Stroke. 1: A paradigm case in nursing rehabilitation

This is the first of two articles which consider rehabilitation following a stroke. Although stroke is a major cause of morbidity and mortality in the UK there have been relatively few studies describing its long-term effects. Despite relatively good functional recovery, in many cases a number of stroke survivors still experience 'long-term misery'. This article argues for an expanded range of outcomes in stroke rehabilitation and for greater attention to be paid to the psychological needs of stroke survivors and their carers. Areas of deficit in stroke rehabilitation are described, as is the currently poorly developed nursing role.

Cardiac rehabilitation following myocardial infarction

Coronary heart disease is the major cause of death in the UK, but cardiac rehabilitation programmes have tended to develop in an ad hoc and unsystematic way. This article considers some of the deficits in current practice and suggests ways in which nurses can contribute more fully to care in this area. The need for better training and the necessity to develop skills in psychological care are highlighted. The authors also emphasize the importance of giving greater attention to a number of areas such as family involvement, sexuality and gender issues, and community follow-up.

Metabolic effects of troglitazone monotherapy in type 2 diabetes mellitus. A randomized, double-blind, placebo-controlled trial

BACKGROUND

Troglitazone is a new insulin-sensitizing agent used to treat type 2 diabetes mellitus. The mechanism by which troglitazone exerts its effect on systemic glucose metabolism is unknown.

OBJECTIVE

To determine the effects of 6 months of troglitazone monotherapy on glucose metabolism in patients with type 2 diabetes mellitus.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Six general clinical research centers at university hospitals.

PATIENTS

93 patients (mean age, 52 years) with type 2 diabetes mellitus (mean fasting plasma glucose level, 11.2 mmol/L) who were being treated with diet alone or who had discontinued oral antidiabetic medication therapy.

INTERVENTION

Patients were randomly assigned to one of five treatment groups (100, 200, 400, or 600 mg of troglitazone daily or placebo) and had metabolic assessment before and after 6 months of treatment.

MEASUREMENTS

Plasma glucose and insulin profiles during a meal tolerance test; basal hepatic glucose production and insulin-stimulated glucose disposal rate during a hyperinsulinemic-euglycemic clamp procedure.

RESULTS

Troglitazone at 400 and 600 mg/d decreased both fasting (P < 0.001) and postprandial (P = 0.016) plasma glucose levels by approximately 20%. All four troglitazone dosages also decreased fasting (P = 0.012) and postprandial (P < 0.001) triglyceride levels; 600 mg of the drug per day decreased fasting free fatty acid levels (P = 0.018). Plasma insulin levels decreased in the 200-, 400-, and 600-mg/d groups (P < 0.001), and C-peptide levels decreased in all five study groups (P < 0.001). Basal hepatic glucose production was suppressed in the 600-mg/d group compared with the placebo group (P = 0.02). Troglitazone at 400 and 600 mg/d increased glucose disposal rate by approximately 45% above pretreatment levels (P = 0.003). Stepwise regression analysis showed that troglitazone therapy was the strongest predictor of a decrease in fasting (P < 0.001) or postprandial (P = 0.01) glucose levels. Fasting C-peptide level was the next strongest predictor (higher C-peptide level equaled greater glucose-lowering effect).

CONCLUSION

Troglitazone monotherapy decreased fasting and postprandial glucose levels in patients with type 2 diabetes, primarily by augmenting insulin-mediated glucose disposal.

Rehabilitation following spinal injury: the nursing response

Spinal cord injury is one of the most unexpected and devastating of events that typically affects young people, often males. Thus it stands in stark contrast to both multiple sclerosis and arthritis, the conditions considered in the previous two articles of this series. The differences do not end here as spinal injury is relatively stable once the initial phase has passed, whereas both multiple sclerosis and arthritis are progressive. However, despite this variation the literature suggests that rehabilitation in all three conditions raises similar concerns. This article focuses on these concerns and how nurses can respond to them.

Arthritis and rehabilitation: developments in the nurse's role

This article is the third in a series concerned with the nurse's role in rehabilitation dealing with both individuals and their family carers facing the challenges posed by a number of chronic conditions. This article focuses on arthritis. Following the format of earlier articles attention is first turned to patients' experiences of arthritis. This is then followed by consideration of a range of psychosocial interventions. It is suggested that the nurse's role in arthritis care is reasonably well established; however, further developments, particularly in the community, are briefly explored.

Rehabilitation in multiple sclerosis: the potential nursing contribution

This article, the second in a series focusing on aspects of rehabilitation, considers the potential nursing role in relation to multiple sclerosis (MS). It begins with a brief description of the experience of MS as recounted by the individuals affected, which is then contrasted with current interventions which focus primarily on physical aspects of care. A number of areas of potential improvement are outlined, together with suggestions for a more comprehensive nursing role.

Rehabilitation: realizing the potential nursing contribution

This article highlights the present renewed interest in the subject of rehabilitation and describes the nursing role as it is portrayed in the literature. It is argued that the focus of rehabilitation is too narrow, concentrating mainly on the physical aspects of care, and that the nursing contribution is under developed. The article is the first in a series which will subsequently consider rehabilitation in multiple sclerosis, arthritis, spinal injury, myocardial infarction and stroke. The series will conclude with suggestions as to how rehabilitation in general, and nursing in particular, can respond more adequately to the needs of chronically ill and disabled people and their family carers.

Late, intermittent obstruction of a mitral prosthesis by chordal remnants

A 59 year old male was admitted 10 weeks following insertion of a Medtronic Hall mitral prosthesis. He suffered recurrent episodes of electromechanical dissociation (EMD). Transthoracic echocardiography demonstrated that during the times of haemodynamic compromise, the mitral prosthesis was intermittently obstructed. Emergency surgical intervention revealed that chordae tendineae had prolapsed through the lesser orifice, obstructing the valve mechanism. The mitral remnants were excised, and as the valve functioned normally, it was not replaced. Postoperatively, the patient made an uneventful recovery. This case illustrates the Doppler echocardiographic features associated with extrinsic obstruction of a mitral prosthesis, and demonstrates that this unusual complication can be responsible for late valve dysfunction.

Feasibility and applicability of coronary stent implantation with the direct brachial approach: results of a single-center study

Implantation of stents in selected patients improves outcome after coronary angioplasty. Newer antiplatelet regimes limit access site complications associated with stenting by the percutaneous femoral approach, but a substantial proportion of patients will require anticoagulant therapy for concomitant disease or will have peripheral vascular disease that prevents access from the leg. We investigated procedural success rates and outcome in consecutive patients undergoing elective stent implantation in our institution. In 73 patients who were receiving anticoagulation therapy and were stented by a direct approach to the left brachial artery, 98.6% of stents were successfully deployed, with a major vascular access site complication rate of 1.4%. Equipment consumption, procedural success rate, and fluoroscopy time were similar in patients stented by the direct brachial or percutaneous femoral approach. Where the percutaneous femoral approach is precluded or patients are anticoagulated, stent procedures can be successfully performed by the direct brachial approach with a low rate of access site complications, even when large-caliber guiding catheters are required.

2-Cyclopropylindoloquinones and their analogues as bioreductively activated antitumor agents: structure-activity in vitro and efficacy in vivo

A series of 2-cycloalkyl- and 2-alkyl-3-(hydroxymethyl)-1-methylindoloquinones and corresponding carbamates have been synthesized and substituted in the 5-position with a variety of substituted and unsubstituted aziridines. Cytotoxicity against hypoxic cells in vitro was dependent upon the presence of a 5-aziridinyl or a substituted aziridinyl substituent for 3-hydroxymethyl analogues. The activity of 5-methoxy derivatives was dependent upon the presence of a 3-(carbamoyloxy)methyl substituent. Increasing the steric bulk at the 2-position reduced the compounds' effectiveness against hypoxic cells. A 2-cyclopropyl substituent was up to 2 orders of magnitude more effective than a 2-isopropyl substituent, suggesting possible radical ring-opening reactions contributing to toxicity. Nonfused 2-cyclopropylmitosenes were more effective than related fused cyclopropamitosenes reported previously. The reduction potentials of the quinone/semiquinone one-electron couples were in the range -286 to -380 mV. The semiquinone radicals reacted with oxygen with rate constants 2-8 x 10(8) dm3 mol-1 s-1. The involvement of the two-electron reduced hydroquinone in the mediation of cytotoxicity is implicated. The most effective compounds in vitro were the 2-cyclopropyl and 5-(2-methylaziridinyl) derivatives, and of these, 5-(aziridin-1-yl)-2-cyclopropyl-3-(hydroxymethyl)-1-methylindole-4 ,7-dione (21) and 3-(hydroxymethyl)-5-(2-methylaziridin-1-yl)-1,2-dimethylindole+ ++-4,7-dione (54) were evaluated in vivo. Both compounds showed antitumor activity both as single agents and in combination with radiation, with some substantial improvements over EO9 (3) at maximum tolerated doses and as single agents against the RIF-1 tumor model and comparable efficacy in the KHT tumor model.

The correction of autonomic dysfunction in cirrhosis by captopril

BACKGROUND/AIMS

Vagal dysfunction is reported in about 70% of patients with cirrhosis, irrespective of aetiology, as detected by cardiovascular reflex tests. We have previously shown that RR-variability on 24-h ECG is a more sensitive marker of vagal dysfunction in cirrhosis. Angiotensin II inhibits vagal function in animals, and it is elevated in cirrhosis and may be the cause of the vagal dysfunction. Our aim was to observe the effect of captopril on vagal dysfunction in cirrhosis.

METHODS

Eight patients with cirrhosis (biopsy proven, male two, female six, mean age 54.25) had 24-h ECG RR-variability performed. They then received captopril 25 mg t.d.s. for 48 h. The 24-h ECG was repeated on therapy.

RESULTS

Mean blood pressure remained unchanged: baseline 89.8 +/- 4.8 mmHg (mean +/- sem) versus 91.8 +/- 5.9 mmHg, p = not significant. Median baseline RR-variability was 791 (range 18-5344) counts/24 h and increased in all but one patient, with captopril, to 1548 (56-4824) p = 0.008. Three increased into the normal range.

CONCLUSION

The vagal dysfunction of cirrhosis is caused by neuromodulation by angiotensin II and is not due to a neuropathy.

Self-directed and student-centred learning in nurse education: 2

Based on a study of student nurses' expectations at the start of their Project 2000 training, this article, the second of two, argues for the need to develop a new approach to self-directed learning. Termed the cooperative model, it places emphasis on tutors providing initial direction and leadership so that students can gradually develop the skills needed to become self-directed. This requires the use of pedagogical approaches which recognize the value of didactic as well as experiential teaching strategies. The characteristics of the cooperative model, which is located within the continuum of self-directed learning suggested by D'A Slevin and Lavery (1991), are outlined.

Preservation of autonomic function following successful reperfusion with streptokinase within 12 hours of the onset of acute myocardial infarction

Successful reperfusion following thrombolysis results in increased heart rate variability in the first 24 hours after administration. Preservation of autonomic function may contribute to improved prognosis when coronary artery patency is restored with intravenous thrombolysis.

Self-directed and student-centred learning in nurse education: 1

This article, the first of two, considers the factors precipitating the widespread adoption of self-directed and student-centered learning in nurse education. It argues that these concepts have been accepted in a relatively uncritical fashion and that the theoretical rationale for their use has yet to be fully tested empirically. The results of a study of the expectations of Project 2000 students suggest that adult learners may not necessarily want the freedom afforded by self-directed approaches, but may prefer a more structural and ordered model.

Maryland Emergency Medical Services and Shock Trauma Centre

The author spent one year working as an attending Anaesthesiologist at the Shock Trauma Center in Baltimore. The Maryland trauma system is, in the author's opinion, one of the best in the United States and this article will outline the Maryland EMS (Emergency Medical Service) but with specific emphasis on the Shock Trauma Center in Baltimore.

Entry to care: positive choice or fait accompli? developing a more proactive nursing response to the needs of older people and their carers

A range of issues surrounding admission to either residential or nursing home care are considered from the perspectives of older people and their family carers. Drawing on the literature and a number of studies conducted by the authors, the processes and perceptions that shape and influence admission to care are identified. On the basis of the interaction of these factors a four-stage typology of admission is suggested: the positive choice, the rationalized alternative, the discredited option, and the fait accompli. The characteristics of each admission type are discussed and the implications for professionals, particularly nurses, working with older people and their carers are addressed.

Tidal volumes which are perceived to be adequate for resuscitation

Observers trained in basic life support assessed chest rise in 34 patients who were anaesthetised and paralysed and whose lungs were being mechanically ventilated prior to routine surgery. Making 67 independent assessments, the observers indicated the tidal volume that they considered produced adequate chest rise for resuscitation. The mean tidal volume perceived to be adequate was 384 ml with 95% confidence limits of 362-406 ml. The perceived volumes correlated with the Body Mass Index. Guidelines by various authorities recommend that tidal volumes sufficient to make the chest rise normally should be used during resuscitation. The volumes perceived as adequate by the observers are much lower than the numerical values recommended by the American Heart Association (800-1200 ml). High tidal volumes are associated with an increased risk of gastric regurgitation in patients with an unprotected airway, CO2 delivery to the lungs is likely to be low during cardiac arrest obviating the need for high tidal volumes. In the light of present knowledge and the findings in this study, we would recommend that resuscitation training manikins are recalibrated to indicate satisfactory ventilation at tidal volumes of 400-600 ml. These volumes should reduce the risk of gastric inflation and permit more chest compressions to be carried out in a minute because the ventilation fraction of the CPR sequence is shorter. Adequate CO2 elimination should still be assured.

Measurement of parasympathetic activity from 24-hour ambulatory electrocardiograms and its reproducibility and sensitivity in normal subjects, patients with symptomatic myocardial ischemia, and patients with diabetes mellitus

The parasympathetic nervous system plays a major role in the pathophysiology of many cardiovascular disease, particularly in modulating myocardial electrical stability. Measurements of heart rate variability have been widely used to assess parasympathetic activity. The reproducibility of measurements obtained from 24-hour ambulatory electrocardiograms has not been well documented. We have developed a technique for measuring parasympathetic activity from clinical quality 24-hour ambulatory electrocardiograms by counting beat-to-beat increases in RR interval that are > 50 ms. To determine the reproducibility and sensitivity of our technique, we analyzed repeated 24-hour electrocardiograms of 173 subjects (19 normal subjects, 67 patients with ischemic heart disease, and 87 diabetics) followed up over periods of 2 to 16 weeks. In all subject groups, mean values for repeated measurements were virtually identical. Measurements were stable in all 3 groups throughout the course of the study, as assessed by intraclass correlation coefficients. This technique is sensitive enough to detect relatively small changes in parasympathetic activity in subjects, as demonstrated by the calculated Bland and Altman coefficients of repeatability. Reproducibility and sensitivity of our technique are particularly good in normal subjects and in patients with ischemic heart disease. The results obtained with this technique imply that other related measurements of parasympathetic activity will show similar excellent short- and long-term reproducibility and sensitivity.

Stability of Hematological Parameters in Woodland Caribou (Rangifer tarandus caribou) Blood Stored at 4°C

Eighteen free-ranging female woodland caribou were captured in northern Alberta in January and February 1993. Blood was collected into ethylenediaminetetraacetate (EDTA) tubes which were packaged in coolers containing ice packs, and transported to the laboratory where they arrived within 48 hrs of collection. Complete blood counts (CBC) were performed on five consecutive days to assess the stability of hematological parameters. Average values of hematocrit (HCT), mean cell hemoglobin (MCH), mean cell volume (MCV), red cell distribution width (P-J3W), white blood cell count (WBC), and red blood cell count (RJ3C) remained stable with no statistically significant changes occurring during 5 days of post-collection storage at 4&deg;C. Mean PvBC values exhibited significant differences (p&lt;0.05) between geographic locations. Mean platelet volume (MPV) increased significantly (p&lt;0.001) with storage time, while platelet (PLT) values decreased (p&lt;0.001) over time and were significantly different (p&lt;0.01) between locations. For optimal hematological results, it is recommended that sample analysis be performed within 24 hours of blood collection; however, if caribou blood samples are properly stored at 4&deg;C, useful information may be obtained from stable parameters up to 5 days following collection.

Maintaining nurses' job satisfaction and morale

In this article those factors which influence the job satisfaction and morale of nurses are considered. It is suggested that action is needed if the profession is to continue to grow and develop.

Busy doing nothing: activity and interaction levels amongst differing populations of elderly patients

This paper considers the activity and interaction levels amongst three differing populations of elderly patients (long-stay, short-stay and respite). It begins with a consideration of the literature on staff-patient interactions in care environments for elderly patients, highlighting the virtual absence of preplanned, purposeful activity. Data are then presented which suggest that, despite the emphasis nurses place on communicating with their patients, many patients continue to spend most of their time inactive. It is suggested that if the quality of care elderly patients receive is to improve, nursing staff must see the provision of activity as an integral part of their role and function.

Heart failure: an old problem

Heart failure is an increasingly common problem in the UK, particularly in older patients. This article reviews the available information is available on heart failure in the older population, and provides clinically useful guidelines on the investigation and treatment of patients with this condition.

Zeolite A inhibits osteoclast-mediated bone resorption in vitro

The effects of Zeolite A on bone resorbing activity of highly purified avian osteoclasts were analyzed. The present study demonstrates that when 100 micrograms/ml of acid-treated Zeolite A is added to the media the number of pits per osteoclast is reduced 3-fold at 24 h after treatment. Secreted cathepsin B enzyme activity was also reduced 3-fold. A similar reduction in pit number per osteoclast was measured following 48 h of treatment with Zeolite A but there appeared to be less reduction of cathepsin B enzyme activity. The effects on pit number and cathepsin B protein activity were Zeolite dose dependent. The structure of the compound seemed to be responsible for the effects measured since compounds used to represent constituents of Zeolite A (silicon dioxide and aluminum chloride) failed to inhibit bone resorption or reduce the level of secreted cathepsin B enzyme activity. Thus the molecular architecture of Zeolite A or a derivative thereof appears to be important. In conclusion, the data indicate that Zeolite A can inhibit bone resorption. Together with previous data on osteoblasts, this might suggest a potential positive activity of intact Zeolite A or a partial substructure of Zeolite A on bone turnover.

Exercise-induced left ventricular dysfunction in alcoholic and non-alcoholic cirrhosis

BACKGROUND/AIMS

Autonomic and cardiac dysfunction have been reported in patients with cirrhosis. We studied left ventricular and autonomic function in 20 patients with both alcoholic and non-alcoholic cirrhosis.

METHODS

Autonomic function was assessed by a standard battery of cardiovascular reflex tests. Supine exercise radionuclide ventriculography was used to assess the cardiac response to exercise.

RESULTS

Exercise capacity was reduced in all patients in association with marked chronotropic incompetence (peak heart rates 120.5 +/- 6 bpm). Unlike normal subjects there was no increase in left ventricular ejection fraction on exercise. Stroke volume increased by 23 +/- 6%, mediated by an increase in end-diastolic.volume of > 20%. Cardiac output was subnormal at maximal exercise, increasing by only 96 +/- 14% and 97 +/- 11% in alcoholic and non-alcoholic groups respectively. The majority (83%) of our patients had autonomic reflex abnormalities.

CONCLUSIONS

Patients with cirrhosis of alcohol and non-alcohol related aetiologies have significantly impaired cardiovascular responses to exercise, which are similar to those of a denervated heart. This may have important clinical implications for the ability of these patients to withstand cardiovascular stress.

Continuing professional education: identifying the characteristics of an effective system

The need for a functioning system of continuing professional education (CPE) in nursing, midwifery and health visiting has received increased attention in recent years. However, whilst the literature describes a number of benefits, detailed empirical studies have been limited. There is, in particular, a dearth of information on nurses' perceptions of the important components of a CPE programme. Using the results of a recent evaluation of the Welsh National Board's Framework for Continuing Education, this paper highlights a number of key issues identified by practitioners, educators and managers throughout Wales. Using a structure-process-outcome model, attention is focused on the outcomes of CPE and the structure and process variables which facilitate or inhibit success. The results indicate a strong commitment to the principles of CPE and identify a complex range of perceived benefits. Potential barriers inhibiting both the uptake of CPE and the achievement of subsequent change are discussed and the need to create an equitable, well-resourced system is stressed.

Responding to the challenge of chronic illness

The management of chronic illnesses represents a major health challenge with interventions still being dominated by approaches that are more appropriate to acute conditions. Nurses have a key role to play in meeting the health needs of people with chronic illnesses and yet place little value on this type of care. This article reviews the Corbin and Strauss model of nursing which has proved effective in the management of a wide range of chronic illnesses.

Changes in atrial natriuretic peptide and plasma renin activity following changes in right atrial pressure in patients with chronic renal failure

Since it was first discovered in the early 1980s, the role of atrial natriuretic peptide (ANP) in the control of fluid and electrolyte balance and blood pressure has been extensively studied in both health and disease. We report here a study of ANP and its relationship to corresponding changes in right atrial pressure (RAP) in patients with chronic renal failure (CRF) on haemodialysis compared to healthy controls. Although there was a positive correlation between RAP and ANP in both groups, the changes in ANP following changes in RAP between the two groups were not statistically significant. A unique observation was the response of RAP to changes in posture, with RAP falling significantly as expected in healthy controls in contrast to the exceptional absence of a significant fall in patients with CRF. Healthy controls demonstrated appropriate postural changes in plasma renin activity (PRA) despite marked suppression of PRA levels due to salt loading, in complete contrast to patients with CRF who, despite chronic fluid overload and elevated levels of ANP, continued to have grossly elevated PRA levels that failed to change significantly in response to changes in posture.

Long hours, little thanks: valuing the role of nurse educators

A recently published survey of the use of time by full-time academic and related staff in UK universities (Court, 1994) highlighted concerns about the workload pressures and competing demands faced by staff in academic institutions. Administrative tasks, particularly those associated with the recurrent research and teaching assessment exercises, now constitute an increasingly large proportion of the working week, accounting for a third of all duties.

Comparison of the separation of proteins by sodium dodecyl sulfate-slab gel electrophoresis and capillary sodium dodecyl sulfate-gel electrophoresis

Capillary sodium dodecyl sulfate-gel electrophoresis, a one-dimensional version of the well-established planar analytical method of SDS-polyacrylamide gel electrophoresis, has proven a powerful new microanalytical method for the separation of protein molecules according to their size. In this paper the planar SDS-PAGE and the capillary SDS-gel electrophoresis of different proteins are compared with respect to performance, precision, and efficiency. Molecular weight versus migration distance and migration time curves for 65 proteins, running from 14,200 to 205,000 Da, are given for both methods.

Autonomic function in cirrhosis assessed by cardiovascular reflex tests and 24-hour heart rate variability

OBJECTIVES

To assess the prevalence of autonomic dysfunction in cirrhosis and to observe the effect of disease severity on autonomic dysfunction.

METHODS

Seventy patients with cirrhosis (Child's class A, 42; Child's class B, 10; and Child's class C, 15) (45 alcoholic, 15 primary biliary cirrhosis, five chronic active hepatitis, and eight idiopathic) underwent standard cardiovascular reflex tests. In addition, in 40 patients, 24-h ECG RR variability tests were performed to detect autonomic dysfunction.

RESULTS

Forty-two of 70 (60%) patients had abnormalities of cardiovascular reflex function of varying severity, whereas 24 of 34 (70%) had 24-h RR counts with the 95% age-related tolerance. The prevalence of abnormality increased with increasing severity of liver disease but not with different etiologies.

CONCLUSION

Irrespective of etiology, there is a high prevalence of autonomic dysfunction in cirrhosis, and it is related to disease severity: the mechanism is unknown.

Cardiac effects of sodium stibogluconate: myocardial, electrophysiological and biochemical studies

The pentavalent antimonial sodium stibogluconate is the mainstay of anti-leishmanial therapy. Sodium stibogluconate is less cardiotoxic than antimony and the trivalent derivatives, but has been associated with dose-related electrocardiographic changes. The effect of the currently-used regimen of sodium stibogluconate (20 mg/kg/day for 20 days) on cardiac function is uncertain. We studied 12 soldiers, mean age 24 years, with proven cutaneous leishmaniasis treated with this regimen. There were no significant changes in echocardiographic indices of left ventricular systolic or diastolic function during treatment. Indices of myocardial electrical stability (heart-rate variability and episodes of overt supraventricular and ventricular arrhythmias) were unchanged, but there was a reversible decrease in T-wave amplitude during treatment. Systolic and diastolic blood pressure fell and the heart rate increased during treatment. This regimen of sodium stibogluconate does not measurably impair left ventricular systolic or diastolic function. Minor T-wave changes occur during treatment, but there is no increase in arrhythmia frequency or change in heart-rate variability. In most young fit patients, this regimen has no cardiac side-effects. However, idiosyncratic reactions cannot be excluded, and patients with malnutrition, impaired renal function or pre-existing heart disease may be more sensitive to any cardiotoxic properties of sodium stibogluconate.

Cardiac parasympathetic activity in severe uncomplicated coronary artery disease

BACKGROUND

Previous studies have suggested that coronary artery disease is independently associated with reduced cardiac parasympathetic activity, and that this is important in its pathophysiology. These studies included many patients with complications that might be responsible for the reported autonomic abnormalities.

OBJECTIVE

To measure cardiac parasympathetic activity in patients with uncomplicated coronary artery disease.

PATIENTS AND METHODS

44 patients of mean (SD) age 56 (8) with severe uncomplicated coronary artery disease (symptoms uncontrolled on maximal medical treatment; > 70% coronary stenosis at angiography; normal ejection fraction; no evidence of previous infarction, diabetes, or hypertension). Heart rate variability was measured from 24 hour ambulatory electrocardiograms by counting the number of times successive RR intervals exceeded the preceding RR interval by > 50 ms, a previously validated sensitive and specific index of cardiac parasympathetic activity.

RESULTS

Mean (range) of counts were: waking 112 (range 6-501)/h, sleeping 198 (0-812)/h, and total 3912 (151-14 454)/24 h. These mean results were unremarkable, and < 10% of patients fell below the lower 95% confidence interval for waking, sleeping, or total 24 hour counts in normal people. There was no relation between the severity of coronary artery disease or the use of concurrent antianginal drug treatment and cardiac parasympathetic activity.

CONCLUSION

In contrast with previous reports no evidence of a specific independent association between coronary artery disease and reduced cardiac parasympathetic activity was found. The results of previous studies may reflect the inclusion of patients with complications and not the direct effect of coronary artery disease itself.

Radiolytic and photochemical reduction of the hypoxic cytotoxin 1,2-dihydro-8-(4-methylpiperazinyl)-4-phenylimidazo [1,2-a] pyrido [3,2-e] pyrazine 5-oxide (RB90740) and a potential mechanism for hypoxia-selective toxicity

PURPOSE

To study the reduction of RB90740 (1), a fused pyrazine mono-N-oxide that has an oxic:hypoxic cytotoxicity ratio of > 10 in a range of murine and human tumor cells in vitro.

METHODS AND MATERIALS

Reduction of 1 has been initiated radiolytically and photochemically in aqueous solution and the products isolated and characterized by high performance liquid chromatography (HPLC).

RESULTS

Radiolytic reduction of 1 leads to the formation of the 2-electron reduced product, 2. The stoichiometry of the reduction is pH dependent, increasing from 1 to 2 with increasing pH, but independent of the presence of formate or 2-methyl 2-propanol in the reduction mixture. A dimerization product, 3, is also found, which is produced in greater yields at lower pH (< 6). Photochemical reduction of 1 to 2 was also found to be facile. Photolysis of 1 also leads to a deoxyribonucleic acid cleavage reaction.

CONCLUSION

Since 2 is not cytotoxic towards hypoxic cells at concentrations at which 1 is toxic, a probable candidate as the cytotoxic species under hypoxic conditions is the 1-electron reduced intermediate species.

Information technology factors in transferability of knowledge based systems in medicine

The history of knowledge based systems in medicine has been that they are generally very localised, serving a special need in a single setting. Very few have proven to be capable of transfer to a distant environment. With the advent of tele-medical services and the associated transfer of data and knowledge in such services, the ability of medical KBS to transfer will be crucial to the success of tele-medical services. Differences in knowledge acquisition methods, knowledge representation techniques and in the epidemiological composition of training databases may influence viable transfer of knowledge based systems. Through experiments we demonstrate how rule-based systems may impose inflexible demands on data, how different knowledge acquisition techniques acquire different aspects of knowledge, though trained on a common training database, and how different knowledge acquisition techniques show varying degrees of robustness to slight changes in training databases.

Delayed onset of insulin activation of the insulin receptor kinase in vivo in human skeletal muscle

During the infusion of insulin in vivo, the rate of activation of glucose disposal lags significantly behind the rate of increase in serum insulin levels. To determine whether this delay was related to transcapillary transport of insulin, we determined increments in serum insulin levels, glucose disposal rates (GDR), and insulin receptor (IR) kinase activity measured during continuous infusions of insulin (40 and 120 mU.m-2.min-1) administered to 8 nondiabetic males; similar studies were done at 1,200.m-2.min-1 in 2 of the subjects. Half-maximal insulin levels were achieved at a mean of 4.9 and 7.2 min during the 40 and 120 mU.m-2.min-1 clamps, respectively, with corresponding half-maximal GDR stimulation at a mean of 59 and 47 min. Unlike the rise in insulin levels, IR kinase activation was much slower with half-maximal activity occurring at approximately 40-60 min in the 2 clamps. Thus, the rise in serum insulin levels in each clamp was much faster than the increment in either kinase activity or glucose disposal. Insulin infusion increased both IR kinase and GDR maximally approximately 10-fold, with half-maximal stimulation at approximately 3,600 and approximately 700 pM, indicating spare kinase for glucose disposal. These results demonstrate that the delay in stimulation of glucose disposal by insulin is related to a rate-limiting step between the intravascular space and the cell-surface of skeletal muscle. This may involve delayed transendothelial transport of insulin.

Clinical utility of an international thyroid database

Assessment of thyroid function is prone to errors from several sources. Confusion is most often due to inappropriate use of tests, especially in patients with acute non-thyroid illness. With these problems in mind we have designed an international prospective thyroid database in three countries, which registers clinical and laboratory data on new patients with suspected thyroid disease. An additional aim was to assess the use of a computerised decision support tool to interpret thyroid data. The database permits rapid access to temporal trends in thyroid tests, which is useful in monitoring therapy and in follow up for hyperthyroidism. Marked contrasts in local clinical practices have highlighted the challenge in providing a valid decision tool to serve all clinical needs. Experience with multi-centre databases such as this hold promise in the drive to coordinate the disciplines of laboratory analysis and clinical decision making.

Heterocyclic mono-N-oxides with potential applications as bioreductive anti-tumour drugs: Part 1. 8-Alkylamino-substituted phenylimidazo [1,2-a] quinoxalines

A series of imidazo [1,2-a] quinoxaline mono-N-oxides and their 6- and 9-aza analogues have been substituted in the 8-position with a variety of secondary and tertiary amines, and the compounds evaluated as bioreductively activated cytotoxins. Cytotoxic action against hypoxic cells in vitro was critically dependent upon the structural nature of the 8-substituent and its basicity, with little dependence upon reduction potential. 1,2-Dihydro-8-(4-methylpiperazin-1-yl)-4-phenylimidazo [1,2-a] pyrido [3,2-e] pyrazine 5-oxide (11) had differential hypoxic:oxic toxicity of 15.3 and some novel analogues had differential hypoxic:oxic toxicities of 7.5-17. Other related compounds with either substituted or unsubstituted 8-piperazinyl substituents, or certain straight-chain aminoalkyl substituents, show comparable activity in vitro. Less basic 8-substituents abolished activity, although the 8-morpholinyl derivatives (7 and 8) had differential hypoxic:oxic toxicities of 3-4. Substitution of the 4-phenyl ring with an electron-withdrawing group (F) improved hypoxic potency, but only with a small effect on hypoxic:oxic toxicity, whereas an electron-donating substituent (MeO) reduced hypoxic potency. Perhaps significantly, the 8-unsubstituted analogue 3 was 6-fold less potent, but had comparable differential cytotoxicity in vitro. The most effective novel hypoxia-selective cytotoxins synthesized were the bifunctional 2-nitro-imidazole derivative 1,2-dihydro-8-((4-(3-(2-nitro-1-imidazoyl)-1-hydroxypropyl)- piperazin-1-yl))-4-phenylimidazo [1,2-a] quinoxaline 5-oxide bishydrochloride (37) and its 9-aza analogue 38. These compounds also exhibited the lowest aerobic toxicities in vitro of the new compounds.

Can nurses take an accurate blood pressure?

It is over 20 years since the Briggs (1971) report extolled the virtues of nursing becoming a research-based profession. However, despite progress having been made towards achieving a research base, studies all too rarely inform nursing practice. This article offers a number of explanations for this failure and demonstrates the benefits of research by examining nurses' knowledge of the factors that are important in taking an accurate blood pressure reading.

Protein turnover in two kangaroo sub-species (Macropus robustus robustus and M. r. erubescens) from divergent habitats and the sympatric feral goat (Capra hircus)

1. Whole-body protein turnover was measured by a single-injection [15N]glycine method in the euro (Macropus robustus erubescens), wallaroo (M. r. robustus) and goat (Capra hircus). 2. Dietary nitrogen (N) intake was greater (P < 0.05) in the goat (1.17 g N/kg 0.75 x day) than in the kangaroo sub-species and greater (P < 0.05) in the wallaroo (1.07 g N/kg 0.75 x day) than in the euro (0.93 g N/kg 0.75 x day). similar (0.29-0.34 g N/kg 0.75 x day) among the species. 3. Crude protein (CP) turnover was similar in the euro (14.8 g CP/kg 0.75 x day) and goat (13.8 g CP/kg 0.75 x day) and less (P < 0.05) in the wallaroo (10.4 g CP/kg 0.75 x day).

Supraventricular tachycardia, right atrial pressure, atrial natriuretic peptide and polyuria--a necessary sequence?

The release of atrial natriuretic peptide (ANP) may be stimulated by tachycardia and the evidence from human studies suggests that this is mediated by a rise in atrial pressure. However, animal experiments suggest that tachycardia can by itself increase ANP levels without increasing right atrial pressure (RAP). We report here the case of a healthy volunteer who had supraventricular tachycardia (SVT) whilst participating in a study evaluating the relationship between changes in RAP and changes in ANP. The ANP levels rose following the SVT but there was no rise in RAP, suggesting that heart rate can modulate ANP levels without changes in RAP as has been shown in animal experiments.