulmonary barotrauma-induced cerebral arterial gas embolism (CAGE) continues to complicate compressed gas diving activities. Inadequate lung ventilation secondary to inadvertent breath holding or rapid buoyant ascent can quickly generate a critical state of lung over-pressure. Pulmonary over-pressurization may also occur as a consequence of acute and chronic pulmonary pathologies. Resulting barotrauma frequently causes structural failure within the terminal distal airway. Respiratory gases are then free to embolize the systemic circulation via the pulmonary vasculature and the left heart. The brain is a common target organ. Bubbles that enter the cerebral arteries coalesce to form columns of gas as the vascular network narrows. Small amounts of gas frequently pass directly through the cerebral circulation without occlusion. Larger columns of gas occlude regional brain blood flow, either transiently or permanently, producing a stroke-like clinical picture. In cases of spontaneous redistribution, a period of apparent recovery is frequently followed by relapse. The etiology of relapse appears to be multifactoral, and chiefly the consequence of a failure of reperfusion. Prediction of who will relapse is not possible, and any such relapse is of ominous prognostic significance. It is advisable, therefore, that CAGE patients who undergo spontaneous recovery be promptly recompressed while breathing oxygen. Therapeutic compression will serve to antagonize leukocyte-mediated ischemia-reperfusion injury; limit potential re-embolization of brain blood flow, secondary to further leakage from the original pulmonary lesion or recirculation of gas from the initial occlusive event; protect against embolic injury to other organs; aid in the resolution of component cerebral edema; reduce the likelihood of late brain infarction reported in patients who have undergone spontaneous clinical recovery; and prophylax against decompression sickness in high gas loading dives that precede accelerated ascents and omitted stage decompression.

Adult↗
PubMed2001

A survey of attitudes to parent-doctor conflicts over treatment for children.

AIMS: To investigate professional and public attitudes to the intervention of the law when parents and doctors disagree about the medical treatment of children. METHODS: A cross-sectional survey of academic staff at the University of Otago. Random samples of academic medical practitioners and non-Health Sciences academic staff completed written questionnaires, including open and closed questions. Questions focussed on the Liam Williams-Holloway (W-H) and Tovia Laufau (TL) cases. RESULTS: The response rate was 107/164 (65%) of eligible staff. Support for doctors seeking treatment orders was strong (77% in the W-H case, and in the TL case, 70% believed an order should have been sought). Women were less likely than men to support a treatment order, significantly in the W-H case. There were no significant differences between medical and non-medical respondents. Court processes were viewed as confrontational and a last resort only after mediation failed. Scientific evidence was rated as the most important consideration in treatment decisions, followed by likely outcome, establishment of trust between parents and doctors, and the age of the child. CONCLUSIONS: Among this highly educated group there was strong support for seeking treatment orders in the child's best interests. But various mediation options were preferred and should be explored further. More evidence is needed on the success of treatment orders and on the attitudes of a more representative sample of the population.

Attitude of Health Personnel↗
PubMed2001

Sentinel node biopsy in breast cancer: ALMANAC trial.

Sentinel node biopsy of breast cancer is becoming an increasingly popular topic. The concept of the sentinel node being the first lymph node to contain metastatic cancer within a tumor's lymphatic basin was introduced by Cabanas, a South American surgeon, following his work on carcinoma of the penis. Morton and his colleagues then applied this principle to malignant melanomas, and more recently this concept has gained popularity for carcinoma of the breast. In breast cancer patients, the fact that a sentinel node can be localized and the suggestion that the sentinel node is representative of the axillary nodal status has been confirmed by a number of studies across the world. Most authors writing on this subject, however, end with a caution that the results of randomized trials are needed before this new surgical technique can be accepted as part of routine breast cancer management. The Medical Research Council of the United Kingdom has funded the audit phase of a multicenter, two phase, randomized trial called the Axillary Lymphatic Mapping Against Nodal Axillary Clearance (ALMANAC) trial, which will compare standard axillary management with sentinel node-guided axillary management. The aims and protocol of the trial are discussed in detail here.

Axilla↗
PubMed2001

Macrophages transfected with adenovirus to express IL-4 reduce inflammation in experimental glomerulonephritis.

Nephrotoxic nephritis (NTN) is characterized by acute macrophage-dependent inflammation and serves as a model of human glomerulonephritis. In this study we have transfected rat macrophages with recombinant adenovirus expressing IL-4 (Ad-IL4) and demonstrated that these transfected macrophages develop fixed properties as a result of transfection, as shown by reduced NO production in response to IFN-gamma and TNF. Ad-IL4-transfected macrophages localized with enhanced efficiency to inflamed glomeruli after renal artery injection in rats with NTN compared with adenovirus expressing beta-galactosidase (Ad-beta gal)-transfected macrophages and produced elevated levels of the cytokine in glomeruli in vivo for up to 4 days. The delivery of IL-4-expressing macrophages produced a marked reduction in the severity of albuminuria (day 2 albuminuria, 61 +/- 15 mg/24 h) compared with unmodified NTN (day 2 albuminuria, 286 +/- 40 mg/24 h; p < 0.01), and this was matched by a reduction in the number of ED1-positive macrophages infiltrating the glomeruli. Interestingly, the injection of IL-4-expressing macrophages into single kidney produced a marked reduction in the numbers of ED1-positive macrophages in the contralateral noninjected kidney, an effect that could not be mimicked by systemic delivery of IL-4-expressing macrophages. This implies that the presence of IL-4-expressing macrophages in a single kidney can alter the systemic development of the inflammatory response. Macrophage transfection and delivery provide a valuable system to study and modulate inflammatory disease and highlight the feasibility of macrophage-based gene therapy.

Adenoviridae↗
PubMed2001

Relationship of psychosis to aggression, apathy and function in dementia.

BACKGROUND: Psychosis has been associated with aggression in dementia, but the nature of this relationship has been unclear. There has been very little research into the relations between apathy and functional status to psychosis in dementia. The purpose of this study is to investigate the relationship between psychosis and aggression, apathy, and functional status in outpatients with dementia. METHODS: The presence of psychosis was assessed by clinical interview and two scales: the Neuropsychiatric Inventory and the Columbia University Scale for Psychopathology in Alzheimer's Disease. The maximum likelihood estimation technique was used to determine the best estimate of the presence of psychosis. Aggression, apathy, and functional status (activities of daily living: ADLs) were measured using structured instruments. RESULTS: Sixty-one subjects were included. The CUSPAD and NPI provided low false positive and negative rates. ANCOVA analyses showed that psychosis was significantly associated with aggression, even when controlling for apathy, depression, and ADLs. Psychosis was related to apathy only when depression was controlled for. Hallucinations were related to impaired basic ADLs, even when depression and apathy were controlled for. CONCLUSIONS: Relationships were found between psychotic symptoms in dementia and aggression as well as apathy and impaired functional status. These relationships suggest pathophysiologic mechanisms and have possible treatment implications.

Activities of Daily Living↗
PubMed2001

Differentiation potential of adult stem cells.

In many different adult tissues, stem cells generate new cells either continuously or in response to injury. Such cells were thought to be limited to generating the types of cells normally present in the tissue where the stem cell resides. However, several different stem-cell populations in the adult have been found recently to be capable of generating additional cell types under certain conditions.

Animals↗
PubMed2001

Evidence for the regulation of levels of plasma adhesion molecules by proinflammatory cytokines and their soluble receptors in type 1 diabetes.

OBJECTIVES: To investigate the regulation of soluble adhesion molecules by tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), and relationships with circulating cytokine receptors, in vivo, in type 1 diabetes. DESIGN: Cross-sectional study. SETTING: University hospital diabetes clinic. SUBJECTS: A total of 47 non-nephropathic, Caucasian type 1 diabetics and 39 nondiabetic controls. OUTCOME MEASURES: Plasma levels of TNF-alpha, IL-6, their soluble receptors and adhesion molecules intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), sE-selectin and von Willebrand factor (vWF), and risk factors for cardiovascular disease. RESULTS: Plasma concentrations of IL-6 were elevated in diabetic patients compared with controls [median (interquartiles) 1.28 (0.89-2.65) vs. 0.66 (0.45-1.73) pg mL(-1): P=0.016], and in these patients IL-6 and soluble IL-6 receptor (sIL-6R) levels correlated with concentrations of sICAM-1 (r = 0.41, P = 0.012 and r = 0.31, P = 0.04, respectively). Tumour necrosis factor-alpha soluble receptor-2 (sTN-FRII), but not TNF-alpha or tumour necrosis factor soluble receptor-1 (sTNFRI), was elevated in diabetic subjects (P = 0.027). Plasma TNF-alpha levels correlated with sVCAM-1 (r = 0.39, P = 0.008), triglycerides (r = 0.36, P = 0.02 1) and diastolic blood pressure (r = 0.35; P = 0.024). Both sTNFRI and sTNFRII correlated with blood pressure (r = 0.46, P = 0.002; r = 0.32, P = 0.034) and triglycerides (r = 0.33, P = 0.033; r = 0.29, P = 0.05). In contrast, HDL-cholesterol and triglyceride were related to sE-selectin (r = -0.45 and +0.45; both P < 0.001). Neither sE-selectin nor vWF were related to cytokine concentrations. Finally, both TNF-alpha and sIL-6R correlated sTNFRI and RII (r = 0.44-0.49, P < 0.001). None of these interactions were apparent in control subjects. CONCLUSIONS: (i) IL-6, through effects on sICAM-1, and TNF-alpha via effects on sVCAM-1, may promote vascular adhesion; (ii) plasma levels of TNF-alpha are associated with dyslipidaemia and increased blood pressure, adding to vascular disease risk; (iii) the actions of both cytokines are probably modified by altered production of soluble receptors in diabetic subjects.

Adult↗
PubMed2001

Large-dose oral dextromethorphan as an adjunct to patient-controlled analgesia with morphine after knee surgery.

Dextromethorphan is a weak N-methyl-d-aspartate (NMDA) receptor antagonist that inhibits spinal cord sensitization in animal models of pain and also inhibits the development of cutaneous secondary hyperalgesia after tissue trauma. Perhaps coadministration of an NMDA antagonist with an opioid would lead to better pain relief, particularly with movement and an opioid-sparing effect. This has been shown for ketamine, but previous studies with dextromethorphan that have used small doses have shown only a modest reduction in morphine requirements with no or minimal changes in the postoperative pain experience. We sought to determine whether a large dose of this drug, just below the maximum tolerated dose, could potentiate morphine analgesia while simultaneously causing a significant improvement in the management of the postoperative pain experience. Sixty-six patients undergoing knee surgery were enrolled in the study. The study design was a prospective, randomized double-blinded comparison with placebo of 200 mg of dextromethorphan given eight hourly. Postoperative pain experiences were assessed by postoperative morphine usage. Visual analog and verbal rating scales were used to assess pain with movement as well as side effects. Dextromethorphan treatment led to a significant but modest reduction in morphine requirements (29.3% P < 0.05) but no reduction in postoperative pain levels. We conclude that increasing orally administered dextromethorphan to near maximum tolerated doses does not provide greater morphine sparing than 20-40 mg given 6-8 hourly as in previous studies. Furthermore we conclude that dextromethorphan does not improve pain scores in a manner expected of a drug with NMDA antagonist properties.

Administration, Oral↗
PubMed2001

Intrathoracic lipoma in a Labrador retriever.

Pyrexia, granulocytosis and hyperglobulinaemia were the main clinical findings in an unusual case of intrathoracic lipoma in a 12-year-old male Labrador retriever. The response to antibiotic and anti-inflammatory treatment was poor, prompting further investigation. Survey radiographs and ultrasonography revealed a cavitated, fluid-filled soft tissue mass in the right hemithorax, which was successfully removed resulting in rapid resolution of clinical signs. Lipomas are rare intrathoracic extrapulmonary tumours. Previously reported clinical signs are dyspnoea and coughing, attributed to the mass effect of the lipoma. The unusual presentation in this case was caused by necrosis of the lipoma, probably owing to torsion of the pedicle attaching it to the cranial mediastinum.

Animals↗