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Biomedical subjects

Stephen O'Connor

Publications and source records attributed to Stephen O'Connor.

18 recordsLinked to original sources
PubMed2006

A systematic review and meta-analysis of treatments for aortic graft infection.

OBJECTIVE: We compared pooled estimates of event rates for amputations, conduit failures, reinfections, early mortalities, and late mortalities in patients with aortic graft infection who were treated by extra-anatomic bypass, rifampicin-bonded prostheses, cryopreserved allografts, or autogenous veins. METHODS: A systematic review was conducted of English language reports in MEDLINE back to 1985 and a meta-analysis was performed on the results. Studies were selected on the basis of medical subject headings aortic, graft, and infection, and also by a standardized and independent quality rating. Inclusion and exclusion criteria were met by 37 clinical studies. Pooled estimates of mean event rates for amputations, conduit failures, reinfections, early (< or =30 day) mortalities, and late (>30 days) mortalities were determined for each treatment modality. Tests of heterogeneity and sensitivity analyses were performed. RESULTS: Fixed effect analyses, derived after tests of heterogeneity, yielded overall pooled estimates of mean event rates for all outcomes combined of 0.16 for extra-anatomic bypass, 0.07 for rifampicin-bonded prostheses, 0.09 for cryopreserved allografts, and 0.10 for autogenous vein; a lower value signifies fewer overall events associated with the treatment modality. Overall, the robustness of our meta-analysis was demonstrated by the reasonable heterogeneity of pooled data from individual studies (Q statistic <25; P >.1 for all treatment outcomes across all modalities) and the limited variability of outcomes after sensitivity analyses. CONCLUSION: Although limited by the design of individual published studies whose data were pooled together in this meta-analysis, our results lead to questions concerning whether extra-anatomic bypass should remain the gold standard for treatment of aortic graft infection.

Antibiotics, Antitubercular↗
PubMed2005

Long-term efficacy of cryo catheter ablation for the treatment of atrial flutter: results from a repeat electrophysiologic study.

OBJECTIVES: We investigated the long-term efficacy of cryo ablation for treatment of atrial flutter. BACKGROUND: To our knowledge, no study has assessed the long-term efficacy of cryo ablation by assessing both symptom and conduction recurrence. METHODS: A total of 45 consecutive patients with symptomatic atrial flutter were ablated with a 7-F, 6-mm-tip, quadripolar cryo catheter (Freezor Xtra, CryoCath Technologies Inc., Kirkland, Canada). Electrophysiologic studies (EPS) were performed with diagnostic catheters. Cryo ablation was at -75 degrees C for 4 min, beginning at the inferior rim of the coronary sinus os and creating a posterior line to the Eustachian ridge. Safety, bi-directional isthmus block at intervention, and recurrence at three, six, and nine months post procedure were assessed. RESULTS: There were no adverse events reported. All patients were free of discomfort on cryo energy delivery. The acute success rate at intervention was 87%. Follow-up data from 39 acutely successful patients showed 27 (69%) without conduction recurrence on repeat EPS at three months, and none (0%) had symptom recurrence documented by Holter monitoring, electrocardiogram, and/or patient diary records at three, six, and nine months follow-up. CONCLUSIONS: Our experience with a new 7-F, 6-mm-tip, quadripolar cryo catheter yielded a fairly high success rate at intervention, an excellent safety profile, and a good chronic success rate in terms of symptom recurrence. However, further monitoring is necessary to determine whether all asymptomatic patients continue to remain free of symptoms, given the small pool of patients demonstrated to have conduction recurrence.

Aged↗
PubMed2005

Transcatheter cryoablation of tachyarrhythmias in children: initial experience from an international registry.

OBJECTIVES: We sought to describe the early pediatric experience of transcatheter cryoablation, and identify whether specific arrhythmia substrates and/or ablation locations were particularly suited to cryoablation. BACKGROUND: Radiofrequency (RF) ablation has become established therapy for pediatric tachyarrhythmias. However, challenges remain in terms of the safety and efficacy of RF ablation in specific locations; new methods may address these issues. METHODS: Prospective data were available for 64 patients age 13 +/- 4 (mean +/- SD) years undergoing cryoablation at 14 centers participating in the Cryocath International Patient Registry. Dysrhythmia duration was 5.0 +/- 4.2 years, with diagnoses of atrioventricular node re-entrant tachycardia (AVNRT) (n=30), anteroseptal (n=11), midseptal (n=5), or other (n=15) accessory pathway (AP) mediated AV re-entry, ventricular tachycardia (VT) (n = 3), and ectopic atrial tachycardia (EAT) (n=2). Two patients had more than one arrhythmia substrate. Transcatheter cryoablation was offered by cardiologist preference after written informed procedural consent of each patient and/or legal guardian. Cryomapping was performed at -30 degrees C and cryoablation was delivered with 4-min applications at -75 degrees C. RESULTS: Acute success was achieved in 45 of 65 (69%) cryoablation patients, with best success rates in AVNRT (83%) and right septal AP (75%), and lower success rates in other AP (43%), VT (66%), and EAT (0%). No device-related adverse events were reported. The success of radiofrequency (RF) ablation applied in 14 cryoablation failures was 4 of 4 for AVNRT patients, 1 of 1 for anteroseptal AP patients, 5 of 6 for other AP patients, 0 of 1 for VT patients, and 0 of 2 for EAT patients. CONCLUSIONS: Transcatheter cryoablation is a safe and well-tolerated alternative to RF ablation in pediatric patients on the basis of our initial experience. Success is highest in AVNRT and in substrates recognized as technically challenging or risky for RF ablation.

Adolescent↗
PubMed2005

AT1 receptor blockade prevents cardiac dysfunction after myocardial infarction in rats.

Myocardial infarction (MI) can induce severe alterations of contractile function that can, in turn, lead to heart failure. In a previous study, we have demonstrated that TNF-alpha was involved in cardiac contractile dysfunction 7 days after coronary artery ligation in rats. Since Angiotensin II type 1 (AT1) receptor can be involved in TNF-alpha production, we have investigated whether early short-term treatment with irbesartan, an AT1 receptor blocker, is able to limit TNF-alpha production within the heart and to improve cardiac function and geometry following MI in rats. Male Wistar rats were subjected to permanent coronary artery ligation and received either a placebo or irbesartan (50 mg/kg/day) per os daily from day 3 to day 6 after surgery. On day 7, cardiac TNF-alpha was significantly reduced in MI rats receiving irbesartan (p < 0.05). Moreover, irbesartan improved residual LV end-diastolic pressure under both basal conditions and after volume overload (p < 0.01). In addition, a significant leftward shift of the pressure-volume curve in the irbesartan-treated group was found versus placebo. Finally, infarct expansion index was also significantly improved by irbesartan (p < 0.01). In conclusion, early, short-term AT1 receptor blockade limits post-infarct cardiac TNF-alpha production and diminishes myocardial alterations observed 7 days after MI in the rat.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2003

Correlating structure with fluorescence emission in phase-separated conjugated-polymer blends.

Blends of conjugated polymers are frequently used as the active semiconducting layer in light-emitting diodes and photovoltaic devices. Here we report the use of scanning near-field optical microscopy, scanning force microscopy and nuclear-reaction analysis to study the structure of a thin film of a phase-separated blend of two conjugated polymers prepared by spin-casting. We show that in addition to the well-known micrometre-scale phase-separated morphology of the blend, one of the polymers preferentially wets the surface and forms a 10-nm-thick, partially crystallized wetting layer. Using near-field microscopy we identify unexpected changes in the fluorescence emission from the blend that occurs in a 300-nm-wide band located at the interface between the different phase-separated domains. Our measurements provide an insight into the complex structure of phase-separated conjugated-polymer thin films. Characterizing and controlling the properties of the interfaces in such films will be critical in the further development of efficient optoelectronic devices.

Crystallization↗
PubMed2002

Rating outlets for health care management research: an update and extension.

The ongoing discussion of our intellectual community requires that occasionally an effort be made to value the outlets for our research and erect guideposts for our colleagues to signal important contributions to our discipline. This study extends previous work through a survey sent to 1,254 academics involved in health care management research that asked them to rate 54 potential outlets for their research. Ratings were made on journal knowledge, quality, and relevance. Two survey waves resulted in 389 responses (adjusted response rate 37.8 percent). For quality and relevance, journal rankings were separated into A, B, and C categories. The results correlated strongly with the two previous studies in this area. This study extends previous research and provides a categorization of journals on knowledge, quality, and relevance that may assist in faculty performance evaluation and identification of appropriate outlets for manuscripts.

Attitude of Health Personnel↗
PubMedDate not supplied

The interview dance: getting what you ask for.

Interviewing potential employees is hardly a science, but what we ask and how we ask it can often elicit the information we need about a prospective employee. Conversely, irrelevant questions can often backfire on us.

Humans↗
PubMedDate not supplied

Employee turnover: measuring the malady.

One measure of an organization's value to its employees is turnover. But how do you know if your employees are wondering if the grass is greener elsewhere? Scott Badler in his book What's So Funny about Looking for a Job? suggests a quick quiz to find out.

Attitude of Health Personnel↗
PubMedDate not supplied

Nurse retention: outrunning the bear.

Did you hear the one about the hospital CEO who was hiking in the forest with the director of nursing? As they were heading down a trail, suddenly a bear jumped out of a bush and started chasing them. Both hikers started running for their lives when all of a sudden the CEO stopped, sat down on a rock and started to put on running shoes. The director of nursing said, "What are you doing? You can't outrun a bear!" The CEO replied, "I don't have to outrun the bear. I only have to outrun you."

Humans↗
PubMedDate not supplied

Look before you leap into a hire decision.

An executive had to take a ferry across the river every morning to get to work. One morning he woke up and found that the electricity had gone off in the middle of the night. With no idea what time it was, he dressed and ate as quickly as he could and ran for the dock.

Administrative Personnel↗