Search PubMed⌕ Search

Biomedical subjects

J Chalmers

Publications and source records attributed to J Chalmers.

212 records · Page 12Linked to original sources
PubMedDate not supplied

Efferent mechanisms responsible for the bradycardia produced by lesions coinciding with the A1 group of central catecholamine neurons in the conscious rabbit.

The effector mechanisms responsible for the bradycardia evoked by bilateral lesions of the brainstem coinciding with the A1 catecholamine cells were analyzed in four groups of rabbits. Sham or lesion operations were carried out in animals with intact cardiac effectors, with cardiac sympathetic block induced by propranolol, with cardiac vagal block induced by methylscopolamine and with total cardiac autonomic block induced by the use of both drugs together. Lesions produced a transient increase in blood pressure of 25 (s.e.m. = 4) mmHg and a transient bradycardia, or increase in heart period of 141 (s.e.m. = 18) ms. The bradycardia had both baroreflex-independent and baroreflex-dependent components as determined from analysis of stimulus response curves relating heart period to mean arterial pressure. The 'baroindependent' component of the bradycardia, measured as a lengthening in heart period, ranged from 35-49 ms in the four groups of animals and was unaffected by administration of propranolol alone, methylscopolamine alone, or of both together. These findings suggest that the baroindependent slowing of the heart is not mediated through changes in activity of either the cardiac sympathetic nerves or of the vagal fibres innervating the heart. The 'baroreceptor' component of the bradycardia reflects that portion of the decrease in heart rate resulting directly from the increase in blood pressure. This component was found to account for a lengthening in the heart period of 81 (s.e.m. = 23) ms in animals with intact effector mechanisms: it was virtually abolished by methylscopolamine (0 ms, s.e.m. = 13) but not significantly affected by propranolol (54 ms, s.e.m. = 25), indicating that this barodependent component is predominantly mediated through the vagus.

Animals↗
PubMedDate not supplied

Impact of guidelines for antihypertensive treatment on clinical practice.

Many Guidelines and Consensus Statements were published in 1993 and 1994. The pressure to produce these guidelines comes from clinicians faced with rapid change, from a wish to provide an independent authoritative view rather than rely on commercial promotion of particular treatments, and from governments seeking assistance with the allocation of scarce resources. Evaluation of the impact that guidelines exert on clinical practice is notoriously difficult, but has been attempted using the self-report questionnaire, or the more reliable but expensive analysis of actual practice data, before and after publication of the guidelines. Rigorous evaluation has been attempted and reported in North America and in Europe, in relation to surgical and obstetrical procedures and psychiatric disorders as well as medical treatments. Specific evaluation of the impact of recommendations from the Joint National Committee in the USA, for the treatment of hypertension, has also been attempted, as well as surveys of doctors' perceptions of Consensus Statements. The evidence available suggests that the main value obtained from Guidelines and Consensus Statements lies in their capacity to codify good or "best practice", at times of rapid change in a particular field. They also serve as a source of support for local opinion leaders, and as they are usually produced by respected authors they have substantial influence with Government. Guidelines are not effective in producing rapid change in clinical practice. If a change in practice is sought a more comprehensive program of action is necessary, with guidelines as one useful element.

Antihypertensive Agents↗
PubMedDate not supplied

Blood pressure lowering for the prevention of cognitive decline in patients with cerebrovascular disease. PROGRESS Management Committee. Perindopril Protection Against Recurrent Stroke Study.

Cerebrovascular disease and high blood pressure both appear to increase the risk of vascular dementia. PROGRESS aims to investigate whether blood pressure lowering with an angiotensin coverting enzyme inhibitor-based regimen will reduce the risk of cognitive impairment in patients with a history of stroke or transient ischaemic attack. A total of at least 6000 patients will be randomised to receive perindopril (+/- indapamide) or matching placebo(s), with treatment and follow-up scheduled to continue for at least 4 years. Substudies will investigate the effects of treatment on cognitive decline in subgroups defined by apo-E genotype and on white matter lesions assessed by magnetic resonance imaging. Final results from the study should be available in 2001.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

Implementation of guidelines for management of hypertension.

There is now good evidence that the publication of guidelines as a stand-alone exercise produces little change in clinical practice and no change in health outcome. Randomised controlled studies of the effectiveness of Continuing Medical Education (CME) and of interventions to change professional practice have clearly shown that communications restricted to the distribution of published or printed educational materials is not effective. Rather, these studies indicate that the publication and distribution of practice guidelines must be embedded in a comprehensive package of interventions reaching clinicians in their local practice site, in order to change physician performance and health outcomes.

Education, Medical, Continuing↗
PubMedDate not supplied

The importance of drug combinations for effective control of hypertension.

The need for drug combinations in the management of hypertension arises from the fact that the majority of hypertensive patients need at least two drugs to control the blood pressure to below 140/90 mmHg. The importance of achieving such goal blood pressures is emphasised by longitudinal studies demonstrating that the achieved blood pressure is the main determinant of outcome and from population surveys in a number of countries that reveal that in general, less than 30% of treated hypertensive patients have blood pressures below 140/90 mmHg. Good combinations of antihypertensive drugs use agents from different classes with different primary actions so that the hypotensive effects are fully additive while side effects are minimised. The particular value of combining drugs for treating hypertension is that it permits the use of low doses, which in turn improves adherence to therapy and control of hypertension. Effective combinations for the treatment of essential hypertension and of systolic hypertension in the elderly are discussed, as are the potential advantages of fixed low dose combinations.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

1999 World Health Organization-International Society of Hypertension Guidelines for the management of hypertension. Guidelines sub-committee of the World Health Organization.

The present Guidelines were prepared by the Guidelines Sub-Committee of the World Health Organization-International Society of Hypertension (WHO-ISH) Mild Hypertension Liaison Committee, the members of which are listed at the end of the text. These guidelines represent the fourth revision of the WHO-ISH Guidelines and were finalised after presentation and discussion at the 7th WHO-ISH Meeting on Hypertension, Fukuoka, Japan, 29th Sept-1st Oct, 1998. Previous versions of the Guidelines were published in Bull WHO 1993, 71:503-517 and J Hypertens 1993, 11:905-918.

Adult↗
PubMedDate not supplied

Women in medicine.

Explore the source record for details and available documents.

Australia↗
PubMedDate not supplied

Global impact of stroke.

As the developing world becomes increasingly industrialized and urbanized, and its vast populations adopt more westernized diets and lifestyles, the burden of cardiovascular disease and disability is growing at an alarming rate. The results of prospective observational studies conducted in both western and eastern populations have established the strong association between the primary incidence of stroke and the level of blood pressure. Further, randomized clinical trials of antihypertensive therapy have demonstrated a reduction in primary stroke risk. Among persons with a history of cerebrovascular disease, data from the United Kingdom Transient Ischemic Attack Aspirin Trial (UKTIA) has demonstrated a similar relationship between blood pressure and secondary stroke risk. Trials of blood-pressure lowering in patients with a history of cerebrovascular disease also suggested a reduction in stroke risk. However, patients numbers in these trials were small, and the results were not conclusive. PROGRESS (Perindopril pROtection aGainst Recurrent Stroke Study) is a large, randomized, double-blind, controlled trial designed to provide a definitive answer to these questions. Its primary aim is to determine the effect of blood-pressure lowering on stroke incidence in patients with a history of a previous stroke or transient ischemic attack. A total of 6,105 patients were randomized to receive perindopril (plus indapamide) or placebo in seven regions of the world. The current mean follow-up period exceeds 30 months, and a total follow-up period of at least 4 years is planned. Secondary outcomes include the incidence of other major cardiovascular events, such as myocardial infarction, and of cognitive decline and dementia. Both the major event rate and the degree of adherence to randomized therapy exceed initial projections, which suggests that the study should have the power to achieve its main objectives by the planned completion date of 2001.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

One year comparative trial of metformin and glipizide in type 2 diabetes mellitus.

Forty-eight diabetic subjects with diet-failed Type 2 mellitus, aged 40-69 years, were randomised to metformin (24 patients) or glipizide (24 patients) therapy, and followed prospectively for 12 months. Most subjects were obese. Metformin gave better fasting plasma glucose control compared to glipizide at 24 (p < 0.01), 36 (p < 0.05) and 52 weeks (p < 0.05) with a lower HbA1 concentration at 52 weeks (p < 0.05). Metformin treated patients lost weight whereas glipizide treated subjects gained weight. The weight change between the treatment groups reached significance at 4 weeks (p < 0.05) and was highly significant (p < 0.001) at 8, 12, 24, 36 and 52 weeks. There were no significant changes in either fasting plasma lipid or blood lactate levels in either the metformin or glipizide treated groups. Both drugs caused a similar reduction in albumin excretion rates. In conclusion, metformin gave better glycaemic control than glipizide, with weight loss rather than weight gain in obese Type 2 patients.

Adult↗
PubMedDate not supplied

Lingual infarction in cranial arteritis.

An unusual case is described of infarction of the tongue as a presentation of cranial arteritis. The lingual necrosis may have been precipitated in part by the use of ergotamine to relieve the headache of the temporal arteritis, mistaken initially for migraine. The patient recovered with high-dose steroid therapy.

Aged↗