EuroQol: the current state of play

The EuroQol Group first met in 1987 to test the feasibility of jointly developing a standardised non-disease-specific instrument for describing and valuing health-related quality of life. From the outset the Group has been multi-country, multi-centre, and multi-disciplinary. The EuroQol instrument is intended to complement other forms of quality of life measures, and it has been purposefully developed to generate a cardinal index of health, thus giving it considerable potential for use in economic evaluation. Considerable effort has been invested by the Group in the development and valuation aspects of health status measurement. Earlier work was reported upon in 1990; this paper is a second 'corporate' effort detailing subsequent developments. The concepts underlying the EuroQol framework are explored with particular reference to the generic nature of the instrument. The valuation task is reviewed and some evidence on the methodological requirements for measurement is presented. A number of special issues of considerable interest and concern to the Group are discussed: the modelling of data, the duration of health states and the problems surrounding the state 'dead'. An outline of some of the applications of the EuroQol instrument is presented and a brief commentary on the Group's ongoing programme of work concludes the paper.

Pharmacodynamics of ZM 241385, a potent A2a adenosine receptor antagonist, after enteric administration in rat, cat and dog

4-(2-[7-Amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5] triazin-5-ylamino]ethyl)phenol (ZM 241385) is currently the most selective for the A2a adenosine receptor antagonist. This paper describes the in-vivo activity of ZM 241385 after administration by both oral and intraduodenal routes. In conscious spontaneously hypertensive rats, ZM 241385 (1-10 mg kg-1) selectively attenuated the mean arterial blood pressure response produced by exogenous adenosine (1 mg kg-1 min-1, i.v.) by up to 45% after oral administration. Activity of ZM 241385 was maintained for at least 6 h after 3 and 10 mg kg-1 (p.o.). In conscious normotensive cats, ZM 241385 attenuated the blood pressure responses to adenosine (0.6-1.0 mg kg-1, i.v.) by 94% after 10 mg kg-1 (p.o.) and by up to 74% after 0.3 mg kg-1 (i.v.). Duration of action of ZM 241385 up to 12 h (36% inhibition) was observed after 3 mg kg-1 (p.o.). In anaesthetized dogs and cats, ZM 241385, after intraduodenal administration (1-10 mg kg-1), produced a rapid (dose ratio 100-fold 15 min after administration of 10 mg kg-1 in the cat) and prolonged (dose ratio of 14 at 6 h after administration of 10 mg kg-1) attenuation of the vasodilatation responses to adenosine receptor stimulation. When administered by this route ZM 241385 was six times more potent than theophylline in the cat and at least twice as potent as theophylline in the dog. In conclusion, ZM 241385 is a potent, selective A2a adenosine receptor antagonist which is orally active, with a good duration of action by the enteric route in cat, rat and dog. It could therefore be used to evaluate the role of adenosine A2a receptors in the action of adenosine in-vivo.

The yield of head-up tilt testing is not significantly increased by repeating the baseline test

BACKGROUND AND HYPOTHESIS

Head-up tilt is widely used in evaluating patients with syncope. Data suggest that baseline tilt without isoproterenol is associated with few (< or = 10%) positive results in normals. However, there is considerable day-to-day variability in patients with syncope, resulting in low reproducibility. We hypothesized that repeating the baseline tilt would increase the total number of positive responses.

METHODS

In all, 193 patients with syncope of unknown etiology prospectively underwent serial baseline tilt (Tilt-1 and Tilt-2) at 70 degrees for 25 min on two consecutive days.

RESULTS

Of 193 patients, 39 (20%) had a positive Tilt-1. Of these, 19 had a positive Tilt-2, (positive concordance rate: 19/39 = 49%). Of 154 patients with a negative Tilt-1, 145 had a negative Tilt-2 (negative concordance rate: 142/151 = 94%). Only 9 of 154 patients (6%) with a negative Tilt-1 had a positive Tilt-2. Thus, the yield increased from 20% (39/193) after Tilt-1, and to 25% (48/193) after Tilt-1 plus Tilt-2, p = NS.

CONCLUSIONS

(1) Reproducibility of a positive Tilt-1 is moderate. (2) Reproducibility of a negative Tilt-1 is high. (3) Repetition of tilt in patients with a negative Tilt-1 does not significantly increase the number of positive results.

In vivo characterisation of ZM 241385, a selective adenosine A2A receptor antagonist

The in vivo characterisation of ZM 241385 (4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-+ ++ylamino] ethyl)phenol), a novel, non-xanthine, selective adenosine A2A antagonist is described. In anaesthetised dogs ZM 241385 (i.v.) was 140-fold more potent in attenuating vasodilator responses to exogenous adenosine in the constant flow perfused hind limb than the bradycardic effects. In pithed rats in which blood pressure was supported by angiotensin II infusion, ZM 241385 (10 mg kg-1, i.v.) did not inhibit the hypotensive or bradycardic effects of the A3/A1 receptor agonist N(6)-2-(4-amino-3-iodophenyl)ethyladenosine (APNEA). In conscious spontaneously hypertensive rats, ZM 241385 (3-10 mg kg-1, p.o.) selectively attenuated the mean arterial blood pressure response produced by exogenous adenosine. No inhibition of the bradycardic effects of adenosine was observed following these doses of ZM 241385. The results indicate that ZM 241385 can be used to evaluate the role of adenosine A2A receptors in the action of adenosine in vivo.

Malfunction of implantable cardioverter defibrillators placed by a nonthoracotomy approach: frequency of malfunction and value of chest radiography in determining cause

OBJECTIVE

The purpose of this study was to determine the frequency of system malfunction in patients with nonthoracotomy implantable cardioverter defibrillators and to assess the role of chest radiography in detecting and determining the cause of malfunction.

MATERIALS AND METHODS

The study population consisted of 300 consecutive patients in whom implantable cardioverter defibrillators were implanted using an initial nonthoracotomy approach between September 1990 and October 1994. Transvenous electrodes were placed via the subclavian or cephalic vein under local anesthetic. Intraoperative testing, pulse generator implantation, and, if necessary, subcutaneous patch or extrapericardial patch placement via thoracotomy were done in the operating room under general anesthetic. Follow-up consisted of routine device interrogation every 2-3 months and annual chest radiography. Chest radiographs were obtained more often if patients were symptomatic or if results of device interrogation were abnormal.

RESULTS

Patients were followed up for a mean +/- SD of 19 +/- 14 months following implantation. Implantable cardioverter-defibrillator malfunction occurred in 17 patients (6%) during the follow-up period. Of these, 12 (71%) had component abnormalities on chest radiographs. Patients with radiographically apparent implantable cardioverter-defibrillator abnormalities presented in two discrete time periods after device implantation, early (mean, 35 +/- 14 days) and late (mean, 18 +/- 5 months).

CONCLUSION

Malfunction of nonthoracotomy implantable cardioverter-defibrillator systems develops infrequently after device implantation. In most cases, the cause can be identified on chest radiographs.

IgH and L chain variable region gene sequence analyses of twelve synovial tissue-derived B cell lines producing IgA, IgG, and IgM rheumatoid factors structure/function comparisons of antigenic specificity, V gene sequence, and Ig isotype

In the present study, the complete sequences of the Ig H and L chain variable region genes of twelve RF+ B cell lines from two patients with RA were analyzed. Seven of the RF-producing B cells used VH3 family genes, four used VH4 genes, and one a VH1 gene. All but two of the cell lines expressing VH3 genes utilized different family members; among the VH4-expressing cells, a more restricted pattern was noted. V kappa gene use was restricted to the V kappa I and III families; V lambda gene use was more diverse, involving five different families. Computer comparisons of the expressed VH genes with their presumed germline progenitors indicated significant differences in every instance; eight of the corresponding VL genes also were significantly different. In many cases, assignment of the germline D segment(s) incorporated into the rearranged VH genes was impossible. These differences from the germline gene segments indicated the extensive changes induced by rearrangement, enzymatic activities, and somatic mutation. In hopes of defining a structural reason for the disparate antigen specificities of these cells, the CDR3 amino acid sequences of the multi- vs. the mono-reactive RF-producers were compared. Although CDR3 length was not appreciably different between these two sets of mAb, a greater than two-fold increase in charged amino acids was found in the H chain CDR3 of the multireactive RF. This relationship did not exist for the L chain CDR3. Thus, these sequence data indicate the use of a broad base of Ig V gene segments that have undergone extensive diversification. Based on the localization of R substitutions in the CDR of most of the V genes studied, the diversification appears to be antigen driven and selected. The significance of these findings for the evolution of these B cell clones into isotype-switched producers that are heterogeneous for antigen specificity (mono- vs. multi-reactivity) is discussed.

Implantation of transvenous nonthoracotomy cardioverter-defibrillator systems in patients with permanent endocardial pacemakers

Among 177 patients in whom a nonthoracotomy approach was initially used to implant a cardioverter-defibrillator system, 11 (6%) patients also received a separately implanted permanent pacemaker. The main problem encountered in these patients were previously implanted unipolar pacemakers (n = 3) and ventricular pacing leads positioned at the right ventricular apex, the latter interfering with optimal placement of the tripolar implantable cardioverter-defibrillator (ICD) lead (n = 9). The approaches used to solve these problems were individualized and included placement of the ICD sensing lead at the right ventricular outflow tract (n = 3), initial placement (n = 1) or subsequent repositioning (n = 2) of the right ventricular pacing lead at the outflow tract, upgrade from unipolar to bipolar systems (n = 2), reprogramming from the DDD to AAI mode (n = 2), inactivation of the pacemaker (n = 1), and simultaneous placement of a single-chamber atrial pacemaker with the ICD lead (n = 2). These revisions fulfilled the pacing needs in each patient and prevented unfavorable sensing interaction between the two systems.

Three-year outcome of a nonthoracotomy approach to cardioverter-defibrillator implantation in 189 consecutive patients

To date, no long-term clinical data have been published in patients undergoing a nonthoracotomy approach to cardioverter-defibrillator system implantation. In the present report, 189 consecutive patients prospectively underwent a standardized approach to cardioverter-defibrillator system implantation in which the nonthoracotomy configurations were tested first. If satisfactory defibrillation thresholds were not obtained, thoracotomy was performed during the same intraoperative session. A nonthoracotomy system was successfully implanted in 149 of 189 patients (79%), with a higher success rate (90%) observed in patients who had more recent implantations. The overall rate of complications associated with these systems was low (11%). Over a mean follow-up of 12.5 +/- 9.3 months, 17 patients (9%) died. Three-year total, cardiac, and sudden death-free actuarial survival for all patients was 83 +/- 11%, 88 +/- 7%, and 94 +/- 2%, respectively. Three-year sudden death-free actuarial survival was higher in the nonthoracotomy than in the thoracotomy patients (97 +/- 2% vs 87 +/- 6%, p = 0.047), although total survival was similar (77 +/- 11% vs 83 +/- 7%, p = 0.77). These data suggest that a majority of patients (> 80%) requiring a cardioverter-defibrillator system can undergo implantation using a nonthoracotomy approach. Patients receiving nonthoracotomy systems have 3-year outcomes comparable to those implanted via thoracotomy. If these results are maintained, a nonthoracotomy approach will supplant thoracotomy-implanted systems as the preferred method because of the simpler implant procedure and lower overall cost involved.

Plant defences against mammalian herbivores: are juvenile Acacia more heavily defended than mature trees?

Juvenile trees are expected to be more heavily defended against browsing mammals than mature plants. Juvenile and mature trees of Acacia tortilis and A. nilotica occurring at Nylsvley, Northern Transvaal, were quantitatively compared in terms of some potential chemical and physical defences. Neither species showed any significant difference between juvenile and mature trees in terms o f total polyphenol content, condensed tannin content, protein precipitating ability or protein content in leaves. Both species showed age-class differences in spinescence. In A. nilotica, thorns on branch tips were longer and more closely spaced and leaves were smaller in juveniles than in adults. Hence juveniles of this species appear to be physically more heavily defended than mature plants. In A. tortilis, curved thorns were longer, but straight thorns were shorter than in mature trees. There was no difference between age classes in overall thorn density, but juveniles had a higher curved to straight thorn ratio. It is not obvious what the effects of these differences might be on mammalian browsers.

Myocardial infarction and purine transport inhibition in anaesthetised ferrets

The potential cytoprotective effect of the purine transport inhibitor S-(p-nitrobenzyl)-6-thioinosine (NBTI) in a model of myocardial ischaemia and reperfusion was investigated in the anaesthetised ferret. The left anterior descending coronary artery (LAD) was occluded for 90 min, producing ischaemia in 53 +/- 3% of the left ventricular free wall, followed by 240 min reperfusion. NBTI (0.5 mg kg-1, i.v.) was given prior to ischaemia or prior to reperfusion. In addition the effect of purine transport inhibition was investigated in animals subjected to ischaemia without reperfusion. NBTI reduced infarct size from 84.0 +/- 1.7 to 71.4 +/- 3.7% of the area at risk (P < 0.05) when given prior to occlusion of the LAD. NBTI was ineffective however when given 15 min prior to reperfusion. NBTI had no effect upon infarct size produced by ischaemia without reperfusion. The effect of NBTI was independent of significant changes in myocardial blood flow during ischaemia and reperfusion or upon neutrophil infiltration.

Determinants of successful nonthoracotomy cardioverter-defibrillator implantation: experience in 101 patients using two different lead systems

OBJECTIVES

This study was conducted to identify the determinants of successful nonthoracotomy cardioverter-defibrillator implantation.

BACKGROUND

Until recently, either median sternotomy or thoracotomy was necessary to implant the electrodes used for internal cardioverter-defibrillator systems. A number of manufacturers have developed nonthoracotomy lead systems comprising two transvenous coil electrodes and a subcutaneous patch electrode. At present, the factors associated with the success or failure of a nonthoracotomy approach are unknown.

METHODS

A total of 101 consecutive patients requiring a cardioverter-defibrillator underwent an initial nonthoracotomy approach. Factors associated with successful nonthoracotomy implantation were prospectively determined.

RESULTS

A nonthoracotomy system was implanted in 72 (71%) of 101 patients. Twenty-nine patients (29%) required thoracotomy. Univariate predictors of successful nonthoracotomy implantation included smaller cardiac size (p < 0.0001), smaller cardiothoracic ratio (p < 0.0002), QRS duration < 120 ms (p = 0.003), female gender (p = 0.006), ventricular fibrillation as the presenting arrhythmia (p = 0.03) and smaller echocardiographic left ventricular size (p = 0.04). Multivariate predictors included smaller cardiac size (p < 0.002) and female gender (p < 0.007). Total actuarial survival over a mean (+/- SD) follow-up interval of 12 +/- 7 months was 91 +/- 0.03% and was not different in the thoracotomy and nonthoracotomy groups.

CONCLUSIONS

A nonthoracotomy cardioverter-defibrillator system can be implanted in a majority of patients. Smaller cardiac size and female gender are associated with a high probability of successful implantation.

Successful implantation of cardioverter-defibrillator systems in patients with elevated defibrillation thresholds

OBJECTIVES

. The purpose of this study was to conduct a retrospective analysis of 16 patients with high initial defibrillation thresholds in whom a three-electrode system was used to lower defibrillation thresholds and permit implantation of a cardioverter-defibrillator system.

BACKGROUND

Patients with high defibrillation thresholds (> 25 J) are uncommon but may be problematic to physicians implanting cardioverter-defibrillator systems. Most conventional systems use two defibrillating electrodes, most commonly two epicardial patches. When defibrillation thresholds remain elevated despite extensive testing of a two-electrode system, a third electrode can be incorporated and tested. However, few published data exist on the use of a three-electrode system in patients with high defibrillation thresholds.

METHODS

After failure to achieve satisfactory defibrillation thresholds < 25 J with a two-patch electrode system, a third electrode was incorporated and tested. In all cases, two electrodes were joined to form a common cathode or anode, while a single electrode was used as the opposite polarity electrode. Various three-electrode configurations were then tested.

RESULTS

In all 16 patients, satisfactory defibrillation thresholds were achieved and a cardioverter-defibrillator was implanted (95% confidence interval [CI] = 0% to 21%). The mean final defibrillation threshold using the revised three-electrode system was 19.5 +/- 3.7 J (p < 0.0001). A mean of 6 +/- 3 electrode configurations/patient were tested before the final configuration was selected. A total of nine different electrode configurations were used in the 16 study patients; the most common of these incorporated left and right ventricular patches as combined cathode and a superior vena cava coil (n = 5) or right atrial patch electrode (n = 3) as single anode.

CONCLUSION

Patients with high initial defibrillation thresholds can generally undergo successful cardioverter-defibrillator implantation with a three-electrode system if enough electrode configurations are tested after a third electrode is incorporated.

Efficacy of a tiered therapy defibrillator system used to treat recurrent ventricular arrhythmias refractory to drugs

OBJECTIVE

To evaluate an implantable tiered therapy defibrillator system that delivered antitachycardia pacing treatment for slower well tolerated ventricular tachycardias and cardioversion or defibrillation for fast tachycardias or ventricular fibrillation.

METHODS

A tiered treatment device (Ventritex Cadence V-100) was implanted in 30 patients with ventricular tachycardia that was refractory to drugs. Efficacy was evaluated by the responses of induced or spontaneous arrhythmias to the treatments delivered.

RESULTS

Antitachycardia pacing successfully terminated 80% of episodes of ventricular tachycardia induced by non-invasive programmed stimulation, but acceleration was brought about by pacing in six patients in 10% of episodes. During a follow up of two to 17 (mean seven) months, 18 patients (60%) had recurrence of ventricular arrhythmias. Antitachycardia pacing terminated ventricular tachycardia in 17 of 18 patients in 87% of episodes. Twelve patients received shocks for ventricular tachycardia or fibrillation. Failure of pacing, with subsequent cardioversion, occurred in nine patients (50%) in one or more episodes. Acceleration of tachycardia by pacing occurred in 10 patients in 5% of episodes. Only two of these patients had experienced acceleration of previously induced arrhythmia. Five patients had spontaneous fast ventricular tachycardia or fibrillation treated by cardioversion or defibrillation. Spurious treatment was delivered in nine patients (30%), during atrial fibrillation in five, sinus tachycardia in two, and because of fracture of the sensing lead system in two patients. The retrieval of stored intracardiac electrograms was of clinical value in assessing spurious treatment.

CONCLUSIONS

Tiered treatment was effective in terminating recurrent ventricular arrhythmias in these selected patients. Most episodes were treated successfully by pacing, and resistant tachycardias, pacing induced acceleration, or haemodynamically compromising arrhythmias were treated by shocks.

Prospective evaluation of day-to-day reproducibility of upright tilt-table testing in unexplained syncope

To evaluate the day-to-day reproducibility of upright tilt-table testing, 109 patients with unexplained syncope prospectively underwent testing on 2 consecutive days using a uniform protocol. Results of testing on 2 separate days were concordant in 69 of 109 patients (63%), and discordant in 40 of 109 patients (37%). Thirty-six of 109 patients (33%) had vasodepressor syncope on 1 or both days of testing. Nineteen of 30 patients (63%) with vasodepressor responses on the first day did not reproduce this response during the second day of testing. An additional 6 patients with an initial negative tilt test had a vasodepressor response on the second day. Only 11 of 36 patients (31%) had reproducible vasodepressor responses on both days of testing. Patients with reproducible vasodepressor responses had a significantly higher mean number of preceding clinical syncopal events than patients with 2 normal tests (p < 0.02) or nonreproducible results (p < 0.04). In addition, these patients had a significantly longer duration of clinical symptoms relative to patients with 2 tests that yielded negative results (p < 0.008) and nonreproducible results (p < 0.01). The elapsed time between the most recent clinical event and the performance of tilt-table testing was not significantly different among the 3 groups, and did not appear to influence the outcome of testing. These data show that vasodepressor responses elicited by upright tilt-table testing show day-to-day variability in many patients, a finding that may limit the interpretation of initial and follow-up test results.

Anti-CD23 monoclonal antibodies: comparisons of epitope specificities and modulating capacities for IgE binding and production

A large battery of anti-CD23 mAb were compared for their epitope specificities and for their abilities to alter both IgE binding to cell-associated CD23 and IgE production in vitro in response to three sets of stimulants. The nine mAb tested can be divided into four families which define four antigenic epitopes (A-D) of CD23. Of these four families, two bind antigenic sites, (A and D) that appear to lie outside the IgE ligand binding site and two bind sites (B and C) that appear to be located within or close to this site, as determined by the abilities of appropriate mAb to alter IgE binding to CD23. The effects that these mAb had on IgE secretion by normal peripheral blood mononuclear cells (PBMNC) varied depending on the stimulant employed to induce IgE production. Interactions with epitope A, which was found to lie outside the ligand binding site and to be made more accessible by binding of mAb to other epitopes, had different effects on IgE production than interactions with the other epitopes. Indeed, mAb binding to this epitope lead to as much as a 10 fold enhancement in IgE biosynthesis induced by IL-4 alone or by IL-4 + hydrocortisone whereas interactions at the other sites resulted in almost complete inhibition of IgE production. In addition, mAb reactive with epitopes B and C had minimal effects on IgE production induced by IL-4 + anti-CD40 mAb whereas interactions at epitope A consistently enhanced IgE production. Finally, no apparent direct correlation was found between the ability of individual anti-CD23 mAb to alter IgE binding to cell-associated CD23 and their ability to modulate IgE production by PBMNC. These studies suggest that IgE binding to cell-associated CD23 does not have a major role in the de novo synthesis of IgE that involves CD23 interactions. In addition, the different effects that binding to epitope A vs B or C have on IgE synthesis suggest that molecular interactions between distinct portions of the CD23 molecule and other cell surface molecules expressed on the same B cell or adjacent communicating cells may lead to divergent cellular effects on IgE production. Finally these studies imply that only epitope A is involved in the generation of an IgE response through the CD40 pathway.

Extended protocol for demonstration of dual AV nodal physiology

The incidence of dual atrioventricular (AV) nodal physiology was evaluated in 22 patients (14 males, 8 females, age 52 +/- 18 years) undergoing electrophysiology studies for evaluation of ventricular tachycardia/nonsustained ventricular tachycardia (n = 11), supraventricular tachycardia (n = 5), and syncope (n = 6). Patients with AV node reentrant tachycardia were excluded. Thirteen patients had normal left ventricular function and nine patients (seven with coronary artery disease, two with dilated cardiomyopathy) had depressed left ventricular function. Single atrial extrastimuli (A2) were introduced after eight-beat drives at paced cycle lengths of 550 msec and 400 or 450 msec beginning at coupling intervals of 650 and 500 or 550 msec, respectively. The coupling interval was decreased at 10-msec intervals until AV node or atrial refractoriness. A second atrial extrastimulus (A3) was then added. A2 was fixed at 50 msec greater than the atrial or AV nodal refractory period. A3 was coupled to A2 at 650 and 500 or 550 msec and decremented as with single extrastimulation. Dual AV nodal physiology was defined by a 50-msec increase in A2H2 or A3H3 with a 10-msec decrement in the coupling interval or a discontinuous H1H2 versus A1A2 or H2H3 versus A2A3 curve. Using a single extrastimulus, 1 of 22 patients demonstrated dual AV nodal physiology. Using double extrastimuli, an additional four patients with dual AV nodal physiology were identified. The occurrence of dual AV nodal physiology determined using double extrastimuli is increased compared to using only a single extrastimulus (P = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Monoclonal IgM, IgG, and IgA human rheumatoid factors produced by synovial tissue-derived, EBV-transformed B cell lines

In an effort to study disease-related autoantibodies in rheumatoid arthritis (RA), rheumatoid factor (RF)-producing B cell lines were developed from the heterogeneous B cell populations infiltrating the synovial tissue of patients with arthritis. Over 125 EBV-transformed B cell cultures were derived from three patients: one with early pre-erosive RA, one with advanced RA, and one with osteoarthritis (OA). IgM, IgG, and IgA RF-producing B cell lines were found in all three series but with several significant differences. In each of the two RA patients, 22% of the Ig-producing cell lines secreted RF compared to 7% in the OA patient. The isotypes of these RF were mostly IgM in the early RA (62%) and the OA patient (60%) as contrasted to predominantly IgA (75%) and, to a lesser extent, IgG (12.5%) in the advanced RA patient. Analyses of the light (L) chain composition of these RF revealed that 82% of the IgM RF used kappa L chains whereas only 31% of the non-IgM RF used kappa chains. Antigen-binding analyses of these RF revealed that all the synovial tissue-derived RF from the advanced RA patient exhibited antigen binding specificities restricted to a narrow range of gamma globulins. In contrast, the synovial RF of the other two patients were either reactive with a broader spectrum of gamma globulins or reactive with a variety of unrelated antigens. In every instance, the gamma globulin-specific RF were of all three major isotypes whereas the polyreactive RF were restricted to the IgM isotype. These data demonstrate that synovial B cells from both RA and OA patients can produce RF and that significant differences can exist among patients in the percentage of RF generated and their H and L chain isotype distribution. The reversal of the kappa:lambda ratio among the IgG and IgA RF and the more restricted antigen-binding specificities of the IgG and IgA vs IgM RF suggest that a non-stochastic, possibly antigen-driven selection process was involved in their generation. The relevance of these differences in RF precursor frequency, H and L chain distribution, and antigen specificity to these two diseases warrants further investigation.

Physiology of "atypical" atrioventricular junctional reentrant tachycardia occurring following radiofrequency catheter modification of the atrioventricular node

The physiology of atypical atrioventricular junctional reentrant tachycardia (AVJRT) occurring following catheter modification of the AV node is poorly defined. Six patients undergoing radiofrequency current catheter modification of the AV node had inducible atypical AVJRT before or after AV nodal modification. Typical AVJRT was differentiated from atypical AVJRT by a ventriculoatrial (VA) time < 60 msec in the His-bundle electrogram recording. Five of six patients had typical AVJRT and two had atypical AVJRT prior to AV nodal modification. Following anterior approach AV nodal modification, previously undetected atypical AVJRT was induced in four patients. Earliest retrograde atrial activation in the posterior septum was documented in all patients with atypical AVJRT prior to modification and in three of four patients with atypical AVJRT following modification. The AH intervals during tachycardia were 320 +/- 52 msec in typical AVJRT, 88 +/- 33 msec in the premodification atypical AVJRTs, and 172 +/- 12 msec in the postmodification atypical AVJRTs (P = 0.0001). The AH/HA ratios were 4.1 +/- 0.9 in typical AVJRT, 0.5 +/- 0.2 in the premodification atypical AVJRTs, and 0.9 +/- 0.2 in the postmodification atypical AVJRTs (P = 0.0001). Two patients with postmodification atypical AVJRT underwent further posterior approach AV node modification that resulted in VA block. One patient with postmodification atypical AVJRT had further anterior approach AV nodal modification that resulted in heart block. The retrograde limb of the atypical AVJRT seen following anterior approach AV nodal modification is a posterior, slow pathway.

Adenosine and the treatment of supraventricular tachycardia

Adenosine has recently become widely available for the treatment of paroxysmal supraventricular tachycardia. In order to evaluate its role in the management of arrhythmias, we have reviewed the literature on the cellular mechanisms, metabolism, potential for adverse effects, and clinical experience of the efficacy and safety of intravenous adenosine. Adenosine produces transient atrioventricular nodal block when injected as an intravenous bolus. This is of therapeutic value in the conversion to sinus rhythm of the majority of paroxysmal supraventricular tachycardias, which involve the atrioventricular node in a re-entrant circuit. The mean success rate was 93% from over 600 reported episodes. Compared with other antiarrhythmic agents, adenosine is remarkable for its rapid metabolism and brevity of action, with a half-life of a few seconds. It commonly produces subjective symptoms, particularly chest discomfort, dyspnea, and flushing, which are of short duration only. No serious adverse effect has been reported. Arrhythmias may recur within minutes in a minority of patients. Comparative studies have shown that adenosine is as effective as verapamil in the treatment of supraventricular tachycardia, and has less potential for adverse effects. Patients with supraventricular tachycardia should initially be treated using vagotonic physical maneuvers. Immediate electrical cardioversion is indicated if the arrhythmia is associated with hemodynamic collapse. Adenosine is the preferred drug in those patients in whom verapamil has failed or may cause adverse effects, such as those with heart failure or wide-complex tachycardia. The safety profile of adenosine suggests that it should be the drug of first choice for the treatment of supraventricular tachycardia, but only limited comparative data to support this view are available at present.

Efficacy and risks of moricizine in inducible sustained ventricular tachycardia

OBJECTIVE

To assess the efficacy and toxicity of moricizine in treating patients with serious ventricular arrhythmias and inducible sustained ventricular tachycardia.

DESIGN

Uncontrolled clinical trial.

SETTING

The intensive care and telemetry units of Northwestern Memorial Hospital, St. Francis Hospital and Medical Center, and Lenox Hill Hospital.

PATIENTS

Twenty-six patients with sustained ventricular arrhythmias or hemodynamically significant nonsustained ventricular tachycardia, most of whom failed therapy with at least one class I antiarrhythmic agent.

INTERVENTION

Patients were treated with moricizine, 400 to 1000 mg/d.

MEASUREMENT

Efficacy was assessed by the results of programmed ventricular stimulation done during moricizine therapy.

MAIN RESULTS

Seven of the 26 patients (27%) developed life-threatening ventricular proarrhythmia during moricizine loading. Three patients had incessant sustained ventricular tachycardia, two had incessant nonsustained ventricular tachycardia, one had new sustained ventricular tachycardia, and one had new cardiac arrest. One of these patients died of intractable ventricular fibrillation. No clinical or electrophysiologic variables clearly identified those at risk for proarrhythmia. Only 3 of 26 patients (12%) became noninducible on moricizine.

CONCLUSION

Moricizine has a low rate of efficacy and carries a considerable risk for life-threatening proarrhythmia in patients with serious ventricular arrhythmias and inducible ventricular tachycardia who have failed therapy with other class I antiarrhythmic agents.

Electrophysiologic response to moricizine in patients with sustained ventricular arrhythmias

OBJECTIVE

To assess the short-term efficacy and safety of moricizine in patients receiving electrophysiologically guided therapy for sustained ventricular arrhythmias refractory to treatment with class IA antiarrhythmic agents.

DESIGN

Uncontrolled clinical trial.

SETTING

Referral-based teaching medical center.

PATIENTS

Twenty-one patients (18 of whom had coronary artery disease) with a mean left ventricular ejection fraction of 32% +/- 11% who presented with sustained ventricular tachycardia (13 patients), syncope (4 patients), or cardiac arrest (4 patients).

INTERVENTIONS

Moricizine, 743 +/- 85 mg daily.

MEASUREMENTS

Electrophysiologic testing in the drug-free state and after administration of moricizine unless sustained arrhythmias occurred.

MAIN RESULTS

Sustained ventricular tachycardia was inducible in the absence of antiarrhythmic drugs in 20 patients and was not suppressed by moricizine in any patient. Four patients had six episodes of spontaneous ventricular tachycardia while receiving moricizine. A probable proarrhythmic response occurred in four patients.

CONCLUSION

In patients with compromised left ventricular function caused by coronary artery disease in whom class IA antiarrhythmics were ineffective, moricizine was ineffective in suppressing sustained ventricular arrhythmias and resulted in proarrhythmic effects in some patients.

Down-regulation of scatter factor in MRC 5 fibroblasts by epithelial-derived cells. A model for scatter factor modulation

Scatter factor/hepatocyte growth factor (SF/HGF) is a multifunctional cytokine produced by embryonic fibroblasts and other mesenchymal cells that affects the growth and/or the movement of certain epithelia. Here we report that expression of scatter factor activity by MRC 5 cells, a strain of normal human embryonic lung fibroblasts, is greatly reduced as a result of co-culture of these cells with SVK14, an SV40-transformed human keratinocyte cell line. Using a cDNA probe to the beta chain of human HGF, we have found that the fall in SF activity in MRC 5/SVK14 co-cultures is accompanied by the loss of SF/HGF transcripts. As the inhibition of SF activity coincides with the disappearance of SF/HGF transcript, we conclude that inhibition of the SF activity expressed by MRC 5 cells by co-culture with SVK14 involves transcriptional regulation.

Current treatment of patients surviving out-of-hospital cardiac arrest

Most out-of-hospital cardiac arrests result from the sudden onset of a sustained ventricular arrhythmia in the absence of a new myocardial infarction. Individuals who survive cardiac arrest are at high risk for recurrent arrhythmias and sudden unexpected death. To prevent recurrent cardiac arrest, effective treatment must be provided during hospitalization after the initial episode. Caring for the survivor of cardiac arrest requires a detailed clinical investigation to define the underlying cardiac anatomy and left ventricular function and to elucidate the mechanism and characteristics of the patient's arrhythmia. Appropriate antiarrhythmic therapy, such as drugs or a nonpharmacological intervention (eg, implantable cardioverter-defibrillator), is then selected based on these considerations. In addition, ischemia is treated aggressively with beta-adrenergic blocking agents and, when appropriate, with surgical coronary artery revascularization.

Survey of the dog population of Zimbabwe and its level of rabies vaccination

A random sample survey using personal interviews was conducted in Zimbabwe in 1986 to determine the size and structure of the national dog population and its level of rabies vaccination. There was an average of 0.91 dogs per household in Zimbabwe giving an extrapolated total population of 1,308,577 dogs. There was a dog to people ratio of 1:6.5 and an average of 3.4 dogs per square kilometre. The ratio of adult male to female dogs was 0.56:0.44, with 20 per cent of the dog population being less than three months old. In the period 1950 to 1986 there was a 4.7 per cent per annum growth rate of the dog population. In one of the provinces, Manicaland, dogs were found to have an average age of 2.3 years and a life expectancy at birth of 4.6 years. An estimated 40 per cent of the dog population three months old and above had been vaccinated against rabies in 1985/1986. With the rabies incidence in Zimbabwe still unacceptably high this level of vaccination is clearly inadequate and measures designed to increase it are discussed.

Do social admissions exist?: a clinical study of emergency admissions into residential care in Birmingham

A medical and social assessment was performed on 132 emergency admissions into Local Authority residential care. The main reasons for admission included withdrawal of an informal carer, disturbed behaviour and a physical disaster. Medical conditions were commonly found, and chronic brain failure was present in over half of all admissions. The incidence of severely disturbed behaviour was found in a small proportion of clients, with psychiatric disability predominating in just under half of those assessed. Both medical and social services were slow to respond to the need for appropriate placement, with fifty per cent of admissions occupying the emergency bed after four weeks. A medical assessment at the time of admission would have led to a more appropriate course of action, although in many cases this would have meant admission to hospital.

Comparison of a protein-stabilized Rotazyme II test, with standard Rotazyme II, and electron microscopy for detection of rotavirus

We compared the performance of Rotazyme II with protein-stabilized diluent to standard Rotazyme II and to direct electron microscopy, for the detection of rotavirus. Sensitivity and specificity were: standard Rotazyme II, 79 and 100%, respectively; Rotazyme II with protein stabilizers, both 100%, and electron microscopy, 75 and 100%, respectively. Commercial availability of this product should improve rotavirus detection for laboratories utilizing Rotazyme II methodology.

Small cell carcinoma of urinary bladder

A fifty-seven-year-old woman with urinary bladder carcinoma with extensive areas resembling oat cell carcinoma of the lung in whom distant metastases developed, died seven months after diagnosis. Argyrophil cells could not be demonstrated, but electron microscopy demonstrated dense-core, membrane-bound intracytoplasmic granules. We reviewed 12 cases of epithelial neoplasms of the bladder from the literature in which there was ultrastructural evidence of neuroendocrine differentiation. Cases with malignant histologic features, like their pulmonary counterparts, have the potential for widespread dissemination and rapid growth. We support the previous suggestion that these neoplasms may be of considerable incidence and their recognition is important to determine prognosis and selection of therapy.

Idiopathic ventricular tachycardia. A review

Idiopathic or unexplained VT occurs in a small but important subset of patients without clinically evident heart disease. The majority of these patients appear to have a structurally normal heart. The cause of the arrhythmias in these individuals is unclear and may never be recognized. Other patients with this condition may have minor abnormalities not sufficient to impair overall cardiac function. The significance of these abnormalities to the genesis of the arrhythmia is uncertain. Whether patients with minor abnormalities are more likely to harbor covert heart disease such as myocarditis or a focal defect is not known, nor is it resolved whether such patients warrant a more aggressive search for a structural cause. The question that remains in any patient not subjected to surgical or pathological exploration is whether undetermined heart disease is responsible for the arrhythmia. Continued correlation between functional (electrophysiological) and structural (pathological) data will provide meaningful information concerning the pathophysiology (substrate) of these arrhythmias. Because of the preservation of normal cardiac function, these arrhythmias are generally well-tolerated. Although the condition is usually associated with a favorable prognosis, the occasional deaths reported in patients with apparently idiopathic ventricular arrhythmias may not permit calling this condition benign. It would be important to know the extent to which unrecognized abnormalities play a role in the genesis of these tachycardias, and whether such patients are more predisposed to fatal arrhythmias or have a different natural history. If cases involving undetermined or covert heart disease were excluded from consideration, then a relatively homogeneous disease-free group may be identified with a truly benign condition and a uniformly favorable prognosis. In these cases, a primary electrical abnormality may prove to be the basis for the arrhythmia. These issues remain to be elucidated in future studies.

A baiting system suitable for the delivery of oral rabies vaccine to dog populations in Zimbabwe

A baiting system suitable for the delivery of oral rabies vaccine to dog populations in developing countries was studied in Zimbabwe. In a field trial, 369 sponge baits containing a placebo liquid, rhodamine B as a biomarker and a pungent attractant were distributed over an area of 60 sq km in a communal land in Manicaland with a dog population of over 500. Twenty-four hours later 21 per cent of the baits were recovered and 79 per cent of these had been significantly bitten or chewed. Twenty-five per cent of the dogs examined showed evidence of superficial staining by rhodamine B indicating that they had chewed baits or ingested their contents. It was concluded that the system would deliver an oral vaccine to dog populations more efficiently than had been the case in comparable studies in wildlife populations, but that the number of baits per unit area should in future studies be increased.

Association between immediate termination of supraventricular tachycardia by carotid sinus pressure and carotid sinus hypersensitivity

An association between rapid reversion of supraventricular tachycardia by carotid sinus stimulation and carotid sinus reflex hypersensitivity during sinus rhythm is described in a 55-year-old patient. The findings indicate that a high level of vagal tone facilitates vagal maneuvers in terminating some supraventricular tachyarrhythmias. The briskness of the response during tachycardia may also be a marker for underlying carotid sinus hypersensitivity.

Torsade de pointes ventricular tachycardia in a hypothyroid patient treated with propafenone

A 31-year-old female had recurring palpitations and black-outs for 13 years. Hyperthyroidism was diagnosed and electrocardiogram suggested ventricular preexcitation. Despite being treated for hyperthyroidism (which rendered the patient hypothyroid) and receiving propranolol for the arrhythmia, the palpitations persisted. Electrophysiologic testing identified the patient's arrhythmia, and demonstrated that it improved with intravenous propafenone, a new type 1C antiarrhythmic medication. After two days of oral propafenone, this initially good response was followed by episodes of Torsade de pointes ventricular tachycardia with repeated cardiac arrest. Lidocaine and isoproterenol failed to control the rhythm, and the patient was stabilized by electrical cardioversions, atrial pacing and withdrawing the propafenone. Propafenone has been used to treat Torsade de pointes, but we show that it may also cause Torsade de pointes.

Bony ankylosis in rheumatoid arthritis. Associations with longer duration and greater severity of disease

Hand and wrist radiographs of 203 patients with rheumatoid arthritis were examined for bony ankylosis. Forty-eight patients (23.6%) showed ankylosis, including 34 with more than one joint fused. The distribution of ankylosed joints was 32.4% midcarpal, 29.5% common carpometacarpal, 15.8% radiocarpal, 15.8% proximal interphalangeal, and 6.5% metacarpophalangeal. Patients with ankylosis had significantly higher radiographic erosion, joint space narrowing, and malalignment scores than those without ankylosis (all P less than .001). Patients with ankylosis had significantly longer duration of disease (P less than .001) and physical examinations showed more limited motion and deformity (both P less than .001). More patients with ankylosis had subcutaneous nodules (P less than .05). Functional testing with grip strength and the button test revealed poorer performance in patients with ankylosis (both P less than .001). Questionnaires revealed patients with ankylosis had more difficulty with activities of daily living (P less than .001) and had more limited activity (P less than .01); physicians estimated more limited functional capacity (P less than .001). Thus, radiographic bony ankylosis was a relatively common feature of rheumatoid arthritis, and a marker of patients whose disease was clinically, radiographically, and functionally more severe.