Debt crisis ahead for Irish medical students.

Internationally medical student debt is a cause of concern. A survey of medical students in UCC (response rate of 191 representing 35% of the EU student cohort) reveals that 34 (26%) of direct entry medicine (DEM) students and 36 (61%) graduate entrants (GEM) have a loan with an anticipated average debt of Euro17,300 and Euro80,000 on graduation respectively. Fifty-three (90%) graduate entrants and 75 (57%) direct entrants revealed that they often worry about their current financial situation. Fifty-three (28%) of students have a part-time job and many were concerned about the degree to which this conflicted with their academic workload. 118 (89%) of school leavers and 48 (81%) graduates received financial assistance from their families to fund their college expenses. Student responses recommended the introduction of a government supported low interest rate loan and other incentives to help service high levels of debt associated with medical education.

Intracardiac echocardiographic guidance during microwave catheter ablation.

The purpose of this study was to explore the potential of intracardiac echocardiography in monitoring lesion formation and assisting with the assessment of ablative lesions using microwave energy. Microwave energy is a promising modality for catheter ablation. Because microwave lesions may have considerable variability in dimension, the ability to assess them may be particularly useful. One hundred twenty-five microwave lesions were created in vitro in ovine left ventricles. Correct assessment of catheter-endocardial contact was possible in virtually all cases. Intracardiac imaging always identified correctly whether or not an ablation was performed. During ablation, gas formation was observed in all instances. Sensitivity, specificity, and predictive values for identification of ablation lesions were 88% to 92%. Although the correlations with pathology for lesion dimensions were relatively poor, intracardiac imaging had a predictive accuracy of 80% to 85% to discriminate small from large lesions. Intracardiac guidance for microwave ablation is useful for verifying tissue-electrode contact, monitoring lesion formation, and localizing lesions. It is also a useful tool for the assessment of lesion size. These attributes, combined with the ability to facilitate transseptal catheterization and to identify complications such as hemopericardium, make intracardiac echocardiography a potentially useful method for guiding microwave ablation of arrhythmic foci.

Arrhythmogenic right ventricular dysplasia: clinical results with implantable cardioverter defibrillators.

Arrhythmogenic right ventricular dysplasia is a clinical entity characterized by fatty infiltration of the right ventricle and left bundle morphology ventricular tachycardia occurring in young patients. The most common cause of death is tachyarrhythmic. Pharmacological and nonpharmacological therapies, including implantable cardioverter defibrillators, have been used to treat the arrhythmias. However, right ventricular endocardial leads in this population may be associated with an increased risk of perforation and suboptimal sensing and defibrillation efficacy due to the diseased right ventricle. We report on 12 patients with arrhythmogenic right ventricular dysplasia who were treated with implantable cardioverter defibrillators. The mean age was 31 +/- 9 years (range 15-48). Patients presented with presyncope (5), syncope (4), or cardiac arrest (3). All patients had electrocardiographic abnormalities characteristic of the condition. During programmed electrical stimulation nine patients had sustained ventricular tachycardia, while three patients had no inducible arrhythmia. Transvenous leads were placed in nine patients. In these patients pacing thresholds were significantly higher, R-wave amplitudes were significantly lower and defibrillation thresholds were not significantly different than in a cohort of patients without right ventricular dysplasia. There were no acute or chronic complications of right ventricular lead placement. Follow-up averaged 22 +/- 13 months (range 1-45). There was one sudden death at 1 month of follow-up. Of the 12 patients, 8 have had appropriate therapy delivered by the implantable defibrillator. Six patients are currently on sotalol to reduce the frequency of implantable defibrillator discharges. In conclusion, implantable cardioverter defibrillators with nonthoracotomy leads are feasible and safe in patients with arrhythmogenic right ventricular dysplasia. The frequency of appropriate therapy is high, supporting the use of implantable cardioverter defibrillators in this population.

Pulsing microwave energy: a method to create more uniform myocardial temperature gradients.

Microwave energy has been proposed as a possible technique to create large myocardial lesions. Achieving a uniform myocardial temperature gradient during microwave ablation may prevent excessive endocardial temperatures while maintaining temperatures at depth. The goal of the current study was to examine the ability of microwave (MW) pulsing to achieve a more uniform myocardial temperature gradient. Using an in-vitro ovine endocardial model, we measured tissue temperature at 0.5-mm, 2.0-mm, and 3.5-mm depths in a circulating saline bath. MW energy was delivered at 20 W at 915 MHz for 30 seconds. Pulse configurations of 1 second on-1 second off, 3 seconds on-3 seconds off, and 5 seconds on-5 seconds off, with 30 seconds of total MW time were compared with 30-seconds continuous. Maximum temperatures at 0.5 mm were significantly lower at 63.2 +/- 5.89 degrees C for the 1-second pulse compared with 83.5 +/- 7.31 degrees C for the continuous-energy delivery. Pulse configurations 3 seconds on-3 seconds off and 5 seconds on-5 seconds off also resulted in a significantly lower surface temperature than continuous-energy delivery. However, temperature at the 2.0-mm and 3.5-mm depth created by the pulsing delivery were similar to those achieved during continuous-energy delivery. Thus, microwave pulsing achieves a lower endocardial temperature and results in a more uniform temperature gradient. These techniques may prevent the excessive endocardial damage that may result in an increased risk of thrombus formation and embolization.

Structure and function of the vertebrate magnetic sense.

Some vertebrates can navigate over long distances using the Earth's magnetic field, but the sensory system that they use to do so has remained a mystery. Here we describe the key components of a magnetic sense underpinning this navigational ability in a single species, the rainbow trout (Oncorhynchus mykiss). We report behavioural and electrophysiological responses to magnetic fields and identify an area in the nose of the trout where candidate magnetoreceptor cells are located. We have tracked the sensory pathway from these newly identified candidate magnetoreceptor cells to the brain and associated the system with a learned response to magnetic fields.

Antitachycardia pacing and low-energy cardioversion for ventricular tachycardia termination: a clinical perspective.

When incorporated into tiered therapy implantable cardioverter defibrillators (ICDs), antitachycardia pacing (ATP) techniques have proved useful for termination of sustained monomorphic ventricular tachycardias (VT) and have the advantages of rapid delivery, absence of patient discomfort, and minimal battery drain. The efficacy of low-energy cardioversion (LEC) is similar to that of pacing techniques for VT termination, but LEC has the disadvantages of patient discomfort, atrial proarrhythmia, and greater battery drain compared with ATP. Acceleration of VT occurs with similar frequency with each technique. Neither technique should be used without back-up defibrillation capability in an ICD. VT termination algorithms are currently empiric and require repetitive arrhythmia induction and trials of ATP or LEC. Future studies of the risk and benefits of each technique are likely to define optimal programming strategies in tiered therapy ICDs.

Role of nitric oxide-related inhibition in intestinal function: relation to vasoactive intestinal polypeptide.

This study examined the role of nitric oxide (NO) in tonic inhibition of motor activity in isolated, perfused canine ileal segments. Brief addition of N omega-nitro-L-arginine methyl ester (L-NAME) to the perfusate caused, after a delay, a concentration-dependent persistent increase in tonic and phasic activity of circular muscle. This increased motor activity was prevented or reversed by addition of L- but not D-arginine to the perfusate. Removal of Ca2+ or addition of 10(-7) M omega-conotoxin (GVIA) to the perfusate markedly reduced this response. The motor activity induced by L-NAME was accompanied by loss of distal inhibition and enhanced excitation to low-frequency field stimulation. L-NAME infusion significantly reduced tonic vasoactive intestinal polypeptide (VIP) output, sodium nitroprusside increased VIP output, but L-arginine infusion did not restore VIP output. Atropine (10(-7) M) and/or hexamethonium (10(-4) M) reduced the motor response to L-NAME by 75%. Atropine reduced and hexamethonium nearly abolished VIP output. We conclude that there is tonic Ca(2+)-dependent NO output from perfused intestinal segments dependent on nerves with N-Ca channels, that NO acts to inhibit muscle directly and by inhibiting release of excitatory mediators, and that this output is the primary inhibitory determinant of contractile activity.

Red kidney bean poisoning in the UK: an analysis of 50 suspected incidents between 1976 and 1989.

Between July 1976 and February 1989, 50 incidents of suspected red kidney bean poisoning were reported in the UK. Nine incidents in which nausea, vomiting and diarrhoea developed within 1-7 h of ingestion, were confirmed by the detection of haemagglutinin in the beans. The diagnosis was made on a further 23 incidents on the basis of symptoms, incubation time and the description of preparation of beans prior to consumption. The haemagglutinin (lectin), which occurs naturally in the red kidney bean, is inactivated by thorough cooking of well soaked beans. In many of the outbreaks reported the implicated beans were consumed raw or following an inadequate heat process.

Legionella in Dublin hospital water supplies.

An environmental survey was carried out which consisted of periodic and random sampling of water tanks and showers in two large Dublin hospitals. Of the samples 5.3% yielded Legionella bacteria. Legionella pneumophila of serogroups 3, 5 and 6 were isolated from these sites with viable counts ranging from 3.0 x 10(2) - 2.5 x 10(3) c.f.u./litre. The implementation of periodic sampling may, however, not be a worthwhile exercise unless an environmental site has been associated with cases of legionellosis. Emphasis should be placed on the prevention of contamination of environmental sites with legionellae and on the development and implementation of protocols and procedures for the isolation of legionellae to gain the necessary expertise should an epidemiological survey be required.

Legionella: an infrequent cause of adult community acquired pneumonia in Dublin.

The commonest infectious agents identified in community acquired pneumonia (CAP) amongst 50 patients admitted to a Dublin hospital were Streptococcus pneumoniae and Haemophilis influenzae. Legionella pneumophila pneumonia occurred in only one patient who acquired infection abroad. A serological screen of blood bank donors and renal transplant recipients failed to detect antibody to Legionella pneumophila supporting the clinical findings of a low prevalence of infection in this community. It is concluded that initial antibiotic therapy for patients with CAP need not routinely include cover for Legionella.

Laboratory and epidemiologic assessment of a recent influenza B outbreak.

A viral surveillance system in Nashville detected an outbreak of influenza B that occurred between January and March 1986. Paired sera from 32 individuals with culture-documented influenza B illness were tested using three serologic assays. Enzyme-linked immunosorbent assay (ELISA) using purified hemagglutinin-neuraminidase and plaque neutralization detected a seroresponse in 69% and 66% of these individuals, respectively. These assays were superior to hemagglutination inhibition, which detected a 41% seroresponse. ELISA was perferred because of cost and ease of performance. A group of 286 individuals, aged 1-65 years, was studied more extensively including serologic assessment before and after the influenza B outbreak. Historical information and viral throat cultures were obtained from those with influenza-like illness during the epidemic. An influenza B infection rate (seroresponse and/or positive culture) of 31% and illness rate (infection with flu-like symptoms during the epidemic period) of 13% was demonstrated using these methods. Pre-epidemic mean serum ELISA IgG titers were lower in those with, versus those without, evidence of subsequent influenza B illness (1,541 vs. 4,311, P = .0026). Children less than or equal to 15 years of age were infected more frequently than adults (44% vs. 28%, P = .04). Fever greater than or equal to 101 degrees F was reported more frequently with influenza B than non-B illness (43% vs. 18%, P = .03). These data are useful in preparing for future epidemiologic studies of influenza B and demonstrate the value of and need for standardization of ELISA as a serologic assay for influenza B.

Biased resonance circuits for electrooptic digital deflectors.

A number of circuits for electrooptic digital deflectors is presented. These circuits minimize power dissipation by utilizing the novel technique called biased resonance. This technique is based on the coincidence of zero points of a raised cosine and its derivative. Test results are reported for one circuit that operated at 2200 V, with a load capacitance of 200 pF, and at greater than 100 k baud rate. Dissipation for this breadboard model was 10 W. Other circuits are shown; their advantages and disadvantages are discussed. Also discussed are some future switching device requirements.