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G Hart

Publications and source records attributed to G Hart.

At least 91 records · Page 5Linked to original sources
PubMed1996

Transient outward current in catecholamine-induced cardiac hypertrophy in the rat.

We have demonstrated that a daily injection of isoproterenol (5 mg/kg ip) for 7 days induces a 30% increment in heart weight-to-body weight ratio and prolongs the action potential duration (APD) in male Wistar rats. The underlying mechanism of the prolonged APD was investigated in this model of hypertrophy by measuring the transient outward potassium current (Ito) in left ventricular myocytes of the rat with whole cell voltage-clamp techniques. Cell membrane capacitance was increased by 39%: 122 +/- 3 (n = 23) and 171 +/- 5 (SE) pF (n = 20) in control and hypertrophy, respectively (P < 0.001). Ito was evoked in sodium-free solutions containing 0.5 mM Ca2+ and 2 mM Co2+ by step depolarizations from a holding potential of -80 mV. The amplitude of the 4-aminopyridine-sensitive Ito (at 70 mV) was reduced by 28% in hypertrophy: 3.2 +/- 0.3 (n = 23) and 2.3 +/- 0.4 (SE) nA (n = 20) in control and hypertrophy, respectively (P < 0.05). When normalized for cell capacitance, the reduction was much larger: 26.4 +/- 2.5 and 13.1 +/- 1.8 pA/pF in control and hypertrophy, respectively (P < 0.001). The voltage dependence of Ito was similar in both cell types. No change was observed in the steady-state activation and inactivation kinetics in the two groups, nor was there a change in the time dependence of inactivation. The recovery from inactivation of Ito when fitted with a monoexponential function was not changed significantly in hypertrophy: time constants = 8.2 +/- 0.4 (n = 13) and 8.3 +/- 0.3 ms (n = 12) in control and hypertrophy, respectively. These results show that Ito density is decreased in catecholamine-induced cardiac hypertrophy, but current kinetics are not affected. The reduced Ito density may underlie the prolongation of APD in this model of hypertrophy.

4-Aminopyridine↗
PubMed1996

Transporting.

Explore the source record for details and available documents.

Ambulances↗
PubMed1995

The clinical learning environment: nurses' perceptions of professional development in clinical settings.

Although the complexity of the working environment of Registered Nurses has been acknowledged, the relationship between the social context of work and perceptions of professional development have not been systematically studied. This research was designed to identify and explore the attributes of effective learning environments in clinical settings. Following an initial exploratory study of perceptions and experiences of registered and student nurses, a conceptual framework was developed and tested. The findings of the study ware based on responses to a questionnaire (n = 516) which was developed as a tool for assessing organisational and social factors associated with perceived professional development in clinical settings. There was a significant and positive correlation between professional development and six independent variables: Autonomy and Recognition, Role Clarity, Job Satisfaction, Quality of Supervision, Peer Support and Opportunities for Learning. These variables accounted for almost 40% of the variance in perceived professional development. There were differences between hospitals and wards on most of the independent variables suggesting that some wards and institutions are more conducive to learning than others. The implications of the findings in terms of further research and practice are discussed.

Attitude of Health Personnel↗
PubMed1995

Gay men's accounts of unsafe sex.

This paper provides a qualitative analysis of the explanations given by a sample of 78 gay men in England of the most recent occasion on which they engaged in anal intercourse without a condom. Explanations are analysed and interpreted from the sociological perspective of 'accounts': that is, they are not viewed as exact descriptions of the 'real' motives for behaviour but are seen as a powerful resource that can illuminate the knowledge, assumptions and values that inform behaviour. Four distinct types of accounts were identified from the men's descriptions of the circumstances and motivations surrounding their most recent unsafe sexual encounter. These related to: (i) their emotional needs and drives; (ii) the calculus of risk; (iii) issues of trust; and (iv) lapses of control. Each of these types of account is described and the implications of the typology are considered, both for our understanding of the meanings, considerations and constraints surrounding high-risk sexual behaviour and for developing more relevant health education interventions.

Adolescent↗
PubMed1995

Can academic medical centers compete in a managed care system?

The authors review characteristics of successful group practices, health maintenance organizations, and integrated service networks and then identify the critical actions that academic medical centers must take in order to compete with such service-oriented community providers. Centers must (1) form the clinical faculty into a competitive medical group that offers more price-competitive and user-friendly services; (2) restructure clinical training to be more relevant to the emerging practice situation; and (3) clearly delineate funding streams and identify the cross-subsidies taking place in the teaching, research, and patient care enterprises. These changes have the potential to strengthen clinical training and improve the financial positions of both the faculty and the university hospitals. The authors maintain that centers can make these and other necessary changes while still providing high-quality care and maintaining their educational and research functions; they cite organizations that have succeeded in these ways. However, as with all complex, large-scale organizations, public and private alike, the major factor limiting centers' ability to make the organizational changes required to successfully compete in the new health care environment is the lack of political will. It will be very difficult for academic medical centers to unite their powerful internal interest groups and take action without first experiencing a rather severe external jolt. The challenge for the leaders of academic medical centers is to prepare for the managed care jolt so that they can then guide their institutions to a new, more competitive position.

Academic Medical Centers↗
PubMed1995

Living with haemophilia and HIV/AIDS: support and coping.

This paper describes sources and types of support, appraisal of support, and use of social support as a strategy for coping with Acquired Immune Deficiency Syndrome (AIDS)-related stresses. Thirty people with haemophilia, 23 family caregivers and 17 bereaved relatives participated. The study was conducted in two stages: individual interviews and mailed questionnaires. The key coping strategies used were 'normalizing personal relationships' and 'seeking informational support'. Informational support was provided by health professionals and practical aid by relatives. Respondents reported insensitivity, prejudice and avoidance from others. Participants needed peers for emotional and affirmational support, and professionals for informational support. The preferred intervention was support groups, co-led by professionals and peers.

Adaptation, Psychological↗
PubMed1995

Clinical nurse specialist: walking the wire.

Considered by many to be the panacea for all nursing's problems, the clinical nurse specialist (CNS) has only recently gained widespread recognition as a legitimate role in Australia. The CNS is the equivalent in other states and territories of the clinical nurse consultant, the charge nurse or the nurse unit manager. Implementation of the role has been complicated by inadequately delineated role functions, unrealistic expectations and limited recognition of clinical expertise. Using both quantitative and qualitative exploratory techniques it was found that three critical themes impinged in a negative way on the effectiveness of the CNS. These were role ambiguity, role overload and the 'paradox of power'. Maintaining clinical expertise in the practice setting is essential for high quality cost effective and autonomous nursing care and this can be provided through the effective implementation of the CNS role.

Attitude of Health Personnel↗
PubMed1995

In vitro oxidative damage to tissue-type plasminogen activator: a selective modification of the biological functions.

OBJECTIVE: Tissue-type plasminogen activator (t-PA) is an important component of the blood fibrinolytic system responsible for thrombus dissolution. It is often required to function under oxidative stress, and exogenous t-PA is used clinically in the treatment of acute myocardial infarction (AMI). The aim of this study was to examine alterations in the residual activity of t-PA pre-treated with certain oxidants. METHODS: Recombinant t-PA (rt-PA) and native t-PA (nt-PA) were pre-treated with freshly generated hypochlorous acid (HOCl) and chloramine T at varying concentrations. The amidolytic activity, the plasminogenolytic activity and the fibrin-binding affinity were then examined using chromogenic assays based on S-2288 and S-2251. RESULTS: The amidolytic activity of t-PA was surprisingly found to be rather sensitive (IC50 1 and 12 mumol/1, respectively), and the plasminogenolytic activity rather resistant to pre-treatment with HOCl and chloramine T. The fibrin binding study of treated t-PA revealed substantial loss of binding to CNBr-digested fibrinogen (FDP-CNBr). The velocity of t-PA in reaction with plasminogen remained the same as non-treated t-PA. The possible mechanisms of this asymmetrical oxidative modification of the biological functions are also discussed. CONCLUSIONS: (1) The catalytic activity of t-PA and the binding affinity for its large-molecule substrate plasminogen, rather than the small-molecule substrate S-2288, are highly resistant to oxidative damage; (2) the fibrin-binding affinity of t-PA can be selectively and asymmetrically damaged by exposure to these oxidants. Thus it is possible that the characteristic advantage of thrombus selectivity of t-PA in both spontaneous thrombolysis and thrombolytic therapy may be diluted in circumstances where toxic and reactive oxidants exist.

Amino Acid Sequence↗
PubMed1995

Sexually transmitted diseases in Australia: a decade of change. Epidemiology and surveillance.

Survival data in the last decade for sexually transmitted diseases (STDs) other than human immunodeficiency virus (HIV) are uneven across the states/territories. The incidence of gonorrhoea decreased by more than 80%, but at different times in different patient groups, different states, and different anatomical sites. There was a resurgence of rectal gonorrhoea in homosexual men in 1989-1991. Resistance to penicillin steadily increased, and partial resistance to quinolones has emerged. There was a marked decline in syphilis in most states. Lymphogranuloma venereum is rare, and chancroid seen mostly in returning travellers from Southeast Asia; however, hundreds of cases of donovanosis are seen annually among rural Aborigines. The prevalence of genital infections with Chlamydia trachomatis remained stable at 2.5%-14% in STD clinics, and 5% in family planning clinics. The numbers of cases of clinical genital herpes and warts are mostly unavailable. However, specific serology for herpes simplex virus type 2 (HSV-2) indicates that 14% of antenatal clinic patients, and 40%-60% of STD patients have been exposed. Pap smears have detected the presence of human papilloma virus (HPV) in 14%-40% of various clinic populations. Exposure to hepatitis B in the non-Aboriginal population decreased markedly. Hepatitis C infection occurred in a high percentage of injecting drug users; the evidence for sexual transmission is not strong. An epidemic of hepatitis A infection occurred in male homosexuals in 1989-1991. Changes in the Australian sex industry resulted in marked improvements in the sexual health of local (but not international) sex workers. The high levels of STDs in Aboriginal communities continues to cause concern.

Australia↗
PubMed1994

Nurses' responses to patient anger: from disconnecting to connecting.

Caring for angry patients can be a threatening experience. Grounded theory research was used to explore female nurses' reactions and feelings as the recipients of patient anger. The data were collected by interviewing nine female registered nurses in two hospitals in south-western Nova Scotia. The participants were asked to discuss their feelings and responses to an intense encounter with an angry patient. Anger was defined as a multi-dimensional concept with negative cogitations. The concept of self-efficacy emerged as the major area of concern for the participants. The findings suggest that when the threat to self was high, nurses managed anger situations by disconnecting from the angry patient. Low or controllable threats were generally managed by connecting with the angry patient.

Adaptation, Psychological↗
PubMed1994

Regular partners and risky behaviour: why do gay men have unprotected intercourse?

Studies in both the UK and the USA continue to show that gay and bisexual men put themselves at risk of exposure to HIV through unprotected intercourse, most often with regular partners. As part of a larger study of homosexually active men, 310 men who had had unprotected anal intercourse with a man in the previous year were asked to describe the last occasion on which this had happened. The majority of men had had unprotected intercourse with a regular partner and did not perceived it as risky, although most did not know the HIV status of their partner. Regular and non-regular partners were perceived differently. Men were more likely to be emotionally involved in regular partners and to perceive unprotected penetrative sex with a regular partner as not risky. Future health education initiatives must take into account men's emotional involvement in regular partners and their perception of unprotected intercourse with such partners as not risky.

Adolescent↗
PubMed1994

QT interval dispersion in chronic heart failure and left ventricular hypertrophy: relation to autonomic nervous system and Holter tape abnormalities.

OBJECTIVE: To study QT dispersion in left ventricular hypertrophy and chronic heart failure and to determine the relation to ventricular arrhythmias. SETTING: Investigational laboratory of a tertiary referral centre. STUDY DESIGN: Patients with left ventricular hypertrophy and normal systolic function (n = 14) and patients with chronic heart failure (n = 18) were matched with controls (n = 17). The QT dispersion was examined in relation to abnormalities in resting mechanical and autonomic function and to the findings of 24 hour Holter monitoring. MAIN OUTCOME MEASURES: QT dispersion is the difference between the maximum and the minimum QT values from the 12 lead electrocardiogram. Mean(SD) QT dispersion from the 10 lead electrocardiogram was also examined once the 12 lead minimum and maximum values had been removed. The QT distribution is the curve describing the distance from the mean for all QT intervals (ms). RESULTS: All measures of QT dispersion were increased significantly in left ventricular hypertrophy and tended to increase in those with heart failure. The QT distribution was abnormal in both heart failure and left ventricular hypertrophy. There was no relation between the degree of change in QT dispersion and the incidence of ventricular arrhythmia on 24 hour Holter monitoring. Also there was no relation between QT dispersion and autonomic or mechanical abnormalities. The QT dispersion was related to QRS duration. CONCLUSION: Though QT dispersion and distribution are abnormal in left ventricular hypertrophy these findings do not support the hypothesis that QT dispersion reflects arrhythmic risk in either hypertrophy or heart failure.

Action Potentials↗