Search PubMed⌕ Search

Biomedical subjects

D A Murphy

Publications and source records attributed to D A Murphy.

At least 55 records · Page 3Linked to original sources
PubMed1998

Differences between completers and early dropouts from 2 HIV intervention trials: a health belief approach to understanding prevention program attrition.

OBJECTIVES: The purpose of this study was to identify factors predicting program attrition among participants in human immunodeficiency virus (HIV) risk reduction trials. METHODS: Participants were gay/bisexual men and severely mentally ill adults recruited to take part in HIV risk reduction small-group interventions. Program completers were compared with participants who were assessed at baseline but then failed to attend any sessions. The health belief model provided a framework for selection of possible predictors of program attrition. RESULTS: Younger age was associated with early dropout in both samples. Other predictors among gay/bisexual men included involvement in an exclusive sexual relationship, minority ethnicity, injection drug use, and higher perceived severity of AIDS. Severely mentally ill dropouts were less knowledgeable about safer sex methods and more likely to hold positive outcome expectancies for condom use. CONCLUSIONS: Evaluation of intervention effectiveness among vulnerable population segments is threatened if there is selective attrition. Better methods are needed to attract and maintain participation in HIV prevention programs. Alternatively, wider application of "intention to treat" analysis of intervention outcomes is recommended to minimize selection bias due to program dropout.

Adult↗
PubMed1998

Effects of deviant child behavior on parental alcohol consumption. Stress-induced drinking in parents of ADHD children.

Distress and ad lib alcohol consumption after interactions with child confederates were investigated in parents of children with externalizing disorders--attention-deficit hyperactivity disorder (ADHD), conduct disorder (CD), or oppositional defiant disorder (ODD). Sixty subjects interacted with boys trained to act like either normal children or children with ADHD/CD/ODD. Interactions with deviant confederates resulted in feelings of inadequacy and produced negative affect but had no effect on alcohol consumption. Post hoc analyses showed that parents with a family history of alcohol problems (FH+) showed increased drinking after interaction with a deviant confederate, compared with FH+ parents who interacted with the normal confederate. FH- parents showed the opposite pattern of results.

Adult↗
PubMed1997

Randomised, controlled, community-level HIV-prevention intervention for sexual-risk behaviour among homosexual men in US cities. Community HIV Prevention Research Collaborative.

BACKGROUND: Community-level interventions may be helpful in population-focused HIV prevention. If members of populations at risk of HIV infection who are popular with other members can be engaged to advocate the benefits of behaviour change to peers, decreases in risk behaviour may be possible. We assessed a community-level intervention to lower the risk of HIV infection, focusing on men patronising gay bars in eight small US cities. METHODS: We used a randomised community-level field design. Four cities received the intervention and four control cities did not. Participants were men from each city who went to gay bars. Men completed surveys about their sexual behaviour on entering the bars during 3-night periods at baseline and at 1-year follow-up. In the control cities, HIV educational materials were placed in the bars. In the intervention cities, we recruited popular homosexual men in the community and trained them to spread behaviour-change endorsements and recommendations to their peers through conversation. FINDINGS: Population-level of risk behaviour decreased significantly in the intervention cities compared with the control cities at 1-year follow-up, after exclusion of surveys completed by transients and men with exclusive sexual partners in a city-level analysis, in the intervention cities we found a reduction in the mean frequency of unprotected anal intercourse during the previous 2 months (baseline 1.68 occasions; follow-up 0.59: p = 0.04) and an increase in the mean percentage of occasions of anal intercourse protected by condoms (baseline 44.7%; follow-up 66.8%, p = 0.02). Increased numbers of condoms taken from dispensers in intervention-city bars corroborated risk-behaviour self-reports. INTERPRETATION: Popular and well-liked members of a community who systematically endorse and recommend risk-reduction behaviour can influence the sexual-risk practices of others in their social networks. Natural styles of communication, such as conversations, brought about population-level changes in risk behaviour.

Adult↗
PubMed1997

The impact of illness disclosure and custody plans on adolescents whose parents live with AIDS.

OBJECTIVES: To describe the disclosure and custody planning of parents living with AIDS and the impact of these on their adolescents' adjustment. METHODS: An examination of the association of multiple behaviour problems in children and the illness disclosure and custody plans of their parents living with AIDS. RESULTS: Both mothers (87%) and fathers were significantly more likely to disclose their HIV serostatus to adolescents (73%), compared with younger children (23%); only 44% disclosed their illness to all their children; 11% disclosed to none. Most parents (80%) living with AIDS had discussed their custody plans. However, only 30% initiated legal plans, typically for younger children. Adolescents who were informed of their parents' serostatus engaged in more sexual risk acts, smoked more cigarettes, and reported more severe substance use and greater emotional distress than uninformed adolescents. Legal custody arrangements were not associated with adolescent adjustment at recruitment or follow-up. CONCLUSIONS: A longitudinal analysis of the impact on adolescents of the behaviours of parents living with AIDS is needed.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Gross and microscopic anatomy of the human intrinsic cardiac nervous system.

BACKGROUND: The extent and locations of intrinsic cardiac ganglia on the human heart were investigated to facilitate studying their function. METHODS: The locations and number of major intrinsic cardiac ganglia were determined in six human hearts by means of microdissection following methylene blue staining. Light and electron microscopic analyses were performed on right atrial and cranial medial ventricular ganglia obtained from 12 other human hearts. RESULTS: Gross anatomy: Collections of ganglia associated with nerves, i.e., ganglionated plexuses, were observed consistently in five atrial and five ventricular regions. Occasional ganglia were located in other atrial and ventricular regions. Atrial ganglionated plexuses were identified on 1) the superior surface of the right atrium, 2) the superior surface of the left atrium, 3) the posterior surface of the right atrium, 4) the posterior medial surface of the left atrium (the latter two fuse medially where they extend anteriorly into the interatrial septum), and 5) the inferior and lateral aspect of the posterior left atrium. Ventricular ganglionated plexuses were located in fat 1) surrounding the aortic root, 2) at the origins of the right and left coronary arteries (the latter extending to the origins of the left anterior descending and circumflex coronary arteries), 3) at the origin of the posterior descending coronary artery, 4) adjacent to the origin of the right acute marginal coronary artery, and 5) at the origin of the left obtuse marginal coronary artery. Microscopic anatomy: Ganglia ranged in size from those containing a few neurons to large ganglia measuring up to 0.5 x 1 mm. The human heart is estimated to contain more than 14,000 neurons. Neuronal somata varied in size and shape. Many axon terminals in intrinsic cardiac ganglia contained large numbers of small, clear, round vesicles that formed asymmetrical axodendritic synapses, whereas a few axons contained large, dense-cored vesicles. CONCLUSIONS: The human intrinsic cardiac nervous system is distributed more extensively than was considered previously, most of its ganglia being located on the posterior surfaces of the atria and superior aspect of the ventricles. Each ganglion therein contains a variety of neurons that are associated with complex synaptology.

Adult↗
PubMed1997

Effects of deviant child behavior on parental distress and alcohol consumption in laboratory interactions.

Levels of adult distress and ad lib alcohol consumption following interactions with child confederates were investigated in parents of children with no diagnosable psychiatric disorders. Sixty parents (20 married couples and 20 single mothers) interacted with boys trained to enact behaviors characteristic of either normal children or "deviant" children with externalizing behavior disorders--attention-deficit hyperactivity disorder (ADHD), conduct disorder (CD), and oppositional defiant disorder (ODD). Relative to the normal child role, interactions with deviant confederates were rated as significantly more unpleasant, resulted in feelings of role inadequacy, and produced significantly more anxiety, depression, and hostility. After the interactions, parents were given the opportunity to drink as much of their preferred alcoholic beverage as they desired while anticipating a second interaction with the same child. The participants consumed more alcohol following exposure to deviant as opposed to normal confederates.

Adult↗
PubMed1997

Reduction in risk behavior among adults with severe mental illness who learned to advocate for HIV prevention.

OBJECTIVES: The study evaluated the relative impact of HIV risk reduction interventions for adults with severe mental illness living in the inner city. METHODS: A total of 104 chronically mentally ill men and women were interviewed to determine sexual risk behavior over the past month and to assess HIV risk-related psychological characteristics, including their knowledge about risk behavior, their belief in their ability to change their behavior, their perceptions of peer and social norms about safer sex, their expectancies about the outcomes of these changes, and their perceived barriers to condom use. Participants were then randomly assigned to one of three conditions: a single AIDS education session, a seven-session cognitive-behavioral HIV risk reduction group intervention, or a seven-session group intervention that combined the cognitive-behavioral intervention with training to act as a risk reduction advocate to friends (advocacy training). Individuals were reinterviewed three months after completion of the intervention. RESULTS: Although all participants exhibited change at follow-up in some risk-related psychological characteristics and sexual risk behaviors, participants who received the cognitive-behavioral intervention that included the advocacy training reported greater reductions in rates of unprotected sex and had fewer sexual partners at follow-up. CONCLUSIONS: HIV prevention interventions that teach risk reduction skills and then encourage participants to advocate behavior change to others appear to strengthen participants' capacity to change their behavior to reduce HIV risk, even those from a disenfranchised group such as severely mentally ill adults.

Adult↗
PubMed1996

Cardiac augmentation can be maintained by continuous exposure of intrinsic cardiac neurons to a beta-adrenergic agonist or angiotensin II.

The purpose of this work was to determine whether constant increases in cardiac rate and force can be induced by continuous exposure (20 min) of intrinsic cardiac neurons to pharmacological agents which activate such neurons. Intrinsic cardiac neurons within the ventral right atrial ganglionated plexus were activated by constant infusions of dobutamine or angiotensin II (100 microM/min for 10 min followed by 200 microM/min for 10 min) via their local arterial blood supply in 12 artificially ventilated, open chest anesthetized dogs while monitoring heart rate and indices of regional cardiac contractility. The results were as follows: (1) Dobutamine (100 microM/min for 10 min) enhanced intrinsic cardiac neuronal activity by 195% at first, neuronal activity declining thereafter to +79% of control values in the continued presence of this agonist. When the dose of dobutamine was doubled (200 microM/min for 10 min) neuronal activity increased +179% above control values and remained elevated, as did heart rate as well as right and left ventricular contractility. (2) Angiotensin II (100 microM/min) increased neuronal activity at first, with neuronal activity decreasing gradually thereafter such that after 5 min of exposure activity reached control values. Neuronal activity did not increase further when neurons were subsequently exposed to a higher dose of angiotensin II (200 microM/min). Heart rate and ventricular contractility were increased initially more by angiotensin II than by dobutamine. However, cardiac indices fell thereafter concomitant with reductions in neuronal activity as the exposure to angiotensin II continued. Thus although cardiac rate and force initially were increased more by angiotensin II than by dobutamine, similar augmentation of cardiac indices was achieved by sustained exposure of a population of intrinsic cardiac neurons to either agent. In conclusion, heart rate and ventricular contractility can be enhanced for relatively prolonged periods of time by continuous exposure of a population of intrinsic cardiac neurons to a beta-adrenoceptor agonist or angiotensin II, with the beta-adrenoceptor agonist inducing more consistent cardiac augmentation than angiotensin II.

Angiotensin II↗
PubMed1996

Factors in the early failure of cryopreserved homograft pulmonary valves in children: preserved immunogenicity?

METHODS: Between 1990 and 1995, 48 homograft valves (15 aortic and 33 pulmonary), cryopreserved on-site, were implanted to reconstruct the right ventricular outflow tracts in 44 children (mean age 6.2 +/- 6.0 years; range 3 days to 20.2 years). Blinded serial echocardiographic follow-up evaluation was performed for all 45 valves in the 41 survivors. RESULTS: Four homograft valves were replaced because of pulmonary insufficiency (3) or stenosis and insufficiency (1). Freedom from reoperation was 90% (70% interval, 84% to 97%) at 50 months. During the follow-up period 15 valves developed progressive pulmonary insufficiency of at least two grades. Three valves developed transvalvular gradients of > or = 50 mm Hg, and one of these valves was also insufficient. The freedom from echocardiographic failure (two or more grades of pulmonary regurgitation or > or = 50 mm Hg gradient) was 44% at 50 months (70% confidence interval, 32% to 55%). Young age (p = 0.03), low operative weight (p = 0.04), small graft size (p = 0.04), and homograft retrieval-to-cryopreservation time of less than 24 hours (p = 0.02) were significantly associated with failure. The type of donor valve (pulmonic or aortic), donor age, and blood group mismatch were not associated with failure, although blood group mismatch approached significance (p = 0.05). CONCLUSIONS: Homografts function well as conduits between the pulmonary ventricle and pulmonary arteries if long-term valve competency is not crucial. However, many rapidly become insufficient. This has important implications for the choice of a valve if the indication for valve replacement is to protect a ventricle failing due to pulmonary insufficiency. Short periods between homograft retrieval and cryopreservation enhance viability and antigenicity. This may suggest an immunologic basis for the failure.

Adolescent↗
PubMed1995

Predictors of high and low levels of HIV risk behavior among adults with chronic mental illness.

OBJECTIVE: Several recent studies confirm elevated rates of human immunodeficiency virus infection among acute and chronic mentally ill adults in large urban areas. This research sought to characterize risk for HIV infection among adults with chronic mental illness and to examine psychosocial factors predictive of risk. METHODS: Two hundred and twenty-five adults with chronic mental illness who were sexually active in the past year outside of exclusive relationships were individually interviewed in community mental health clinics using a structured HIV risk assessment protocol. RESULTS: More than 50 percent of the study participants were sexually active in the past month, and 25 percent had multiple sexual partners during that period. Fifteen percent of the men had male sexual partners. In more than 75 percent of occasions of sexual intercourse, condoms were not used. When participants were categorized as at either high or lower risk for HIV infection based on their pattern of condom use, psychosocial factors that predicted risk level included measures of participants' self-reported efficacy in using condoms, perceptions of social norms related to safer sex among peers and sexual partners, and expectations about outcomes associated with condom use, as well as participants' level of objectively assessed behavioral skills in negotiation and assertiveness in sexual situations. CONCLUSIONS: Interventions aimed at prevention of HIV and AIDS are urgently needed in settings that provide services to persons with chronic mental illness.

Adolescent↗
PubMed1995

Cost-effectiveness and efficacy of an on-site homograft heart-valve bank.

OBJECTIVE: To compare the performance and cost-effectiveness of cryopreserved homograft cardiac valves prepared on site to valves prepared commercially. DESIGN: A review of all patients who received homograft heart valves between January 1990 and December 1993, with cost-effectiveness analysis. Follow-up ranged from 1 to 37 months (mean 12 months). SETTING: Tertiary-care adult and pediatric hospitals. PATIENTS: All consecutive patients receiving homograft heart valves in either the aortic or right ventricular outflow tract (RVOT) position since on-site preparation of cryopreserved cardiac valves began in 1990. Forty-three patients received 47 homograft valve replacements: 18 in the aortic position and 29 in the RVOT position. No patients were lost to follow-up. MAIN OUTCOME MEASURES: Valve function as assessed by patient survival, actuarial freedom from reoperation and Doppler echocardiographic assessment of transvalvar gradients and valvar insufficiency. Cost-effectiveness as assessed by a formal evaluation of on-site costs compared with current prices for commercially prepared valves. RESULTS: There were four operative deaths but no late deaths. Four valves were removed. Freedom from reoperation at 3 years was 100% for aortic valve replacement and 85% for RVOT reconstruction. Echocardiographic follow-up of 34 of the remaining 39 patients showed mild or no insufficiency in 24 valves, moderate insufficiency in 8 valves and severe, but not clinically significant, insufficiency in 2 valves. The cost of on-site preparation of the valves was $1363 compared with $5040 for the commercially prepared valves, a cost saving for the group of $172,819. CONCLUSION: On-site preparation is an effective method of preparing cryopreserved cardiac valves and permits significant cost savings.

Cost-Benefit Analysis↗
PubMed1995

Evidence of type 2 herpes simplex infection in human coronary arteries at the time of coronary artery bypass surgery.

OBJECTIVE: To examine histologically biopsies from the coronary arteries of patients undergoing coronary artery bypass grafting (CABG) for evidence of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) antigen and to correlate the incidence with pathological and clinical data. DESIGN: Sequential patients undergoing CABG in whom adequate tissue could be obtained for histology. SETTING: University teaching hospital. PATIENTS: Forty-six patients were enrolled. Thirty-one provided sufficient tissue and clinical information for the analysis. METHODS: Biopsy material was collected in the operating room and prepared immediately for histology and electron microscopy. Slides were prepared by staining with hematoxylin and eosin, Masson trichrome, avidin biotin complex immunoperoxidase for HSV-1 and HSV-2 protein and specific DNA probes for HSV-1 and HSV-2 by hybridization. Clinical data were obtained in structured interviews. RESULTS: Sixty-one per cent of biopsies demonstrated evidence of inflammation, 45% were positive for antigen to HSV-2 and only one to HSV-1. Significant positive correlations were detected between inflammatory cells in the biopsy and a recent history of cold sores and between the presence of the infiltrate and positivity to HSV-2 antigen. CONCLUSION: A correlation exists between HSV-2 infection and the inflammatory response associated with atherosclerosis.

Adult↗
PubMed1995

Effects of acutely raising intracranial pressure on cardiac sympathetic efferent neuron function.

OBJECTIVE: To determine whether acutely raising intracranial pressure modifies the function of cardiac efferent autonomic neurons. METHODS: The effects of suddenly raising intracranial pressure above systemic vascular pressure on heart rate, left atrial and left ventricular chamber pressures, as well as right and left ventricular intramyocardial pressures, were studied following removal of the adrenal glands from the circulation. Cardiac effects induced by systemic administration of nicotine, tyramine or isoproterenol were investigated before and after raising intracranial pressure: (1) in 9 dogs with neurally intact hearts in which cardiac release of catecholamines and intrinsic cardiac neuronal activity were studied; (2) in another 8 dogs in which intrathoracic autonomic neurons were disconnected from central neurons; (3) in another 8 dogs after decentralizing intrathoracic sympathetic but not parasympathetic neurons; (4) in 2 animals after decentralizing intrathoracic parasympathetic, not sympathetic neurons. RESULTS: Increasing intracranial pressure in neurally intact preparations induced ventricular augmentation followed by depression such that after 12 min of cerebral ischemia left ventricular systolic pressure was 62 +/- 5 mmHg. Isoproterenol and tyramine augmented right ventricular inotropism similarly before and after raising intracranial pressure, their effects on left ventricular systolic pressures being reduced secondary to the systemic vascular hypotension. Although nicotine excited intrinsic cardiac neurons similarly before and after raising intracranial pressure, it failed to enhance cardiac liberation of noradrenaline after compared to before raising intracranial pressure. Nicotine-induced ventricular augmentation was obtunded after brain death despite the fact that ventricular myocytes underwent no detectable histological changes. In contrast, nicotine induced similar cardiac augmentation before and after raising intracranial pressure when intrathoracic autonomic neurons or when intrathoracic sympathetic, not parasympathetic neurons, were decentralized. CONCLUSION: Cardiac sympathetic efferent neuronal function is obtained by acutely raising intracranial pressure.

Adrenalectomy↗
PubMed1994

Interaction of Mycoplasma hyopneumoniae and Pasteurella multocida infections in swine.

To investigate the interaction between Mycoplasma hyopneumoniae and Pasteurella multocida infection, 32 pigs were randomly assigned by litter, sex, and weight to 4 treatment groups. Group-1 pigs were inoculated with M hyopneumoniae and allowed to recover from M hyopneumoniae infection. Group-2 pigs were vaccinated against M hyopneumoniae and then inoculated with M hyopneumoniae. Group-3 pigs were inoculated with M hyopneumoniae and developed clinical signs of mycoplasmosis. Group-4 pigs had never been exposed to M hyopneumoniae. All pigs were initially seronegative for M hyopneumoniae. All pigs were subsequently inoculated with P multocida and euthanatized 2 weeks later. Pasteurella multocida was isolated only from the lungs of group-3 pigs, and these pigs had a significantly higher median percentage of lung surface area affected by pneumonia than did pigs in the other groups. For group-3 pigs, percentage of lung surface area affected by pneumonia was positively correlated with the number of P multocida colonies isolated. We concluded that P multocida is not a primary respiratory pathogen in pigs, but that M hyopneumoniae infection can render the lungs susceptible to P multocida colonization and infection. Pigs recovered from or vaccinated against infection with M hyopneumoniae were resistant to P multocida infection.

Animals↗
PubMed1994

The algebra of managed care. Creating physician and hospital partnerships.

As healthcare faces an economic reengineering, hospitals and physicians are faced with new challenges. It is the first time that they have had joint economic interests, and survival for both is dependent on designing new economic models. This article describes the economic interrelationship between hospitals and physicians and provides insight into opportunities to encourage new levels of collaboration between them.

Contract Services↗