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Biomedical subjects

D A Murphy

Publications and source records attributed to D A Murphy.

At least 37 records · Page 2Linked to original sources
PubMed2000

Marijuana use among HIV-positive and high-risk adolescents: a comparison of self-report through audio computer-assisted self-administered interviewing and urinalysis.

The validity of self-report of drug use has been found to vary widely. Moreover, previous research has focused on samples of adults. In 1996-1998, human immunodeficiency virus (HIV)-infected adolescents and high-risk, noninfected adolescents (n = 182) were recruited at 16 locations in 13 US cities into the Reaching for Excellence in Adolescent Care and Health (REACH) project, to the authors' knowledge, the first national study of disease progression among HIV-positive adolescents who were infected through sexual behavior or injection drug use. Self-report of marijuana use was assessed through audio computer-assisted self-administered interviewing (ACASI). Urines were tested for marijuana at a certified laboratory by using the enzyme-multiplied immunoassay technique. Conditional kappas for 2-, 5-, and 7-day self-reports were 0.57, 0.71, and 0.69, respectively. Maximum sensitivity was obtained from a combination of ACASI and urine drug testing. Contrary to previous studies, the data suggest that if a single evaluative instrument is to be used for prevalence, ACASI is more sensitive than urine drug testing for marijuana overall, but particularly for HIV-infected adolescents.

Adolescent↗
PubMed2000

Pathology of intrinsic cardiac neurons from ischemic human hearts.

Various populations of intrinsic cardiac neurons influence regional cardiac function tonically. It is not known whether such neurons are affected by disease states and, if so, in what manner. Therefore, the morphology of intrinsic cardiac ganglia obtained from patients with angiographic evidence of compromised regional coronary blood supply was studied. Posterior atrial ganglia and surrounding fat, removed at the time of cardiac surgery, were placed immediately in saline and within 15-120 min (average of about 40 min) in 0.5% paraformaldehyde/2.5% glutaraldehyde. In 32 studied ganglia, 35% of 473 intrinsic cardiac neurons displayed striking pathological changes at the light and ultrastructural level. The other cells displayed normal morphology. The cytoplasm of 74% of the abnormal cells had one or more of three types of inclusions: (1) darkly stained lamellated inclusions (Type I), (2) membrane-bound whorls and parallel arrays of lightly stained membranes, as well as fine granular material (Type II), or (3) concentric layers of lightly stained membranes with a darker, granular core (Type III). Neurons with inclusions were markedly enlarged (66 x 54 microm vs. 40 x 34 microm for normal neurons) and displayed fewer dendrites. Some neurons contained electron lucent vacuoles indicative of degeneration while others showed frank degeneration, being fragmented, shrunken, and misshapen. Phagocytic cells containing lamellated inclusions and cellular debris were found in ganglia with abnormal neurons. Some axon terminals also displayed degenerative changes. The identification of pathological changes in the human intrinsic cardiac nervous system has implications with respect to the functional integrity of this final common regulator of cardiac function in disease states.

Adult↗
PubMed2000

The heart reinnervates after transplantation.

BACKGROUND: Whether cardiac reinnervation occurs after transplantation remains controversial. If reinnervation does occur, how sympathetic and parasympathetic efferent neurons do this remains unknown. METHODS: Power spectral analysis of heart rate variability was assessed for 1 year after cardiac autotransplantation in 9 dogs. After induction of anesthesia 13 months after transplantation, cardiac and intrinsic cardiac neuronal responses elicited by both electrical stimulation of parasympathetic or sympathetic efferent neurons and systemic or local coronary artery administration of nicotine (5 microg/kg), angiotensin II (0.75 microg/kg), and tyramine (1.2 microg/kg) were studied. The transmembrane electrical properties of intrinsic cardiac neurons were studied in vitro. Ventricular tissue catecholamine content, alpha-tubulin expression, and beta-adrenergic receptor density and affinity were studied. The presence of axons crossing suture lines was sought histologically. RESULTS: Nerves were identified crossing suture lines. Electrical or chemical (ie, nicotine or angiotensin II) activation of sympathetic efferent neurons enhanced cardiodynamics, as did tyramine. Stimulating vagal efferent preganglionic axons induced bradycardia in half of the dogs. Functional reinnervation did not correlate with specific power spectra derived from rate variability in the conscious state. Responding to nicotine and angiotensin II in situ, transplanted intrinsic cardiac neurons generated spontaneous activity. These neurons displayed nicotine-dependent synaptic inputs in vitro. Ventricular tissue had normal beta-adrenergic receptor affinity and density but reduced catecholamine and alpha-tubulin contents. CONCLUSIONS: The intrinsic cardiac nervous system receives reduced input from extracardiac sympathetic efferent neurons after transplantation and inconsistent input from parasympathetic efferent preganglionic neurons. These heterogeneous neuronal inputs are not reflected in heart rate variability or ventricular beta-adrenergic receptor function. Transplanted angiotensin II-sensitive intrinsic cardiac neurons exert greater cardiac control than do nicotine-sensitive ones. The intrinsic cardiac nervous system remodels itself after cardiac transplantation, and this indicates that direct assessment of extracardiac and intrinsic cardiac neuronal behavior is required to fully understand cardiac control after transplantation.

Animals↗
PubMed2000

Psychological distress among HIV(+) adolescents in the REACH study: effects of life stress, social support, and coping. The Adolescent Medicine HIV/AIDS Research Network.

PURPOSE: To investigate the effects of life events, social support, and coping on anxiety and depression among human immunodeficiency virus (HIV)-infected adolescents. It was hypothesized that higher levels of stressful events would be associated with higher levels of anxiety and depression, but that this association would be moderated by satisfaction with social support and by adaptive coping. METHODS: HIV-infected adolescents from 16 locations in 13 U.S. cities (N = 230, median age 16.09 years, standard deviation 1.2, range 13-19; 77% females) were recruited into the Reaching for Excellence in Adolescent Care and Health (REACH) project. REACH is the first large-scale disease progression study of HIV(+) adolescents infected through sexual behavior or injection drug use. The adolescent assessment was conducted by audio-computer assisted self-interview. Least squares regressions were used to test hypotheses. RESULTS: Life events with high impact were associated with higher levels of depression and anxiety. Frequently reported events included: being prescribed medications (74%), family financial problems (61%), and parental alcohol abuse (20%). Contrary to expectations, the buffering hypotheses of social support and adaptive coping were not supported. Satisfaction with social support and adaptive coping methods were both associated directly with lower levels of depression, but no association was detected between these two measures and anxiety. CONCLUSIONS: Although life event distress was directly associated with psychological distress, neither social support nor adaptive coping seemed to moderate this association. However, both satisfaction with support and adaptive coping were associated directly with depression in HIV-infected adolescents.

Adaptation, Psychological↗
PubMed2000

HIV-infected adolescent and adult perceptions of tuberculosis testing, knowledge and medication adherence in the USA.

HIV-infected adolescent and adult perceptions of tuberculosis (TB) infection rates and physician TB behaviour, and patient knowledge of TB transmission and treatment adherence were assessed. HIV-infected youth (N = 199) from adolescent clinical care sites in three cities and HIV-infected adults (N = 133) in New York were interviewed. Adolescent self-report was compared to medical chart review. Adolescents reported they were significantly less likely to be tested, although testing rates were high for both samples. Approximately 9% of both samples reported infection with TB; the majority of whom reported receiving medication (97%), and consistent medication adherence (93%). The overall mean knowledge score was 66%, with significant age differences: adolescents were less knowledgeable than adults, and young males tended to be less knowledgeable than young females. Age, gender and experience with TB (self-perception of TB, testing history and clinic choice) significantly predicted accuracy of knowledge about TB. Results suggest that if HIV-infected individuals--a population at very high risk and often among the least able to afford health care resources--receive the education and support they need from their community health care sources they may substantially reduce their chances of contracting and spreading TB.

AIDS-Related Opportunistic Infections↗
PubMed2000

Barriers to antiretroviral adherence among HIV-infected adults.

Success of highly active antiretroviral therapies (HAART) relies on HIV-infected patients being able to adhere to complicated treatment regimens for extremely long periods of time. Four focus groups with patients taking antiretrovirals (N = 39) were conducted to: (1) determine what strategies facilitate successful adherence; (2) determine what barriers prevent adherence; and (3) investigate the health-care provider and patient relationship and how it may impact adherence. Quantitative and qualitative information was gathered. Participants were prescribed an average of 15 pills per day (M = 14.7, SD = 6.3, range 4 to 36). Findings from the quantitative data revealed that the three strategies used most often to aid adherence were: carrying special containers for medication; having a health-care provider explain or clarify medication requirements; and carrying food and water for adherence to special instructions. The most difficult barriers for patients were sleeping through dose time, problems in following special instructions, and changes in daily routines. From the qualitative data, four main categories of barriers and aids to adherence emerged: patient characteristics, the health-care provider-patient relationship, the health-care system, and issues related to the medication regimen. Barriers related to the health care provider-patient relationship included patient satisfaction with their provider, as well as quality of communication with the provider. In addition, health-care system barriers caused difficulty in maintaining adherence. Implications for patient as well as provider interventions are discussed.

Adult↗
PubMed2000

Assessment of anxiety and depression in young children: support for two separate constructs.

Validated the interrelatedness of depression and anxiety in young children by testing four latent factor models: dual construct, unrelated; dual construct, correlated; single construct; and second-order or higher order analysis to test that depression and anxiety are primary constructs under the higher order factor of general affective distress. Children (N = 86) were ages 6 to 11, with mothers who were HIV-symptomatic or diagnosed with AIDS. Depression and anxiety measures included the Children's Depression Inventory (Kovacs, 1992), selected items from the Dominic-R (Valla, Bergeron, Berube, Gaudet, & St-Georges, 1994), and the Revised Children's Manifest Anxiety Scale (Reynolds & Richmond, 1985). Structural equation modeling was used to test the models. Model 2 (dual construct, correlated) fit the data better than did Models 1 and 3; results for the higher order model were identical to Model 2, suggesting the higher order model is equivalent to the dual-construct model.

Anxiety Disorders↗
PubMed1999

Hepatic vein to the azygous vein anastomosis for pulmonary arteriovenous fistulae.

Pulmonary arteriovenous fistulae after a cavopulmonary anastomosis have been reported to resolve after hepatic venous return is included in the pulmonary circulation. We report a case in which the hepatic veins were redirected to the pulmonary circulation by connecting them directly to the azygous continuation of the inferior vena cava that had previously been connected to the right pulmonary artery. The patient's arterial saturation of 71% increased to 92% after 6 months.

Adolescent↗
PubMed1999

Effects of alcohol intoxication on parenting behavior in interactions with child confederates exhibiting normal or deviant behaviors.

Experimental analogue methods were used to study how acute alcohol intoxication in parents influences their perceptions of and reactions to child behaviors, as well as their strategies for management of those behaviors. All participating parents had a grade school-aged son, but in half the cases this target child had a diagnosed externalizing disorder, whereas for the remaining half neither the target son nor any other offspring of the parents evidenced any psychopathology. Equal numbers of married fathers, married mothers, and single mothers from each of these groups received either alcoholic or nonalcoholic beverages prior to videotaped interactions with male child confederates who, depending on condition, enacted behaviors characteristic of either normal boys or boys with attention deficit hyperactivity/conduct/oppositional defiant disorders (ADHD/CD/ODD). Results indicated that intoxicated parents rated their ADHD/CD/ODD child partners as less deviant than did sober parents. Alcohol intoxication caused all participant groups to exhibit less attention and productive work and more commands, indulgences, and off-task talk in the interactions. Implications for better understanding of the role of psychosocial factors in the correlation between adult drinking problems and childhood behavior disorders are discussed.

Adult↗
PubMed1999

Substance use and its relationship to depression, anxiety, and isolation among youth living with HIV.

Reductions from lifetime to recent levels of substance use, the time since HIV diagnosis, physical health symptoms, CD4 counts, emotional distress, and social supports were examined among 227 (20% female; 22% African American, 27% Anglo, 35% Latino) youth living with HIV (YLH) ages 13 to 24 years. Substance use pervaded the lives of these youth. Male YLH had used more drugs., more often, and for longer periods than women. However, there had been major reductions in use. Being male, having high emotional distress, and having fewer negative social supports were significantly associated with greater reductions in substance use. There was a trend for the length of time that an individual was seropositive being associated with reductions in substance use. The counterintuitive findings suggest that there must be a re-examination of the role of the social support networks of youth living with HIV, as well as the ways in which emotional distress interacts with risk behaviors.

Journal Article↗
PubMed1999

Improving comprehension and recall of information for an HIV vaccine trial among women at risk for HIV: reading level simplification and inclusion of pictures to illustrate key concepts.

A simplified version of the prototype HIV vaccine material was developed through (a) reducing reading grade level, (b) restructuring of the organization and categorization of the material, (c) adding pictures designed to emphasize key concepts, and (d) obtaining feedback on the simplified version through focus groups with the target population. Low-income women at risk for HIV (N = 141) recruited from a primary care clinic were randomly assigned to be presented the standard or the simplified version. There were no significant differences between the groups in terms of education or Vocabulary, Block Design, and Passage Comprehension scores. Women who received the simplified version had significantly higher comprehension scores immediately following presentation of the material than did women who received the standard version and were also significantly more likely to recall study benefits and risks. These findings were maintained at 3-month follow-up. Implications for informed consent are discussed.

AIDS Vaccines↗
PubMed1999

Neuronally induced augmentation of cardiac output.

OBJECTIVE: To determine whether cardiac output can be augmented by preferentially activating cardiac adrenergic efferent neurons. DESIGN: Elicited cardiac output responses were compared when cardiac myocytes were directly stimulated by a beta1-adrenoceptor agonist versus when they were indirectly influenced by beta2- adrenergic-sensitive cardiac efferent neurons. ANIMALS AND METHODS: The beta1-adrenoceptor agonist dobutamine or the selective beta2-adrenoceptor agonist terbutaline was continuously infused individually into the systemic circulation of 15 anesthetized pigs for 20 mins in 5 and 15 microgram/kg/min doses. Heart rate, left atrial chamber pressure, regional left ventricular intramyocardial systolic pressure, left ventricular chamber pressure and aortic pressure were monitored. Cardiac output was determined via the thermodilution technique before and at 10 min intervals during drug infusions. Ventricular tissues were removed thereafter and immediately frozen in liquid nitrogen for subsequent cardiac myocyte cell surface beta-adrenoceptor analysis. MAIN RESULTS: Both doses of terbutaline increased heart rate (approximately +18%) and cardiac output (approximately +20%). Heart rate (+12%) and cardiac output (+16%) increased when the high dose of dobutamine was tested. Left ventricular intramyocardial systolic pressure was increased by dobutamine (+15%) but not by terbutaline. Porcine ventricular cardiac myocytes primarily possess cell surface beta1-, rather than beta2-, adrenoceptors, making it unlikely that cardiac myocytes were directly affected by the doses of terbutaline tested. CONCLUSIONS: Beta2-adrenoceptor agonists enhance cardiac output primarily as a result of neuronally induced increases in heart rate in the porcine model. Adrenergic efferent neuronal enhancement of heart rate may be an effective way to increase cardiac output independently of directly augmented ventricular dynamics. Further study is required to determine whether the diseased myocardium can be supported by such neurocardiological means.

Adrenergic beta-Agonists↗
PubMed1998

Adolescent gender differences in HIV-related sexual risk acts, social-cognitive factors and behavioral skills.

Variations in perceived HIV risk, peer and partner social norms regarding safe sex, self-efficacy, outcome expectancies, and risk-reduction skills (condom use competence and safe sex negotiation) based on gender and sexual risk level were assessed among 132 heterosexual, sexually active, inner city adolescents. Lower sexual risk status was significantly associated with positive partner norms toward safer sex and with favorable partner reaction outcome expectancies. Interaction effects between gender and sexual risk level were found. Outcome expectancies related to approval from others for safer sex were lowest for females in the low-risk group and for males in the high-risk group. Females perceived peers as more positive about safer sex practices, while males perceived sexual partners as more positive. Additionally, females had higher self-efficacy for making condom use enjoyable and planning to avoid risk situations, but were less comfortable than males when demonstrating condom skills. Adolescents' HIV prevention programs must be tailored for gender and risk status.

Adolescent↗
PubMed1998

Bradycardia induced by intravascular versus direct stimulation of the vagus nerve.

BACKGROUND: Electrical stimulation of the parasympathetic nervous system results in slowing of the heart. We sought to determine whether cardiac vagal efferent axons can be stimulated adequately to induce bradycardia without disturbing the integrity of the thorax. METHODS: Cardiodepressor effects elicited by direct stimulation of a vagus nerve in anesthetized dogs and pigs were compared with those generated when the same nerve was stimulated indirectly through bipolar electrodes placed in the adjacent superior vena cava. RESULTS: The heart rate of dogs decreased by about 80% when electrical stimuli were delivered to the right thoracic vagus at the level of the thoracic outlet through bipolar electrodes placed either in the adjacent superior vena cava (intravascular method) or directly on the nerve (direct method). Maximal responses were achieved with 10-V, 5-ms, and 20-Hz stimuli. In anesthetized pigs, similar bradycardia occurred when the right cervical vagus or the right cranial thoracic vagus was stimulated either directly or indirectly through the intravascular method. Atrial dysrhythmias occurred when the stimulating electrodes were placed by either method within 1 cm of the right atrium in both animal models. CONCLUSIONS: Controlled bradycardia can be induced during operation without the risk of generating cardiac dysrhythmias using electrical stimuli (10 V, 5 ms, and 10 to 20 Hz) delivered to the right cervical vagus nerve or the right cranial thoracic vagus nerve through adjacent intravascular electrodes.

Animals↗
PubMed1998

Atrioventricular septal defect with tetralogy of Fallot: results of surgical correction.

BACKGROUND: The outcome of surgical correction of complete atrioventricular septal defect with tetralogy of Fallot has improved in recent years. Controversy exists about the optimal approach to this complex lesion. Our experience over the past 8 years with a single technique is reviewed. The important anatomic features of this lesion are discussed in relation to our method of repair. METHODS: Between 1988 and 1996, 11 consecutive patients underwent correction of complete atrioventricular septal defect with tetralogy of Fallot. Nine patients had undergone prior palliative shunts. The two-patch technique for atrioventricular septal defect was used. The ventricular septal defect was closed through a right ventriculotomy in each case. The commissure between the superior and inferior bridging leaflets of the left portion of the common atrioventricular valve was closed in each patient. Management of the right ventricular outflow tract was individualized. RESULTS: There was one mortality in the early postoperative period. One patient required reoperation for closure of a dehiscent left atrioventricular valve cleft. All survivors are currently in New York Heart Association functional class I or II at follow-up ranging from 2 to 101 months. CONCLUSIONS: Atrioventricular septal defect with tetralogy of Fallot can be corrected with low mortality using the two-patch technique and closure of the ventricular septal defect through a combined approach using a right ventriculotomy and right atriotomy. Routine closure of the commissure of the left portion of the atrioventricular valve results in a low incidence of regurgitation. A good functional result can be achieved in most patients at intermediate-term follow-up.

Cardiac Surgical Procedures↗
PubMed1998

Number of pregnancies, outcome expectancies, and social norms among HIV-infected young women.

In this descriptive study, researchers examined pregnancies, sexually transmitted diseases (STDs), and sexual behaviors among 67 HIV-infected young women, as well as the women's outcome expectancies and peer and partner norms regarding pregnancy. Many of the women (69%) had been pregnant; 42% had been pregnant at least once since learning their HIV status, with 71% choosing to carry to term, resulting in 25% (N = 5) of the babies infected. The women had positive outcome expectancies related to pregnancy, which were significantly correlated with peer and partner social norms. Lack of knowledge regarding infant transmission, high rates of STDs, and inconsistent condom use all indicate a need for improved intervention regarding pregnancy and decision-making. Suggestions for better methods of providing information to HIV+ young women are provided.

Adolescent↗
PubMed1998

A brief HIV intervention for adolescents and young adults.

The delivery format of an HIV prevention program that had been efficacious with youths at high risk was modified from seven relatively short sessions over a one- to two-month period to three longer sessions over a one- to two-week period. In contrast to youths in the seven-session program, no change in sexual behavior was observed among those in the redesigned program at three-month follow-up. However, change was apparent in the mediators of high-risk behavior over the same period.

Adolescent↗