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Biomedical subjects

S O'Donoghue

Publications and source records attributed to S O'Donoghue.

At least 19 recordsLinked to original sources
PubMed2001

Levofloxacin induced polymorphic ventricular tachycardia with normal QT interval.

Polymorphic ventricular tachycardia (PVT) is a form of ventricular tachycardia characterized by QRS complexes that seem to change direction during the tachycardia. If associated with a prolonged QT interval, it is called torsades de pointes. In the absence of a congenital long QT syndrome, torsades is seen with certain drugs such as antiarrhythmic agents (Class IA, IC, III), psychotropic medications, antidepressants, antihistamines, and electrolyte disturbances. We report the first case of polymorphic ventricular tachycardia with normal QT interval associated with the oral use of levofloxacin in the absence of other etiologies known to cause these arrhythmias.

Anti-Infective Agents, Urinary↗
PubMed1997

Intratester and intertester reliability and criterion validity of the parallelogram and universal goniometers for active knee flexion in healthy subjects.

BACKGROUND AND PURPOSE: A new parallelogram goniometer was designed by the Rehabilitation Centre of the Royal Ottawa Health Care Group in 1983. The advantage of using such a goniometer is that the clinician is not required to estimate the joint axis of rotation when taking a measurement. The parallelogram goniometer has obtained a good intratester and intertester reliability when measuring active range of motion of hip abduction on eight individuals with hip pathologies. However, the validity of the parallelogram goniometer has not been examined. The purposes of this study were to examine the intratester and intertester reliability and the criterion validity of the parallelogram and universal goniometers for active knee flexion on healthy individuals. SUBJECTS: Sixty healthy university students (44 females and 16 males; mean age of 20.6 yrs.) participated to this study. METHODS: Measurements with the universal and parallelogram goniometers were taken in two different positions, the smaller and larger angles of active knee flexion. All measurements were taken by two trained testers. A radiograph was taken in both positions to serve as the 'gold standard'. The sequence of the measurements and radiographs were randomly selected. The intra and intertester reliability of both goniometers were established by calculating the intraclass correlation coefficients (ICCs) using the repeated-measures ANOVA. The criterion validity was examined by calculating Pearson product-moment correlation coefficients (tau) between each goniometric and radiologic measurements. A 0.05 level of significance was chosen for each statistical test. RESULTS: Intratester reliability ranged from good to excellent for the small angles (ICC = 0.85 and 0.87) and the large angles (ICC = 0.91 and 0.96) when using the parallelogram goniometer. Intertester reliability was fair for the small angles of flexion (ICC = 0.43 to 0.52) and good to excellent for the large angles of flexion (ICC = 0.82 to 0.88). The parallelogram goniometer was found to have greater validity when measuring the large angles of knee flexion (r = 0.73 and 0.77) compared to the small angles of knee flexion (r = 0.33 and 0.41). Similar results of reliability and validity were obtained with the universal goniometer. CONCLUSION: The results of this study have clinical importance. The use of the parallelogram goniometer was found to be as reliable and valid as the universal goniometer when measuring active knee flexion. However, the parallelogram goniometer offered clinicians the advantages of obtaining precise angular measurements with fewer adjustments, and a faster application technique. Further studies on the parallelogram goniometer are necessary among individuals presenting with altered range of motion at different joints.

Adult↗
PubMed1997

Sisyphus and prediction of protein structure.

The problem of predicting protein structure from the sequence remains fundamentally unsolved despite more than three decades of intensive research effort. However, new and promising methods in three-dimensional (3D), 2D and 1D prediction have reopened the field. Mean-force-potentials derived from the protein databases can distinguish between correct and incorrect models (3D). Inter-residue contacts (2D) can be detected by analysis of correlated mutations, albeit with low accuracy. Secondary structure, solvent accessibility and transmembrane helices (1D) can be predicted with significantly improved accuracy using multiple sequence alignments. Some of these new prediction methods have proven accurate and reliable enough to be useful in genome analysis, and in experimental structure determination. Moreover, the new generation of theoretical methods is increasingly influencing experiments in molecular biology.

Computers↗
PubMed1993

Effect of milrinone in human platelet shape change, aggregation and thromboxane A2 synthesis: an in vitro study.

Milrinone (MIL; a cAMP-specific phosphodiesterase type-III inhibitor), added in vitro to achieve concentrations below the therapeutic levels, inhibited agonist-induced platelet shape change (PSC). Arachidonic acid (AA)-induced PSC was significantly more inhibited by a combination of MIL and indomethacin (INDO; a cyclooxygenase inhibitor) than by either alone. PSC induced by 5-hydroxytryptamine was inhibited by MIL but not by INDO; and this effect of MIL was not augmented by INDO. Whole blood-platelet aggregation (WB-PA) and platelet-rich plasma aggregation induced by potent stimulators of thromboxane A2 (TXA2) synthesis such as AA and calcium ionophore and by less potent agonists (e.g. ADP and U46619) were inhibited by MIL at or near therapeutic concentrations. WB-PA induced by collagen was significantly more inhibited by the MIL and INDO combination than by either of these agents alone whereas with ADP-induced WB-PA no additional effect could be shown when both MIL and INDO were co-incubated. MIL and similar types of drugs may be of benefit in conditions associated with platelet hyperactivity and some of these effects may be enhanced by cyclooxygenase inhibitors.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1990

Automatic implantable cardioverter-defibrillator: is early implantation cost-effective?

The evaluation of survivors of sudden cardiac death with serial electrophysiologic studies involves a lengthy and expensive hospitalization, especially when an automatic implantable cardioverter-defibrillator is ultimately necessary. The cost efficacy of this conventional approach was therefore compared with direct implantation of a cardioverter-defibrillator after the first electrophysiologic study. Thirty-two survivors of sudden death who had inducible ventricular tachycardia during their initial electrophysiologic study underwent serial drug trials. At discharge 12 (37%) were taking an antiarrhythmic drug found to prevent induction of ventricular tachycardia and 20 underwent cardioverter-defibrillator implantation after serial drug trials proved ineffective. The average length of hospitalization for this group that had undergone serial drug testing was 20.2 +/- 9.3 days at an average cost of $48,900 +/- $31,600. Seven survivors of sudden death had no inducible ventricular tachycardia during their initial electrophysiologic study and underwent direct cardioverter-defibrillator implantation. Their average length of hospitalization was 12.6 +/- 6.2 days at an average cost of $40,400 +/- $8,300. It is concluded that automatic implantable cardioverter-defibrillator implantation as an early intervention is not more costly and indeed may be cost-effective compared with therapy guided by serial electrophysiologic testing. As antitachycardia devices become more versatile, long lived and easier to implant, earlier implantation is likely to compare even more favorably with drug therapy.

Anti-Arrhythmia Agents↗
PubMed1988

Reuse of pacing catheters: a survey of safety and efficacy.

We surveyed 12 medical centers with regard to the reuse of pacing catheters during electrophysiologic studies. The prevalence of superficial skin infections or bacteremia related to EP studies was extremely low, and was not significantly different in the catheter reuse group compared to the single use group. We conclude that catheter resterilization and reuse is safe and cost-effective.

Cardiac Catheterization↗
PubMed1983

Herpes simplex virus type II meningoencephalitis in an immunocompromised adult.

A 35-year-old man with chronic granulocytic leukemia had disseminated herpes simplex virus type II. Cerebrospinal fluid pleocytosis, aphasia, and an abnormal electroencephalogram suggested the diagnosis of meningoencephalitis. He was treated with adenosine arabinoside and recovered without clinically evident sequelae.

Adult↗
PubMed1983

Cigar and pipe smoking related to four year survival of coronary patients.

Six hundred and thirty-four male patients under 60 years who survived a first attack of unstable angina or myocardial infarction were followed for a period of four years. Details of initial and follow-up smoking habits were examined. Patients who continued to smoke cigarettes or cigars had an excess mortality compared with non-smokers, with those who stopped smoking, and with cigarette smokers who changed to pipe smoking. Pipe smokers who continued smoking the pipe had an observed mortality which was greater than that of the non-smokers, but the numbers were small and the results were not statistically significant. The effect of smoking habit on mortality was not influenced by two other determinants of prognosis: age and severity of initial attack. These results confirm that the long-term prognosis of patients after unstable angina or myocardial infarction may be significantly influenced by smoking habits. They are consistent with the hypothesis that cigar and pipe smoking may have an adverse effect after myocardial infarction but further studies are needed to corroborate the association between cigar and pipe smoking and prognosis of coronary heart disease.

Adult↗
PubMed1981

Unstable angina: natural history and determinants of prognosis.

One hundred one patients with unstable angina were treated conservatively without the routine use of beta receptor blocking agents, calcium antagonist drugs, anticoagulant agents or nitrates. Only two patients underwent arteriography and coronary arterial bypass surgery during hospitalization and one patient during the 1st year of follow-up study. The 28 day mortality rate was 4 percent and the total 1 year cardiac mortality rate 10 percent. Two patients died from carcinoma. The incidence rate of nonfatal myocardial infarction was 9 percent during the first 28 days and a further 3 percent for the 1st year. These results compare favorably with the immediate and 1 year prognosis reported from other studies using different treatment procedures, including modern intensive drug treatment and coronary arterial bypass surgery. Various factors studied during the acute stage of unstable angina were assessed in an effort to predict the immediate and long-term outcome. Only persistence of pain after admission to the hospital was found a significant indicator of an adverse prognosis. Modern medical treatment of unstable angina with beta receptor blocking agents, calcium antagonist drugs, anticoagulant agents, nitrates and antiarrhythmic agents is critically examined. The paucity of proper randomized controlled studies confirming the value of medication is underlined. There is little evidence to show that aggressive or intensive medical or surgical treatment is superior to a conservative approach to management in the coronary care unit. This approach includes bed rest until the pain has resolved, symptomatic drug treatment only, the minimal use of invasive investigations and careful risk factor intervention.

Adrenergic beta-Antagonists↗
PubMed1975

The evaluation of cotton twine as a new anti-inflammatory assay.

A new anti-inflammatory assay is described, utilizing a subcutaneously implanted elongated section of cotton twine to induce granuloma in rats. The cotton twine irritant is easily introduced under the abdominal skin and after seven days a well formed granuloma is established. The procedure works effectively for both steroidal and non-steroidal anti-inflammatory drug evaluation. Consistency of the cotton twine eliminates individual weighing of each section and uniformity in compactness affords reproducible results.

Animals↗
PubMedDate not supplied

Monophasic action potential recordings: evaluation of antiarrhythmic drugs.

The use of MAP recording techniques has been said to have bridged the gap between basic in vitro investigation of the transmembrane action potential and observations made in situ from the beating heart. With regard to antiarrhythmic agents, MAP recordings are particularly useful in evaluating drugs which prolong repolarization. The simultaneous measurement of MAP and ERP at the same site permits the comparison of drug effects on repolarization and refractoriness. The ability to safely and reliably record the MAP contributes importantly to the evaluation and classification of antiarrhythmic drug effects in vivo and may ultimately lead to more rational selection of drug therapy for individual patients. Antiarrhythmic drug effects demonstrated with MAP recordings have generally shown good agreement with the Vaughan Williams classification of electrophysiological actions. An important key to drug efficacy may be that some drugs prolong refractoriness beyond their effect on repolarization. Conversely, a potential explanation for proarrhythmia may lie in slowing of conduction without the concomitant protective effect of postrepolarization refractoriness. The phenomenon of use dependence, which has been demonstrated for many drugs, suggests why an agent that prevents induction of arrhythmia during programmed stimulation in the electrophysiology laboratory may not prevent spontaneous arrhythmia initiation at slower heart rates. The paramount task of clinical electrophysiology is the successful treatment of rhythm disturbances. The more detailed and quantitative evaluation of drug effects afforded by MAP recordings may ultimately result in the more effective use of antiarrhythmic drugs in general and to more precise tailoring of therapy for individual patients.

Action Potentials↗