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Biomedical subjects

C Roffe

Publications and source records attributed to C Roffe.

16 recordsLinked to original sources
PubMed2001

Effect of hemiparetic stroke on pulse oximetry readings on the affected side.

BACKGROUND AND PURPOSE: Hypoxia is common after stroke, and monitoring by pulse oximetry is suggested in the acute phase. Physical changes on the affected side or intravenous infusions may affect oximeter readings. This study was designed to test whether pulse oximetry recordings are the same on the affected and nonaffected sides in stroke patients. METHODS: Oxygen saturation (SpO(2)) and heart rate (HR) were assessed simultaneously in the left and right hands in patients with hemiparetic stroke over a 3-hour period with 2 Minolta Pulsox-3i oximeters attached to the index fingers. RESULTS: Fifteen patients (53% men; 67% left hemiparesis; mean age, 73 years [SD, 7.5 years]) were recruited. HR and SpO(2) (12 measurements per minute) were monitored. The maximum difference between simultaneous left and right arm readings was 2% SpO(2). HR fluctuated more, but no affected/nonaffected side pattern was seen. Means for each patient of HR and SpO(2) for the affected and nonaffected sides were compared by t tests. Mean SpO(2) was 96% (SD, 1%) on both sides. Mean HR was 81 bpm (SD, 11 bpm) on the affected side and 80 bpm (SD, 10 bpm) on the nonaffected side. There was no significant difference between the 2 sides for either parameter (n=15; P=0.86 for SpO(2) and P=0.91 for HR). CONCLUSIONS: Oximeters can be attached to either the affected or nonaffected side in hemiparetic stroke.

Aged↗
PubMed1998

Ageing of the heart.

Ageing of the heart is associated with a number of characteristic morphological, histological and biochemical changes. However, not all observed changes with age are associated with a deterioration in function. The high prevalence of hypertension and ischaemic heart disease makes distinction between normal ageing changes and the effects of underlying cardiovascular disease processes difficult. In this review, an attempt has been made to separate age-related changes from those related to disease, and to outline their significance for cardiac performance. Disease-independent changes in the ageing heart which are associated with a reduction in function include a reduction in the number of myocytes and cells within the specialised conduction tissue, the development of cardiac fibrosis, a reduction in calcium transport across membranes, lower capillary density and decreases in the intracellular response to beta-adrenergic stimulation. Other characteristic changes, such as epicardial fat deposition and 'brown atrophy' due to intracellular lipofuscin deposits, appear to be merely symptomatic of the ageing process without any obvious effects on function. Some of the age-associated changes in the heart can be reversed, at least partially, by exercise or specific drugs. It remains, however, unclear whether this would result in any definite advantages for the individual. The mechanisms guiding proliferation or non-proliferation of myocytes and the development of fibrosis are current topics for research and may lead to new preventive approaches to ageing processes in the heart.

Adult↗
PubMed1996

The effect of afterload and angiotensin II on proto-oncogene mRNA levels in the isolated working rat heart.

OBJECTIVES: The proto-oncogenes c-fos, c-myc and H-ras have been shown to rise in a characteristic pattern in the left ventricle undergoing hypertrophy in the coarctation model of experimental hypertension and there is some evidence to suggest that they might play a role in the initiation of hypertrophic growth. However, in vivo studies do not discriminate between the direct effects of pressure and pressure-independent trophic stimuli such as angiotensin II. To examine these influences separately we studied isolated working hearts exposed to different afterloads in the presence or absence of angiotensin II. METHODS: Hearts from normotensive female Wistar rats were perfused with a modified Krebs-Henseleit solution, with and without angiotensin II (100 nmol/1) and exposed to low (60 mmHg) or high (140 mmHg) afterload (n > 17/group). Proto-oncogene mRNA induction in the left ventricle was assessed by Northern blot analysis. RESULTS: Aortic pressures were 101 +/- 14/63 +/- 6 mmHg (mean +/- s.d.) with low and 175 +/- 13/93 +/- 20 mmHg with high afterload; hearts in both groups maintained a stable cardiac output over 240 min, except for high afterload hearts not perfused with angiotensin II, which showed a 59% drop by the end of the experiment (P < 0.001). There was a 50% (32%, 72%) (geometric mean and 95% confidence interval) increase of c-myc and 54% (27%, 86%) increase in c-fos, but a 32% (25%, 40%) suppression of H-ras with high (140 mmHg) as compared with low (60 mmHg) afterloads (P < 0.0001 for each). There was no significant difference in c-myc and c-fos induction with different levels of high afterload (110, 120, 140 mmHg), but for H-ras suppression progressively increased with increasing afterload (P = 0.003). At high afterload, levels of c-fos rose at 30 min and peaked at 60 min, c-myc continued to rise up to 240 min, and H-ras was suppressed at all four time points. The addition of angiotensin II (100 nmol/l) to the perfusate resulted in 18% (6%, 28%; P = 0.006) lower c-myc levels, 12% (-6%, 28%; P = 0.18) lower c-fos levels and an 11% (-0.1%, 24%; P = 0.056) increase of H-ras. CONCLUSION: The isolated perfused working rat heart is capable of performing stably for a period of at least 240 min at high afterload pressures comparable to those encountered in hypertension. A proto-oncogene induction similar to that seen in the hypertrophying heart can be induced by increased pressure alone, without the mediating effects of circulating angiotensin II. Hearts perfused with angiotensin II showed a more stable performance at high levels of afterload which was associated with a minor attenuation of pressure-induced changes in proto-oncogene expression.

Angiotensin II↗
PubMed1994

Investigation of the effects of intravenous magnesium sulphate on cardiac rhythm in acute myocardial infarction.

OBJECTIVE: To examine the effect of doubling serum magnesium concentration on the incidence of arrhythmias in patients with suspected acute myocardial infarction. DESIGN: Randomised double blind clinical trial. SETTING: Coronary care unit of a teaching hospital. PATIENTS: Clinical data were collected on 2316 randomised patients with suspected acute myocardial infarction. Holter monitoring was performed in a subgroup of 70 patients and analysed in 48 patients in whom acute myocardial infarction was confirmed. INTERVENTIONS: By random allocation, patients received either an intravenous loading dose of 8 mmol magnesium sulphate over five minutes plus 65 mmol over the next 24 hours, or equal volumes of saline. MAIN OUTCOME MEASURES: (a) Clinically documented arrhythmias; (b) use of antiarrhythmic treatments, cardioversion, and insertion of a pacemaker; (c) incidence of all abnormal rhythms during Holter monitoring. RESULTS: In the main trial the incidence of rhythm disturbance while in the coronary care unit (expressed as the odds ratio (OR) for magnesium: placebo and its 95% confidence interval) was not significantly different between treatment groups for ventricular fibrillation (OR 0.74; 0.46 to 1.20), ventricular tachycardia (OR 0.87; 0.63 to 1.20), supraventricular tachycardia (OR 0.69; 0.38 to 1.26), atrial fibrillation (OR 0.92; 0.69 to 1.23), or heart block of any degree (OR 1.17; 0.83 to 1.65). Sinus bradycardia was significantly more common in the magnesium group (OR 1.38; 1.03 to 1.85; p = 0.02). These findings were corroborated by the use of treatments for rhythm disturbance and the data from Holter monitoring. CONCLUSION: The regimen of intravenous magnesium sulphate used here had no significant effect on arrhythmia in acute myocardial infarction. The reduction in mortality that has been shown with this form of treatment is not attributable to suppression of life threatening rhythm disturbances.

Aged↗
PubMed1994

Anticholinergic premedication for fibreoptic bronchoscopy.

Atropine is routinely used as part of the premedication regimen for fibreoptic bronchoscopy. This study was performed, firstly, to evaluate the effect of anticholinergic agents on the ease of bronchoscopy, haemodynamic parameters and patient comfort during the procedure; and secondly, to compare atropine with glycopyrrolate, a newer acetylcholine antagonist which is claimed to cause less tachycardia and sedation, whilst suppressing salivation more effectively. One hundred and ninety consecutive patients were randomly allocated to three treatment groups: diazepam 5 mg; diazepam 5 mg + atropine 600 micrograms; and diazepam 5 mg + glycopyrrolate 300 micrograms. Diazepam was given orally one hour before bronchoscopy, and glycopyrrolate/atropine intramuscularly 30 min before bronchoscopy. All patients received thalamonal intravenously, lignocaine gel into one nostril, and lignocaine by transtracheal injection just prior to the procedure. The incidence of bronchoscopy related haemodynamic problems was similar in all three groups. Troublesome coughing, as observed by the operator, was less frequent with glycopyrrolate (control 51%, atropine 42%, glycopyrrolate 30%), as was patient movement (40%, 32%, 19%, respectively). Uncomfortable dryness of the mouth was most common with glycopyrrolate (37%, 32%, 66%, respectively), but overall assessment of discomfort, and the number of patients who would agree to a repeat bronchoscopy (73%, 76%, 70%, respectively) were very similar in all three groups. In conclusion, the differences between the three groups were slight. Glycopyrrolate made the bronchoscopy slightly easier for the operator because of significantly improved cough and movement suppression, though atropine was marginally preferable in terms of patient comfort.

Administration, Oral↗
PubMed1992

Intravenous magnesium sulphate in suspected acute myocardial infarction: results of the second Leicester Intravenous Magnesium Intervention Trial (LIMIT-2)

The cardiovascular actions of the magnesium ion at pharmacological concentrations include coronary and systemic vasodilatation, platelet inhibition, and antiarrhythmic effects. Magnesium has also been reported to protect myocardial tissue in experimental models of ischaemia and reperfusion. Several small clinical trials in suspected acute myocardial infarction have suggested that early mortality can be reduced by intravenous infusion of magnesium salts in the acute phase, but none has been of sufficient size to be conclusive. We therefore conducted a randomised, double blind, placebo controlled study in 2316 patients with suspected acute myocardial infarction who received either intravenous magnesium sulphate (8 mmol over 5 min followed by 65 mmol over 24 h) or physiological saline. The primary outcome measure was 28-day mortality, which was ascertained in 99.3% of patients. The groups were well balanced for prognostic factors. By intention-to-treat analysis mortality from all causes was 7.8% in the magnesium group and 10.3% in the placebo group (2p = 0.04), a relative reduction of 24% (95% confidence interval 1-43%). Within the coronary care unit the incidence of left ventricular failure was reduced by 25% (7-39%) in the magnesium group (2p = 0.009). There was no significant difference between the groups in the incidence of heart block or the use of antiarrhythmic drugs, direct-current cardioversion, or temporary pacing. Myocardial infarction was confirmed in 65% of each group, with closely similar rises in cardiac enzymes. The side-effects of magnesium treatment were transient flushing, related to speed of injection of the loading dose, and an increased incidence of sinus bradycardia (2p = 0.02). Exploratory subgroup analyses of 28-day mortality did not indicate any effect modification by thrombolysis or aspirin, or by previous treatment with beta blockers, calcium antagonists, or diuretics. Intravenous magnesium sulphate is a simple, safe, and widely applicable treatment. Its efficacy in reducing early mortality of myocardial infarction is comparable to, but independent of, that of thrombolytic or antiplatelet therapy.

Aged↗
PubMed1991

Aplastic anaemia in systemic lupus erythematosus: a cellular immune mechanism?

Aplastic anaemia is a rare complication of systemic lupus erythematosus (SLE). The mechanism is unclear but is thought to be related to an autoantibody to bone marrow precursors of haematopoiesis. We report a case of SLE related aplastic anaemia in which therapy with methylprednisolone and high dose cyclophosphamide followed by prednisolone and azathioprine resulted in complete clinical and haematological remission. Bone marrow cultures showed inhibition of erythropoiesis when incubated with acute and remission serum. Myeloid colony growth was not affected by either serum. The serum inhibitor we demonstrated was only active in vitro, and we postulate that the mechanism for marrow aplasia may have been an autoimmune cellular process.

Adult↗
PubMed1991

An audit of patients attending a general medical follow-up clinic.

Of the 418 consecutive patients attending a general medical clinic for follow-up, 113 (27%) had appointments in another medical clinic for the same or a related problem; 98 of them (87%) were attending a clinic in a different hospital. The reasons for multiple clinic attendance were routine follow-up after hospital admission in 55 (49%), referrals from general practitioners to more than one clinic in 33 (30%), and cross-referrals from the 'parent' medical firm in 19 (17%). In six patients no clear reason for multiple attendances could be identified. More than half (55%) were over 65 years old, 45% lived more than five miles from the hospital, and 78% depended on ambulance, friends, or relatives for transport. We suggest that follow-up attendances at outpatient clinics should be stringently reviewed and should only be maintained if a clear reason can be identified. This would not only ensure a more effective service overall but would also save patients and relatives from inconvenience.

Aged↗
PubMed1990

Accidental self administration of xylazine in a veterinary nurse.

A 19 year old male veterinary nurse accidentally injected himself with 200 mg of xylazine (a muscle relaxant and sedative used in veterinary practice). He subsequently became comatose, hypotensive, bradycardic and acidotic. He required intensive supportive therapy, and made a full recovery over the next few hours. Xylazine toxicity in humans is very rare, and the effects are discussed.

Accidents, Occupational↗
PubMedDate not supplied

Madness and care in the community: a medieval perspective.

Care in the community for insane people today is more a matter of expert provision than communal support. In consequence, although they are no longer confined to hospital, mentally ill people largely remain marginalised in a society that does not have the resources, nor often the inclination, to take responsibility for their care. The experience of insane people in medieval England seems to have been of a different order, as shown by a particularly well documented case dating from 1383. From the late 13th century congenital idiots were protected by law. Care of lunatics, by contrast, was primarily the responsibility of the family. However, where the family could not or was unwilling to provide, provision was made by the crown. Through the instrument of the inquisition, the diagnosis and social circumstances of each case were determined by commissioners in consultation with a local jury and all interested parties, including the subject himself or herself. The best interests of the subject remained a prime concern, and the settlement that was ordained was tried and enforced in law. The process was confined to those with real or personal estate, but it encompassed poor as well as rich and proved, through the close identity of the local community with the process, to be a sophisticated and effective mechanism for maintaining and sustaining insane people. Unlike today, care in the community was a communal activity that ensured a truly public provision for those who could not look after themselves.

Attitude to Health↗