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Although the exact mechanism that makes bupropion hydrochloride (Zyban®) effective as a smoking cessation aid has not been fully elucidated, studies have found that bupropion and nicotine share behavioural and neurophysiological properties suggesting that bupropion might serve as a substitute for nicotine. In fact, bupropion prompts nicotine-appropriate responding in operant and Pavlovian drug discrimination studies with rats. A majority of the literature examining this substitution pattern has been done with an operant paradigm. The present research extended this literature by further characterising the behavioural and neuropharmacological properties underlying the substitution for a nicotine conditioned stimulus (CS). Examination of the dose-effect function and temporal dynamics of this substitution pattern showed that bupropion (20 mg/kg) produced conditioned responding similar to nicotine (0.4 mg base/kg) (ED50 = 9.9 mg/kg) at 15 and 30 min after injection and partially substituted 5 and 60 min post-injection. Bupropion produced a pattern of conditioned responding similar to nicotine during a 60-min extinction test. Additionally, it has been hypothesised that bupropion and nicotine have an overlapping dopaminergic mechanism. We tested the effects of bupropion pretreatment, the nicotine dose-effect function and the ability of dopamine antagonist to block the substitution of bupropion for nicotine. Pretreatment with doses of bupropion that did not substitute for the nicotine stimulus (5 and 10 mg/kg) did not affect nicotine-conditioned responding; pretreatment with 20 mg/kg attenuated nicotine-evoked responding. Pretreatment with the dopamine antagonists SCH-23390 and eticlopride blocked the substitution. Finally, S,S-hydroxybupropion, the major metabolite of bupropion in humans, did not substitute for the nicotine CS. [ABSTRACT FROM AUTHOR]

The article discusses the usefulness of various calculations for the evaluation of haemodynamic abnormalities among patients with congenital heart disease. It states that a number of calculations could be performed among patients with congenital heart disease whose communication between the two sides of the heart or between the pulmonary artery and aorta allows the existence of a shunt. It says that the assessment of pulmonary blood flow and cardiac output is significant to various situations.

Surgical treatment of various septal defects has been long established. With the advances in transcatheter therapy dilatation techniques for valvular stenosis and vascular obstruction have become established procedures. Closure of septal defects in the catheterization laboratory has also been introduced; some of these have come into regular use in current practice. In 1967, Porstmann et al reported the use of Ivalon plug to close patent ductus arteriosus (PDA). Since then, several devices have been used including Rashkind PDA ocluder (not being used now), Gianturco coils, detachable coils (for small PDA), CardioSEAL and other umbrella devices and Amplatzer PDA occluder. Closure rates vary from 95-98% in most series, however, some of these devices are very expensive, more so, when compared to the cost of surgical ligation of PDA. Catheter closure of secundum atrial septal defect (ASD) has also been done by various devices like clamshell device, Sideris Buttoned device, ASDOS device, Amplatzer device and cardioSEAL. So far no device has been accepted as ideal for every case, however, Amplatzer device has been used most extensively. Issues such as completeness of endothelialisation, incidence of late arrhythmias, endocarditis remain uncertain. However, in select population of ASD cases with a central secundum defect, device closure is being used increasingly. Device closure of ventricular septal defect remains challenging and controversial and is probably available to a small group of children with defects that are difficult to close surgically and involve higher risk. [ABSTRACT FROM AUTHOR]

Two main theories exist for the explanation of univentricular hearts. One states that the bulboventricular septum becomes realigned to form the interventricular septum, and that univentricular hearts are a consequence of failure of this realignment. The other states that bulboventricular and interventricular septa are different structures, and that the univentricular heart results from failure of formation of the posterior interventricular septum. Four hearts are described in which both the posterior septum and an anterior bulboventricular septum are present. In each heart, therefore, the right ventricular sinus is separated both from the left ventricular sinus and from a discrete outlet chamber which supports the pulmonary artery. It is argued that these findings militate strongly against theories proposing reorientation of the bulboventricular septum to form the definitive interventricular septum. They support strongly the concept that the definitive right ventricle is formed in part from the bulbus and in part from the primitive ventricle. On the basis of these findings, it is suggested that the distinctive feature of the univentricular heart is absence of the posterior septum. Such hearts can properly be termed 'primitive ventricle'. It is also suggested that hearts with atretic or straddling valves should be included within this category. [ABSTRACT FROM PUBLISHER]

Seven cases of transposition with an unusually posterior aorta and mitral-aortic fibrous continuity are described. The cases are similar to four cases published by Van Praagh et al. in 1971. The use of the term 'p' transposition is suggested to distinguish this unusual form of transposition from cases with a subaortic conus ('d' and 'l' transposition). The use of the term 'transposition' is considered justifiable on both semantic and morphogenetic grounds and a possible common embryological mechanism for all forms of transposition is discussed. [ABSTRACT FROM PUBLISHER]

Four patients are described with a recently recognized variant of double outlet right ventricle. Clinical examination favoured tetralogy of Fallot, but the chest X-ray suggested corrected transposition. Catheterization and angiocardiography showed that the aorta was to the left of the main pulmonary artery, and both arose from a normally positioned morphological right ventricle. Egress of blood from the left ventricle was through a subaortic ventricular septal defect. In all patients severe pulmonary stenosis was present and the right coronary artery ran an anomalous course anterior to the pulmonary valve ring. Two children had successful total correction, and one a palliative Blalock-Taussing shunt. Necropsy material from the fourth patient allowed confirmation of the ventricular morphology and the conducting tissued was examined. In corrective surgery, blood from the left ventricle was rerouted into the aorta by an intraventricular baffle. Pulmonary stenosis was relived by infundibulectomy and outflow tract patch. [ABSTRACT FROM PUBLISHER]

The article examines the background and development of the surgery for congenital heart disease. Rapid developments gave rise to great changes in the diagnosis, surgery and prognosis of this disease. Physicians James Brown and Helen Taussig made the first major attempt to produce a comprehensive account of the clinical features of congenital heart disease. Taussig provides much of the drive and stimulus as a result of the pediatric cardiology and cardiac surgery that flourished.