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Biomedical subjects

M Curran

Publications and source records attributed to M Curran.

48 records · Page 3Linked to original sources

Thoracic aortic occlusion: somatosensory evoked potential monitoring and neurologic outcome in a canine model.

Somatosensory evoked potentials (SEPs) were monitored in 17 canines during spinal cord ischemia induced by balloon occlusion of the thoracic aorta. Graded distal aortic hypotension to 40 mmHg in seven animals had no significant effect upon the evoked potential. A significant alteration in the SEP did result in 21 +/- 9.8 minutes when distal aortic pressures were reduced in a graded fashion below 30 mmHg. Acute occlusion of the thoracic aorta (10 animals, distal pressure 15-25 mmHg) was associated with a change in the SEP in 8.4 +/- 4.3 minutes. Continuation of aortic occlusion for 30 minutes beyond an evoked potential change resulted in a moderate to severe motor deficit in all cases. Somatosensory evoked potentials obtained 72-96 hours after the ischemic injury were closely correlated with sensory deficits, but were not predictive of motor examination. Histologic examination of the spinal cords demonstrated central gray necrosis of the lumbar region in all animals with a severe deficit, and a variable degree of neuronal loss in the intermediate and dorsal gray matter zones in animals with moderate deficits. This balloon occlusion method is relevant as a model of spinal cord injury during aortic occlusion, such as may occur during aortic surgery.

Acute Disease↗

Simultaneous electrical and optical measurements show that membrane fusion precedes secretory granule swelling during exocytosis of beige mouse mast cells.

Mast cells show dramatic morphological changes when undergoing exocytosis. We have investigated whether the first of those morphological changes, swelling of the secretory granule, precedes--and therefore possibly initiates--secretion or whether it occurs after fusion of the granule and plasma membranes. We used cell membrane capacitance to detect the moment when granule and plasma membrane become continuous. We measured large capacitance increases, often preceded by transients in capacitance. The rise-times of the capacitance increases were half-maximal at 2-59 msec. We observed cells with high-resolution video microscopy while these measurements were done. The capacitance increase always preceded the granular swelling that leads to exocytosis. To rule out the possibility that fusion was induced by a mechanical stress imparted by the internal pressure of a taut granule, we performed control experiments using cells in which vesicles were shrunken with hyperosmotic solutions. With these flaccid granules, again, the capacitance rise always preceded the swelling of the granules. We conclude that swelling cannot be the driving force for membrane fusion in this system.

Animals↗

Problems in the control of hypertension in the community.

A hypertension survey was conducted in Montreal to determine the extent, nature and distribution of the control of hypertension. Of the 12 055 persons screened in shopping centres, workplaces and a random sample of homes in four census tracts the hypertension was not controlled in 69.0% to 80.3% of those with the condition in each setting. Nearly two thirds of those with hypertension were aware of their condition, 13% were aware but had never been treated, 13% were receiving treatment inadequate to control their hypertension, and 11% had discontinued treatment, most reporting that they had done so on the advice of their physician. Among those screened in their home, discontinuance of therapy was most often reported by those with a low income, but lack of awareness of their condition was no more prevalent in this group than in the other income groups. Efforts to control hypertension should be directed to the variety of causes of lack of control, which may occur with various frequencies in different communities, and for which screening alone may be inadequate.

Adult↗

A survey of attitudes of patients in a department of genitourinary medicine.

A questionnaire concerning clinic organisation was completed by 415 patients attending a department of genitourinary medicine. Most (62.9%) patients preferred to be identified by number rather than by name, and about half (52.7%) did not like mixed waiting rooms. An appointment system as well as having an open clinic was liked by twice as many (44.9%) as those patients (23.6%) against such a system. More information about sexually transmitted diseases in the form of leaflets, etc. at the clinic was requested by most (79.1%) patients and a similar number (82.0%) felt the department itself should be more widely advertised.

Adult↗

Alcohol tolerance in a cholinergic nerve terminal: relation to the membrane expansion-fluidization theory of ethanol action.

Phrenic nerve terminals from rats subjected to long-term ethanol treatment were more resistant to ethanol (in vitro) than terminals from sucrose-fed rats, as measured by the effect of ethanol on the frequency of miniature end plate potentials. Long-term ethanol exposure may thus induce the synthesis of more rigid membrane lipids, reducing membrane "fluidizability". This may provide a neurocellular basis for ethanol tolerance and cross-tolerance with anesthetics and barbiturates.

Animals↗

Mechanisms of ethanol tolerance at a cholinergic nerve terminal.

In vitro rat phrenic nerve-diaphragm preparations illustrated a concentration-dependent increase in the spontaneous release (miniature end-plate potentials, MEPPs) of acetylcholine following acute administration of ethanol. In phrenic nerve terminals from rats subjected to long-term ethanol treatmet, ethanol in vitro was significantly less effective in increasing the frequency of MEPPs. The capacity of ethanol administration to change membrane viscosity and alter sequestration of intracellular Ca2+ is discussed as a possible explanation for the observed effects.

Acetylcholine↗

Evidence-based care: can we overcome the barriers?

Evidence-based care has become the new mantra within the NHS, despite the fact that the concept of applying research to practice has been promoted for several decades. However, literature on the subject suggests that formidable obstacles remain to the integration of research into care delivery. This article describes a study which used Funk et al's (1991a,b) Barriers Scale with a population of nurses in a large teaching hospital in the UK. This scale was specifically developed to identify barriers to the introduction of research into practice, and modified for a UK context. The results suggest that a complex array of barriers exist but that foremost among these is the nature of the organizations within which nurses work. Comparisons are made with data from the USA, and the need to create time for nurses to implement change, and to empower them to do so, is stressed.

Attitude of Health Personnel↗

Posttransplantation diabetes mellitus in heart transplant recipients.

This study was undertaken to investigate the impact of diabetes, which develops after heart transplantation, on infection and patient survival. Nondiabetic patients (366) underwent heart transplantation at our institution between June 1, 1980 and January 12, 1988. Of these patients, 29 (8%) developed posttransplantation diabetes (PTD), defined as a continued need for hypoglycemic agents. The PTD group did not differ significantly from the nondiabetic recipients in age, sex, or human leukocyte antigen type. The average age in the PTD group was 49 years. Average length of follow-up was 21 months (range 4 to 46 months). Eighteen patients are maintained on insulin. Eight patients are on oral hypoglycemic agents. Three patients died while on insulin. The average prednisone dosage in this group is 0.23 mg/kg/day. There have been 18 minor infections and four potentially serious nonlethal infections in the 27 PTD recipients. One lethal infection occurred 33 months after heart transplantation. The only other fatality was related to metastatic bladder cancer. This lethal infection rate of 3% compares with a rate of 11% in all nondiabetic recipients who have follow-up for 21 months. The 3-year actuarial survival of the PTD group is 75%, which compares favorably with the survival of nondiabetic patients. PTD cannot be predicted by sex, age, or human leukocyte type before transplantation, and it does not significantly increase the incidence of mortality or serious infection.

Coronary Angiography↗