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Biomedical subjects

D Luke

Publications and source records attributed to D Luke.

At least 19 recordsLinked to original sources
PubMed2006

Successful perioperative utilisation of inhaled nitric oxide in mitral valve surgery.

Pulmonary hypertension associated with mitral valve disease can significantly complicate mitral valve replacement. Nitric oxide (NO) has an established role in congenital heart surgery and in cardiac transplantation. However the evidence to date suggests that iNO does not provide a clinical advantage in pulmonary hypertension associated with valvular heart disease. We discuss a 56-year-old male with acute mitral incompetence who underwent emergency surgery. Following mitral valve replacement he was weaned off cardiopulmonary bypass with an intra-aortic balloon pump and high doses of inotropic support but continued to be hypotensive. Inspection of the heart showed right-sided dysfunction and evidence of pulmonary hypertension. Following the introduction of iNO he rapidly improved. He was successfully separated from the cardiopulmonary bypass support and subsequently made a full recovery and was discharged. We believe that this case demonstrates the utility of iNO in the management of pulmonary hypertension secondary to valvular disease in the acute setting. This is in contrast to the evidence against its utility in established pulmonary hypertension in chronic valvular heart disease. Further confirmation of this observation may lead to the therapeutic use of NO in this subpopulation of cardiac surgery patients.

Administration, Inhalation↗
PubMed2005

Strength of clean indoor air laws and smoking related outcomes in the USA.

OBJECTIVES: Environmental tobacco smoke (ETS) is often encountered in the workplace. There have been efforts to apply and enforce state laws limiting workplace smoking. There has been little study of the relative effectiveness of state and/or local laws in affecting both rates of workplace ETS exposure and adult smoking rates. This study investigates these hypotheses, as well as the effect of these laws on youth smoking. DESIGN: This is a secondary data analysis using sources including the Current Population Survey (CPS), Behavioral Risk Factor Surveillance System (BRFSS), Youth Risk Behavior Survey (YRBS), and the National Household Survey of Drug Abuse (NHSDA) between the years of 1996 and 1999. Linear regression models were used to investigate the effect of a state's clean indoor air (CIA) law (using a measure of extensiveness) on the overall amount of people who reported working in a smoke-free environment, youth smoking rates and adult smoking rates. RESULTS: The extensiveness of a state's CIA law was found to be a reliable predictor of the percentage of indoor workers who report a smoke-free work environment and the rates of youth smoking. State CIA laws were not conclusively associated with adult smoking rates. CONCLUSIONS: The extensiveness of a state's CIA law is strongly associated with a higher percentage of indoor workers reporting a smoke-free work environment. This study did not reveal a similar association between local laws and smoke-free work environments. Youth smoking rates, shown to be related to state CIA laws, may be further affected with more stringent CIA policy.

Adolescent↗
PubMed2001

Teens' images of smoking and smokers.

The authors used qualitative and quantitative data to identify and interpret specific images teens have about smoking and smokers. Qualitative data were collected in 1996 from 793 teenagers participating in 125 focus groups at eight different sites across the United States. Most focus groups were homogeneous with respect to gender, ethnicity, and smoking status. Ages ranged from 12 to 18 years, and about half of the participants were female. The majority of participants (62%) were white and African American, the remainder (38%) were Hispanic, American Indian, and Asian/Pacific Islander. Groups were comprised of smoking and nonsmoking teens. Focus group activities were used to elicit image-related discussions about attitudes, beliefs, and perceptions of smoking. Investigators identified seven consistent and distinctive image themes: Appearance (smoking is dirty and unattractive), Activity (nonsmokers have busy, active lives), Drugs and sex (smokers are substance abusers and are sexually active), Rebellion (smokers belong to rebellious groups), Affect (smokers are depressed, angry, and stressed-out), In control (nonsmokers have self-control and are independent), and Pride (nonsmokers are proud of themselves, their families, and their heritage). A large scale, multi-site qualitative research approach can increase understanding of teen smoking. The identification of distinctive images of smoking can help researchers develop more sophisticated models of the processes of teen smoking than currently exist.

Adolescent↗
PubMed2001

Lack of an effect of azithromycin on the disposition of zidovudine and dideoxyinosine in HIV-infected patients.

Two studies were conducted in HIV-infected subjects to assess the potential for azithromycin to interact with zidovudine and dideoxyinosine. Both studies used 12 subjects. The zidovudine study dosed subjects with 1200 mg/day of azithromycin (n = 7) (later changed to 600 mg/day [n = 5]) for Days 8 to 21 of a 21-day course of 100 mg, five times/day of zidovudine. Subjects treated with 200 mg of dideoxyinosine twice daily for 21 days received 1200 mg of azithromycin or an equivalent amount of placebo/day for Days 8 to 21. Antiretroviral plasma and urine sampling were conducted on Days 1, 7, and 21 for zidovudine and on Days 7 and 21 for dideoxyinosine. Peripheral mononuclear cells were also collected for quantitation of phosphorylated zidovudine. Azithromycin had no significant impact on the Cmax and AUC of zidovudine, although it significantly decreased the zidovudine tmax by 44% and increased the intracellular exposure to phosphorylated zidovudine by 110%. Azithromycin had no significant effect on dideoxyinosine pharmacokinetics. Based on the results of these studies, it is concluded that azithromycin may be safely coadministered with both zidovudine and dideoxyinosine.

Adolescent↗
PubMed2000

Smoke signs: patterns of tobacco billboard advertising in a metropolitan region.

OBJECTIVE: To use geographic information systems data and analyses to describe locations and characteristics of tobacco billboards in a large metropolitan area, and to assess the extent to which tobacco companies are locating billboards in close proximity to minority neighbourhoods and schools. DESIGN: Observational study of billboards in a large metropolitan region. SETTING: City and county of St Louis, Missouri. PARTICIPANTS: All stationary billboards in the city and county of St Louis were eligible to be observed, with the exception of bus stop and street side retail advertising signs (for example, cigarette advertising at gas stations). A total of 1239 non-blank billboards were observed. All data were collected in early 1998. MAIN OUTCOME MEASURES: Tobacco and non-tobacco billboard geographic distribution; billboard type and product brand frequencies; and billboard neighbourhood characteristics. RESULTS: Almost 20% of the billboards contained tobacco advertising. Four of the top five and nine of the top 22 brands displayed on billboards were tobacco products. Billboards were located in all areas of St Louis except for the communities with the highest average incomes. Tobacco billboards were more likely to be found in low income areas and areas with a higher percentage of African Americans. Images of African American figures on tobacco billboards were concentrated in the most heavily African American populated regions of the city. Approximately 74% of all billboards in the city of St Louis were within 2000 feet (700 metres) of public school property. CONCLUSIONS: Tobacco products were the single most heavily advertised type of product on billboards in St Louis. The geographic distribution of tobacco billboards, as well as the types of images found on these billboards, is consistent with the hypothesis that tobacco companies are targeting poor and minority communities with their advertising. Methods employing geographic information systems are a powerful technique for examining outdoor tobacco advertising.

Advertising↗
PubMed1999

HIV risk behaviours among male-to-female transgenders in comparison with homosexual or bisexual males and heterosexual females.

Issues and concerns among six directors, one counsellor and one consultant for transgender programmes in San Francisco are described. Additionally, 173 clients who were enrolled in programmes in eight AIDS service organizations were interviewed using a structured survey questionnaire. This study examined the relationships between HIV risk behaviours and social and cognitive factors among transgendered females (male-to-female transgenders) (n = 25) in comparison with homosexual or bisexual males (n = 122) and heterosexual females (n = 26). Transgendered females engaged in riskier behaviours than the other groups in terms of the number of sex partners in the past 30 days and the past six months, commercial sex activities, and having a steady sex partner who injected drugs. Adverse socioeconomic conditions and transgender-specific risk behaviours such as injecting hormones in relation to HIV risk behaviours must be targeted by future intervention studies.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Analysis of postdischarge change in a dual diagnosis population.

Many individuals with serious mental illnesses have co-occurring drug and alcohol problems. The research reported in this article examined an integrated inpatient mental illness-chemical dependency program and compared it with standard inpatient psychiatric treatment for two groups: those demonstrating high change from baseline to two-months postdischarge and those with negative or no change. Univariate analyses revealed significant differences in the change groups on baseline personal-clinical characteristics and on aspects of their social and physical environments. The results have implications for improving mental health practice by better predicting patients who will optimally benefit from inpatient treatment.

Adult↗
PubMed1998

Oral trovafloxacin compared with intravenous cefoxitin in the prevention of bacterial infection after elective vaginal or abdominal hysterectomy for nonmalignant disease. Trovafloxacin Surgical Group.

BACKGROUND: Trovafloxacin is a new fourth-generation fluoroquinolone whose pharmacokinetics and in vitro activity suggest that it is well suited for antibiotic prophylaxis in elective hysterectomy. METHODS: In a randomized, double-blind, multicenter study, parallel groups of women 18 years of age or older received either 200 mg trovafloxacin by mouth and intravenous (i.v.) placebo or 2 g cefoxitin by i.v. infusion and placebo by mouth before elective vaginal or abdominal hysterectomy for nonmalignant disease. RESULTS: In the 103 and 97 patients in the trovafloxacin and cefoxitin groups, respectively, who were evaluable for efficacy, the prophylactic success rates at hospital discharge (96% in both groups) and 30 +/- 6 days after hysterectomy (88% and 91% in the trovafloxacin and cefoxitin groups, respectively) were statistically equivalent. Both antibiotics were well tolerated. CONCLUSION: A single oral 200 mg dose of trovafloxacin is as effective and safe as a standard cefoxitin parenteral regimen in the prevention of primary bacterial infection after elective vaginal or abdominal hysterectomy for nonmalignant disease.

Administration, Oral↗
PubMed1998

Long-term clinical outcome following coronary artery bypass grafting for isolated stenosis of the left anterior descending coronary artery.

AIMS: To detail the clinical and angiographic profile, and long-term outcome in consecutive patients with isolated stenosis of the left anterior descending coronary artery undergoing bypass surgery. METHODS: A retrospective study of all patients (n = 301) (January 1984-December 1990) and undergoing coronary artery bypass grafting for isolated left anterior descending disease, in the Irish Republic, was performed. Survival was compared with that of an exact age- and gender-matched cohort. RESULTS: Mean age was 53 (+/- 9.3) years. There were 238 (79%) males. In 241 (80%) patients an internal thoracic arterial bypass graft was used. Operative mortality was 1.3%. Of the 280 (93%) patients alive (16 cardiac deaths) at 7.1 (+/- 1.9) years, 105 (35%) had angina, 26 (9%) suffered an interval myocardial infarction, and repeat revascularization was required on 29 (10%). Female gender (P = 0.002), pre-operative myocardial infarction (P = 0.02), significant diagonal disease (P = 0.04) and postoperative myocardial infarction (P = 0.0001) were independently associated with survival. Females were more likely to develop congestive cardiac failure (P = 0.01) or postoperative angina (P = 0.03) than their male counterparts. CONCLUSIONS: Survivorship (97%) and event-free survival (96%) at 5 years following coronary artery bypass grafting for isolated left anterior descending coronary artery disease is excellent and equivalent to an age-matched and gender-matched cohort.

Adult↗
PubMed1997

Sleep and circadian influences on cardiac autonomic nervous system activity.

To assess the separate contributions of the sleep and circadian systems to changes in cardiac autonomic nervous system (ANS) activity, 12 supine subjects participated in two 26-h constant routines, which were counterbalanced and separated by 1 wk. One routine did not permit sleep, whereas the second allowed the subjects to sleep during their normal sleep phase. Parasympathetic nervous system activity was assessed with respiratory sinus arrhythmia as measured from the spectral analysis of cardiac beat-to-beat intervals. Sympathetic nervous system activity was primarily assessed with the preejection period as estimated from impedance cardiography, although the 0.1-Hz peak from the spectral analysis of cardiac beat-to-beat intervals, the amplitude of the T wave in the electrocardiogram, and heart rate were also measured. Respiratory sinus arrhythymia showed a 24-h rhythm independent of sleep, whereas preejection period only showed a 24-h rhythm if sleep occurred. Thus the findings indicate that parasympathetic nervous system activity is mostly influenced by the circadian system, whereas sympathetic nervous system activity is mostly influenced by the sleep system.

Adult↗
PubMed1996

Inhibition of melatonin secretion onset by low levels of illumination.

Melatonin is a hormone released during darkness under the control of the hypothalamic circadian pacemaker. It has been shown that melatonin is suppressed by light as a function of intensity, with low levels of illumination producing small effects and more intense light greater, but not complete inhibition. The studies which lead to these conclusions administered light subsequent to the secretion pattern being well established. Light as low as 250 lux administered during the normal onset of secretion can reduce melatonin to below detectable levels. The onset of melatonin secretion was delayed for at least an hour during 250 lux exposure and did not rise until termination of light exposure (two hours after control melatonin onset) with higher illumination (500, 1000 and 2500 lux). This tentatively indicates that duration of the inhibition is intensity dependent. It is suggested that the experimental paradigm used in the present study may be a more realistic representation of the effect of normal light exposure (both natural and artificial) on the circadian system, and that findings may be pertinent to the aetiology of certain sleep onset insomnias, which would include delayed sleep phase syndrome (DSPS) and adaptation to shift work.

Adolescent↗
PubMed1995

The haemodynamic effect of prophylactic peri-operative dopexamine in coronary artery bypass patients.

Twenty-three low risk coronary artery bypass graft patients underwent a controlled study of the effects of prophylactic perioperative dopexamine hydrochloride on haemodynamic indices and peripheral perfusion. The infusion commenced following induction of anaesthesia and continued for 24 h postoperatively. The study demonstrated that dopexamine significantly increased cardiac index compared with the control group (P < 0.05) and that this effect was mediated through an increase in both left ventricular stroke volume index and heart rate (P < 0.05). This was associated with a significantly lower systemic vascular resistance (P < 0.05), without an increase in left ventricular stroke work index in the dopexamine group. Despite normal pre-operative left ventricular function, both groups exhibited a fall in pH (P < 0.05) relative to baseline levels. This fall in pH began prior to cardiopulmonary bypass and persisted in the early postoperative period in both groups, suggestive of tissue hypoperfusion and oxygen deficiency. These indices normalized more rapidly in the dopexamine group, suggesting a more rapid reversal of an intra-operative oxygen debt in this group. The study demonstrates the mechanism of action of dopexamine on cardiac function and peripheral perfusion during cardiac surgery and shows that the inodilator properties during cardiac surgery are useful haemodynamically and facilitate early reversal of tissue hypoperfusion and oxygen debt in this environment.

Adult↗
PubMed1993

Atrial myxoma: national incidence, diagnosis and surgical management.

Despite being the most common benign intracardiac tumour with an excellent prognosis after surgical excision the incidence of atrial myxoma (except at autopsy) is unknown. We reviewed all patients admitted to the National Cardiac Surgery Unit (n = 26) with an atrial myxoma over a fifteen year period (1977-1991) to compile national incidence data and assess pre-operative diagnosis, management, surgical technique, and outcome. Preoperative symptoms were: congestive cardiac failure (12 patients), embolism (8 patients), constitutional (3 patients), asymptomatic (2 patients) and tachyarrhythmia (1 patient). The diagnosis was confirmed by 2D echocardiography alone in thirteen patients and by a combination of echocardiography and angiography in thirteen patients. At operation the site of the tumour was left atrial in 24 patients and bi-atrial in two patients. All cases were confirmed by histology. All patients made a good post-operative recovery, although one patient survived a pulmonary embolus and one patient developed a deep venous thrombosis. There has been one late death (five months after surgery) from a cerebrovascular accident. Serial echocardiography has revealed one recurrence to date (8 years after surgery). The surgical incidence of these tumours in the Republic of Ireland over the study period was 0.5 atrial myxomas/million population/year. Although rare atrial myxomas are the most important cardiac tumours to diagnose as the results from surgery are excellent.

Adolescent↗
PubMed1993

Adenocarcinoma of the lung in association with chronic sarcoidosis.

Adenocarcinoma of the lung occurred three years after the diagnosis of pulmonary and cutaneous sarcoidosis. The combination of pulmonary sarcoidosis and carcinoma, which may present diagnostic difficulties is rarely reported. As with other fibrosing lung diseases, however, chronic fibrosing sarcoidosis may predispose to adenocarcinoma.

Adenocarcinoma↗
PubMed1991

Broncho-oesophageal fistula of infectious origin.

A case of end stage pulmonary destruction secondary to adult onset broncho-oesophageal fistula of infectious aetiology is presented. Advanced bronchiectatic damage to the pulmonary parenchyma may be avoided by the maintenance of a high index of suspicion and a systematic approach to the diagnosis of recurrent lower respiratory tract infections.

Adult↗