Acute procedural characteristics, efficacy, and safety of a novel cryoballoon for the treatment of paroxysmal atrial fibrillation: Results from the POLAR-ICE study

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Boston Scientific

Background/Introduction

Pulmonary vein isolation (PVI) using a cryoballoon is well-established for the treatment of paroxysmal atrial fibrillation (PAF). Initial experience with a novel cryoballoon (CB) with a stable low balloon pressure (POLARx, Boston Scientific) has demonstrated acute procedural safety and efficacy in de novo PVI procedures in patients with paroxysmal AF. However, to date, there is limited multicenter data on real world acute outcomes and procedural characteristics with this novel cryoballoon.

Purpose

The purpose of POLAR ICE was to provide real-world data on the acute and chronic outcomes of cryoballoon ablation with POLARx for the treatment of PAF. Here we report on the initial acute outcomes up to 3 months including procedural efficacy, safety, and biophysical parameters.

Methods

POLAR ICE, a prospective, non-randomized, multicenter (international) registry (NCT04250714), enrolled 400 patients across 19 centers, between Aug 2020 and May 2021. This study included any patients indicated for treatment of PAF with the POLARx cryoablation system. The study protocol did not mandate any specific cryodosing regimen, this was left to the operator. Procedural characteristics, such as time to isolation (TTI), cryoablations per pulmonary vein, balloon nadir temperature, and occlusion grade were recorded. PVI was confirmed with entrance block testing.

Results

Complete PVI was achieved in 96.1% of PVs (1437/1496). Procedure and fluoroscopy times were 69.0±25.2 min and 15.8±10.0 min, respectively. Left atrial dwell time was 47.3±18.8 min. The cryoablation characteristics by vein are shown in the Table 1. An average of 4.9±1.8 ablations were performed per patient (1.3±0.7 per vein). Grade 3 or 4 occlusion was achieved in 98.1% of PVs reported. Electrical isolation was achieved with an average TTI of 50±33.8s and in 81.4% of PVs isolation required only a single cryoablation. Nadir temperatures across all pulmonary veins averaged -56.3± 6.5C. Time to -40C was 32.9±11s and Time to Thaw (0C) was 19.5±6.7s across all veins. PVI was performed on atypical anatomies (12 LCPV, 7 RMPV, & 3 RCPV) in 19 pts. Serious adverse events included phrenic nerve palsy (0.5%), tamponade (0.5%), AV block (0.3%), stroke (0.3%), and transient ischemic attack (0.3%).

Conclusions

Real world usage data on the novel CB suggests that this device is safe and effective, with a PV isolation success rate of 96.2% and 81.4% of PVs isolated with a single cryoablation. These data are in keeping with reports on other cryoballon systems and have markedly shorter procedure times than have been previously reported on this cryoballon.

Identifying predictive risk factors for permanent pacemaker implantation up to 30 days post-TAVI

Background

Conduction system abnormalities, including AV block, are amongst the most common complications of transcatheter aortic valve implantation (TAVI). Post-TAVI high degree AV block necessitates permanent pacemaker (PPM) implantation.

Purpose

To assess the ability of standardly available pre-, intra- and post-TAVI factors to predict PPM implantation within 30-days post procedure.

Methods

Demographic and clinical (pre-, intra-, and post-procedural) data including ECG parameters were collected from all patients who underwent TAVI at our centre from August 2017 to November 2020. Patients with pre-existing PPM were excluded from the study. Predictive factors were selected through univariate analysis, and selected characteristics were incorporated into a multivariate binomial logistic regression model, in order to create a 30-day PPM risk-prediction model. The Akaike information criterion (AIC) and area under receiver operating curve (AUC/C-statistic) were used to assess discriminative performance.

Results

In total, data from a total of 446 patients were analysed. Of these, 40 (8.97%) received PPM implantation within 30 days of the procedure. The mean age of the patients was 81.5 (±7.3 SD) years; 99 (22.2%) had pre-existing first degree AV block, 55 (12.3%) had pre-existing left bundle branch block (LBBB) and 50 (11.2%) had pre-existing right bundle branch block (RBBB). Intra-procedurally 40 (9.0%) developed LBBB, 21 (4.7%) developed 3rd degree AV block, and 95 (21.3%) patients required temporary pacing wire (TPW) pacing. Post-procedurally, 138 (30.9%) exhibited AV block, 107 (24.0%) LBBB and 50 (11.2%) RBBB.

The following factors met significance at multivariate logistic regression analysis: pre-TAVI RBBB (OR 6.62 [95% CI, 1.37–36.51]), intra-TAVI 3rd degree AV block (OR 12.80 [95% CI, 3.44–53.34]), intra-TAVI LBBB (OR 4.02 [95% CI, 1.28–12.53]), use of TPW pacing (OR 8.58 [95% CI, 3.19–25.12]) and post-TAVI LBBB (OR 7.84 [95% CI, 2.75–24.46]) (Table).

Finally, variables were incorporated into a multivariate logistic regression model with the outcome variable of 30-day PPM implantation (Figure 1a). A model incorporating five factors (pre-TAVI RBBB, intra-TAVI 3rd degree AV block, intra-TAVI LBBB, use of TPW pacing and post-TAVI LBBB) demonstrated excellent discriminative ability (accuracy 0.925 and an AUC of 0.952) at predicting PPM implantation (Figure 1b).

Conclusions

Following variable selection, the best performing model incorporated five factors including pre-TAVI RBBB, intra-TAVI AV block (3rd degree), intra-TAVI LBBB, use of TPW pacing and post-TAVI LBBB. We aim to validate this model using an external cohort.

Funding Acknowledgement

Type of funding sources: None. Table 1Figure 1

Prevalence and clinical impact of atrioventricular conduction disease in patients with idiopathic pulmonary arterial hypertension

Background

Although bradycardia-related sudden death is common in patients with idiopathic pulmonary arterial hypertension (IPAH), the prevalence and prognostic significance of atrioventricular (AV) conduction disease in this patient group is not well-established.

Objectives

– Determine the prevalence of AV conduction disorders in patients with IPAH

– Investigate the relationship between AV block and functional outcomes and mortality.

Method

12-lead electrocardiograms (ECGs) of patients with IPAH were analysed. Patients were categorised according to the presence or absence of AV block. Demographic, pulmonary haemodynamic, cardiac structural characteristics and expression of genes associated with cardiac conduction were compared and functional and mortality outcomes analysed between groups.

Student's t-tests and χ2 tests were used to compare data. Survival was estimated using Kaplan-Meier analyses. Initial exploratory covariates were included in a univariate analysis and those terms with P-value of <0.1 were then used to generate a Cox proportional-hazards multivariate model.

Results

135 IPAH patients (mean age 55±16 years, 28.1% male) were eligible for analysis. Median follow up was 9 years (interquartile range 4–14 years).

AV block was seen in 34.8% of patients with IPAH compared to 10.8% of matched comparators (p<0.001), drawn from patients attending hospital for non-PAH related reasons.

IPAH patients with conduction disease were more likely to be older (59±16 vs 53±17 years, p=0.038). AV block was associated with more severe right ventricular (RV) basal dilatation (5.1±1.0 vs 4.3±0.7cm, p=0.013) and worse RV function (fractional area change 26±9% vs 31±9%, p=0.14). Pulmonary haemodynamics, right atrial size and resting and exertional oxygen saturations were not significantly different. Expression of HCN1, HCN2, SCN1B, SCN5A, CAV1, and KCN2 genes in peripheral blood from a subcohort was similar between those with and without AV block.

Lower 6 minute walk distances (344±153 vs 408±140m, p=0.035) and worse CAMPHOR scores across all 3 domains were seen in those with AV block (figure 1), and mortality was significantly higher (36.2 vs 13.6%, p=0.002) (figure 2). On multivariate analysis the presence of bundle branch block (BBB) was independently associated with a 2.1-fold increased risk of death (95% CI 1.89–4.85, p=0.045).

Conclusions

AV conduction disorders are more prevalent in IPAH than the general population, and are associated with worse prognosis and functional status. Prospective study is required to validate this finding.

In our cohort AV block could not be explained by hypoxia, differences in pulmonary haemodynamics nor, in a small subgroup, by differential expression of specific transmembrane ion channels implicated in cardiac conduction. More detailed investigation into causal mechanisms of AV block in IPAH could establish whether improved prognosis could be achieved by treatment of AV block.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

The role of marshall bundle epicardial connections in atrial tachycardias after atrial fibrillation ablation

Funding Acknowledgements

Type of funding sources: None.

Background

Atrial tachycardias (ATs) are often seen in the context of AF ablation.

Objectives

We evaluated the role of the Marshall bundle (MB) network in left atrial (LA) ATs using high-density high-spatial resolution 3D mapping.

Methods

199 post-AF ablation LA tachycardias were mapped in 140 consecutive patients (112 (80%) males, mean age: 61.8 years); 133 (66.8%) were macro-reentrant and 66 (33.2%) were scar-related re-entry. MB-dependent perimitral AT (PMAT) was diagnosed where the difference between the post pacing interval and the tachycardia cycle length (PPI-TCL) was <20ms in parts of the expected MB-dependent perimitral circuit (within the VOM, the ridge between the left pulmonary veins and LA appendage (LAA), the anterior LA and between 6- and 11-o’clock of the mitral annulus) and the PPI-TCL was >20ms in areas bypassed by the VOM (the distal coronary sinus (CS), the posterior LA and the mitral isthmus). MB-related re-entry was diagnosed by PPI-TCL <20ms at the left lateral ridge, posterior base of LAA, inferolateral LA or VOM ostium; and PPI-TCL >20ms in the septal annulus. Typically, in MB-dependent localized re-entry, the earliest activation was found along the MB-LA endocardial connection or MB-CS epicardial connection. 

Results

The MB network was found to participate in 60 (30.2%) re-entrant ATs, 31 PMATs and 29 localized re-entries. High-frequency multiphasic fragmented electrograms with long duration were often recorded endocardially or epicardially at the MB-LA or MB-CS connections. The amplitude and duration of these signals were 0.5 ± 0.79 mV and 65 ± 40 ms for MB-PMATs and 0.26 ± 0.28mV and 122 ± 67 ms for MB-localized re-entries. Unipolar EGMs at the site of endocardial-epicardial breakthrough had a rS pattern in all MB-related ATs. Of 60 MB-related ATs, 49 (81.6%) terminated with RF ablation, 44 (73.3%) at the MB-LA junction and 5 (8.3%) at the MB-CS junction, while 9 (15%) terminated after 2.5-5 cc of alcohol infusion inside the vein of Marshall (VOM). Of the 31 MB-related macroreentrant ATs, 17 (54.8%) terminated at the MB-LA junction, 5 (16.1%) at the MB-CS junction and 7 (22.6%) with alcohol infusion inside the VOM. Two macroreentries (6.5%) using the MB did not terminate with RF energy either endocardially at the MB-LA junction or epicardially at the MB-CS junction, and we were unable to identify or cannulate the VOM for ethanol infusion. Of the 29 localized re-entrant ATs using the MB, 27 (93.1%) terminated at the MB-LA junction, none terminated at the MB-CS junction and 2 (6.9%) terminated after alcohol infusion. After a mean follow up of 12 months, only 4 patients (6.7%) had AT recurrence.

Conclusions

MB re-entrant ATs accounted for up to 29% of the left ATs after AF ablation. Ablation of the MB-LA or CS-MB connections or alcohol infusion inside the VOM is required to treat these arrhythmias. Abstract Figure.

Impact of PhORCAS references on overall application score for postgraduate year 1 pharmacy residency candidates

Purpose

The disparity between the number of applicants for postgraduate year 1 (PGY1) pharmacy residency positions and the number of available residency positions increases the need to optimize how applicants are evaluated. The purpose of the study described here was to evaluate the correlation of ratings of residency candidate characteristics by academic and professional references listed on residency applications with overall application score, applicant ranking, and the likelihood of candidates receiving an invitation to interview.

Methods

A multicenter, retrospective study was conducted to evaluate the correlation of reference writers’ ratings of 13 candidate characteristics and their overall recommendations with program-determined outcomes (eg, final application score, applicant ranking, and invitation to interview) through analysis of PGY1 applications submitted through the Pharmacy Online Residency Centralized Application System (PhORCAS) from 2015 through 2018. Keywords and themes within the open-ended section of letters of reference were also analyzed for correlation with overall application score.

Results

A total of 5,923 references listed on 1,867 applications to 4 PGY1 pharmacy residency programs processed by PhORCAS were included in the analysis. For the majority of applicant characteristic ratings (ie, 74% of 56,872 ratings overall), reference writers rated candidates as exceeding expectations, and applicants were “highly recommended” by these evaluators in 91% of cases. References’ average characteristic ratings and overall recommendations were poorly correlated with final application score (R2 = 0.12 [P < 0.0001] and R2 = 0.08 [P < 0.0001], respectively), final ranking (R2 = 0.02 [P < 0.0001] and R2 = 0.03 [P < 0.0001], respectively), and invitation to interview (R2 = 0.07 [P < 0.0001] and R2 = 0.04 [P < 0.0001], respectively). For the themes evaluated, references’ use of teaching words best correlated with normalized final application score, although the correlation was poor (R2 = 0.007, P = 0.0001).

Conclusion

Reference writers’ ratings of PGY1 residency candidate characteristics in PhORCAS are poorly correlated with application score, applicant ranking, and invitation to interview. The results of this study suggest that the existing PhORCAS standardized form for submitting references is of limited utility in its current state.

P1000Aetiology and efficacy of atrial fibrillation ablation in young adults

Introduction

Little is known regarding the aetiology or outcome of atrial fibrillation (AF) occurring in young adults. This retrospective analysis was performed to explore the demographics and efficacy of AF ablation in this population.

Methods

Patients were included who had undergone ≥1 AF ablation under the age of 40 between 2006-2018. Recurrence was defined as return of either documented AF or previous symptoms for >30s following a 3-month blanking period. Initial exploratory co-variates were included in a univariate analysis and those terms with P-value of <0.1 were then used to generate a Cox proportional-hazards multivariate model.

Results

124 patients (33.6 ± 4.7 yrs, 77% men), initially presenting with paroxysmal AF (pAF; n = 97) or persistent AF (n = 27), underwent 175 AF ablation procedures. 22.6% (n = 28) also had atrial flutter. Time from symptom onset to first ablation was 50.7 ± 46.2 months. Relevant cardiovascular-related demographics were analysed: hypertension in 8.9% (n = 11); diabetes in 1.6% (n = 2); positive family history of AF in 12.9% (n = 16); and family history of sudden cardiac death in 2.4% (n = 3). Mean CHA2DS2-VASc score was 0.35. Of those patients with documented echocardiogram imaging (n = 91), 26.4% (n = 24) had LA dilatation and 6.6% (n = 6) had LV dysfunction. Patients with LA dilatation underwent more ablations (2.3 ± 0.3) compared to controls (1.5 ± 0.1; p < 0.001).

Ablation strategy was pulmonary vein isolation (PVI) only in 67.2% (n = 119), with additional ablation in the remaining: roof line in 18.9% (n = 33); cavotricuspid isthmus line in 13.1% (n = 23); mitral isthmus line in 2.3% (n = 4); superior vena cava isolation in 2.3% (n = 4); complex fractionated atrial electrograms in 14.9% (n = 26). Mean procedure time was 155 ± 41 min, mean ablation time was 1657 ± 991 s and mean fluoroscopy time was 32.6 ± 23.4 min. General anaesthesia was used in 43.4% (n = 76). Complications included femoral haematoma (n = 2), tamponade (n = 1) and pulmonary vein stenosis (n = 2).

90 days of follow-up was available for 137 procedures performed for pAF (n = 105) and persistent AF (n = 32). For pAF, overall recurrence was 61.9% for first ablations and 62.9% overall. Recurrence was 56.3% for persistent AF.

Factors significantly associated with increased AF recurrence in univariate analysis were

male gender (hazard ratio (HR) 2.3, 95% confidence interval (CI): 1.2-4.4, p = 0.011), hypertension (HR 0.5, CI: 0.2-1.1, p = 0.067), family history of sudden cardiac death (HR 6.8, CI: 1.6-29.0 , p = 0.010) and enlarged LA size (HR 2.2, CI: 1.3-3.6, p = 0.003). In multivariate analysis, the only significant predictor of poor outcome was enlarged LA size (HR 2.0, 95% CI: 1.2-3.5, p = 0.011).

Conclusions

Young patients with AF may have structurally abnormal hearts, and therefore do not only present with lone AF. LA size may be used as a predictor for success. Surveillance imaging may be useful to detect future structural change, which will be the subject of future prospective studies.

Abstract Figure. AF ablation recurrence in young adults

P1381Improved outcome in ablation of ventricular tachycardia in patients with structural heart disease under general anaesthetic

Background

Catheter ablation is an important adjunct to device implantation for secondary prevention of ventricular tachycardia (VT). However, several factors may influence the success of ablations in terms of long-term freedom from VT recurrence. A thus far little examined factor is the use of general anaesthetic (GA) versus conscious sedation during the procedure, which has been shown to improve outcomes in persistent atrial fibrillation (AF) ablation.

Methods

Patients with structural heart disease VT undergoing ablations from January 2015 to March 2019 were retrospectively followed up at a single centre. End points were recurrent VT or device therapy (shock or anti-tachycardia pacing) at one year. Hazard ratios (HR) were generated using a multivariate Cox-regression proportional hazards model including variables of age at ablation, sex, amiodarone use at time of ablation, scar age, left ventricular ejection fraction, use of GA, and diagnosis of: diabetes mellitus (DM), hypertension (HTN), renal impairment or AF.

Results

79 patients (74 male, mean age 68.2+/- 10.3 years) were included. A substrate-based strategy of late potential ablation was employed. 69 had ischaemic and 10 had non-ischaemic cardiomyopathy. Mean scar age was 13.8 +/- 9.8 years; EF was 40-50% in 27 patients, 30-40% in 26 and < 30% in 26. 37 patients had implantable cardioverter defibrillators and 30 had cardiac resynchronisation therapy (CRT) defibrillator devices, 1 had a CRT- pacemaker device and 4 had dual chamber pacemakers. Comorbidities were: DM (16), HTN (31), renal impairment (13), AF (31). 62 patients (79.5%) were on amiodarone at the time of ablation. Mean procedure duration was 234.8 +/- 44.5 min and mean radiofrequency energy application time was 2247 +/- 862 s. 61 were first procedures and 18 were repeat procedures. One patient suffered a complication of groin haematoma. 62 patients (78.5%) underwent VT ablation under GA and 17 (21.5%) under sedation of midazolam and fentanyl. Patient characteristics did not differ between groups. Significant factors which increased freedom from VT recurrence or device therapy were HTN (88.9% vs 59.4%, HR 0.72, 95% confidence interval (CI): 0.007-0.75, p= 0.028), amiodarone treatment (50.0% vs 76.3%, HR 0.036, 95% CI: 0.003-0.404, p = 0.036) and ablation under GA rather than sedation (50.0% vs 75.0%, HR 0.055, 95% CI: 0.006-0.495, p = 0.01) (Fig 1).

Conclusions

In patients with structural heart disease undergoing VT ablation, outcomes are improved with the use of GA over conscious sedation.

Abstract Figure 1

P6586Brugada syndrome risk stratification - Evaluation of clinical and ECG risk markers in a multicenter international primary prevention cohort

Background

Risk stratification for sudden cardiac death (SCD) in Brugada syndrome (BrS) is a significant challenge.

Purpose

To evaluate the importance of clinical and ECG factors in the likelihood of developing significant ventricular arrhythmias (VAs)/SCD in BrS patients.

Methods

VA occurrence during follow-up were assessed and the role of 16 proposed clinical or ECG risk markers evaluated in a multicenter international study of BrS patients and no history of cardiac arrest. Markers with predictive power were identified and incorporated into a risk score model.

Results

Across 15 international centers, 1084 patients were included. During a follow-up of 5.3 years (IQR 2.7–9.0 years)- 110 patients had VA occurrence (10.1%) with an annual event rate of 1.7% (95% CI 1.4–2.0). Of the 16 proposed risk factors, diagnosis by family screening of sudden cardiac death (HR 4.65; p<0.001), probable arrhythmia related syncope (HR 3.88, p<0.001), type 1 spontaneous ECG (HR 3.56; p<0.001), Early Repolarisation (HR 3.15; p<0.001) and type 1 Brugada pattern in peripheral leads (HR 2.42; p<0.001) were associated with a higher VA occurrence risk during follow-up. These 5 variables were incorporated into a risk score model whereby each variable was allocated a point score based on the variable's predictive strength. The total points obtained from the model for a patient could then be translated into the predicted VA occurrence risk during follow-up (Figure 1). The model showed a sensitivity of 63.5% (95% CI 50.0–76.9) and specificity of 84.2% (95% CI 81.1–87.1) in predicting VA occurrence at 5-years follow-up. The model showed a greater discriminative power compared to an existing model (AUC 0.83 vs. 0.71; p<0.001).

Figure 1

Conclusions

This multicenter study with longest reported follow-up to date identified 5 risk markers for VA occurrence. Utilizing these markers in a risk score model can aid BrS risk stratification to enable individualized risk prediction and ICD prescription.

1026. Trends in Infective Endocarditis During the Substance Use Disorder Epidemic at an Academic Medical Center

Background

In many areas of the United States, substance use disorders (SUD) have increased dramatically over the past decade. Overdose deaths have increased as well, and Kentucky ranks among the nation’s leaders in deaths per 100,000 population. Infective endocarditis (IE) is a well-known complication of intravenous drug use, contributing to significant morbidity and mortality, but few studies have evaluated the effect of the current SUD epidemic on rates and demographics of IE. We sought to examine the trends in IE and IE with SUD at our institution.

Methods

We collected data from patients admitted to a large academic medical center in Kentucky between January 1, 2013 and December 31, 2016. Patients were classified according to the International Classification of Diseases, Tenth Revision. Patients were considered to have IE if they received codes I33 or I38. Patients were considered to have an SUD if they received codes F11.10, F15.10, F14.10, F19.10, or Z86.59. Data were collected through the TriNetX database (TriNetX, Cambridge, MA).

Results

There were 2,100 cases of IE during the study period. The mean (SD) age was 53 years (21). Of those, 440 also had an SUD. The mean (SD) age of these patients was 41 years (11). Patients in both the IE and IE/SUD categories were primarily male (54% and 55%) and white (94% and 94%). The number of cases of IE increased from 190 in 2013 to 430 in 2016 (R² = 0.9877). The number of IE cases diagnosed as having an SUD increased from 30 (16% of all IE cases) in 2013 to 130 (30% of all IE cases) in 2016 (R² = 0.7352 for the trend). This increase in cases corresponds to a 333% increase in the number of cases of IE with SUD.

Conclusion

Between 2014 and 2016, opioid overdose deaths in Kentucky rose from 24.7 to 33.5 per 100,000 population, a 35.6% increase. During a similar timeframe, the number of IE cases associated with SUD at our institution rose 333%. While it is possible that increased coding of substance use disorders factored into this dramatic increase, it appears that the number of IE cases associated with SUD is rising at a disproportionately rapid rate.

Disclosures

All authors: No reported disclosures.

Assessment of a conduction-repolarisation metric to predict Arrhythmogenesis in right ventricular disorders

BACKGROUND

The re-entry vulnerability index (RVI) is a recently proposed activation-repolarization metric designed to quantify tissue susceptibility to re-entry. This study aimed to test feasibility of an RVI-based algorithm to predict the earliest endocardial activation site of ventricular tachycardia (VT) during electrophysiological studies and occurrence of haemodynamically significant ventricular arrhythmias in follow-up.

METHODS

Patients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) (n = 11), Brugada Syndrome (BrS) (n = 13) and focal RV outflow tract VT (n = 9) underwent programmed stimulation with unipolar electrograms recorded from a non-contact array in the RV.

RESULTS

Lowest values of RVI co-localised with VT earliest activation site in ARVC/BrS but not in focal VT. The distance between region of lowest RVI and site of VT earliest site (Dmin) was lower in ARVC/BrS than in focal VT (6.8 ± 6.7 mm vs 26.9 ± 13.3 mm, p = 0.005). ARVC/BrS patients with inducible VT had lower Global-RVI (RVIG) than those who were non-inducible (-54.9 ± 13.0 ms vs -35.9 ± 8.6 ms, p = 0.005) or those with focal VT (-30.6 ± 11.5 ms, p = 0.001). Patients were followed up for 112 ± 19 months. Those with clinical VT events had lower Global-RVI than both ARVC and BrS patients without VT (-54.5 ± 13.5 ms vs -36.2 ± 8.8 ms, p = 0.007) and focal VT patients (-30.6 ± 11.5 ms, p = 0.002).

CONCLUSIONS

RVI reliably identifies the earliest RV endocardial activation site of VT in BrS and ARVC but not focal ventricular arrhythmias and predicts the incidence of haemodynamically significant arrhythmias. Therefore, RVI may be of value in predicting VT exit sites and hence targeting of re-entrant arrhythmias.

Comparison of ß-lactam plus aminoglycoside versus ß-lactam plus fluoroquinolone empirical therapy in serious nosocomial infections due to Gram-negative bacilli

We sought to compare clinical cure on day 7 and a 28-day all-cause mortality in patients who received an anti-pseudomonal ß-lactam with a fluoroquinolone or an aminoglycoside for treatment of nosocomial bacteremia or pneumonia due to Gram-negative bacilli while in the ICU. This retrospective cohort study was conducted in critically ill patients at an academic medical centre from January 2005 to August 2011. A total of 129 patients (83 receiving aminoglycoside and 46 receiving fluoroquinolone combinations) were included. Seven-day clinical cure rates were 74% and 72% for fluoroquinolone and aminoglycoside groups, respectively (p = 0.84). There was no significant difference in the odds of clinical cure with a fluoroquinolone as compared to an aminoglycoside combination (adjusted odds ratio 2.4, 95% confidence interval [CI] 0.7-9.0). There was no significant difference in 28-day mortality in patients who received a fluoroquinolone or an aminoglycoside combination (22% vs. 18%, adjusted hazard ratio 0.82, 95% CI 0.29-2.28).

Invasive Fungal Infections in the Critically Ill Patient

Invasive fungal infections have become an increasingly prevalent and disturbing problem in critically ill patients. The advent of broad-spectrum antibacterial therapy and immunosuppressant therapy, among other factors such as mechanical ventilation, places the intensive care patient at significant risk for infection with pathogenic fungi. Most patients who become infected with invasive fungi, especially Candida species, have been previously colonized with the offending organism, lending to the notion that colonization precedes infection inmany cases. Despite an ever-increasing array of antifungal therapy for these infections, mortality rates remain extremely high, especially when the bloodstream is the primary site of infection. In addition, a shift toward more resistant pathogens such asCandida glabrata, Candida krusei, and moldswill provide clinicianswith therapeutic challenges for many years. The wide variation in acquisition cost across antifungal agents adds an additional layer of complexity to clinical decision making. Newer antifungal agents, each with its own advantages and disadvantages, have become available in recent years. Placing each agent in its appropriate niche is a dilemma that has yet to be solved.

Papillary Adenocarcinoma of the Extrahepatic Bile Duct in a Holstein Cow

A 15-year-old female Holstein cow was presented with a history of anorexia and weight loss. Abnormal physical examination findings included poor body condition, dehydration, icterus, and photodermatitis on nonpigmented areas of the skin of the dorsum. At necropsy, the common bile duct was greatly enlarged, with thickened walls, and tightly adhered to the hepatic capsular surface and serosa of adjacent loops of the small intestine. Two sessile, yellowish, friable, well-circumscribed, cauliflower-like, bulging masses (14 and 8 cm in diameter) were attached to the inner surface of the common bile duct blocking its lumen. Microscopically, the tumor was composed of well-differentiated, columnar epithelial cells with oval or round, vesicular, basal nuclei arranged in papillary projections. Periodic acid-Schiff-positive material accumulated in the apical cytoplasm of the neoplastic cells. Immunostaining of the tumor cells was positive for cytokeratin (CK) of wide-spectrum screening and for CK 7. The diagnosis of papillary adenocarcinoma of the extrahepatic bile duct was based on the morphologic features of the neoplasm and evidence of local invasion. To the best of our knowledge, extrahepatic bile duct carcinomas have not been described in cattle.

Optimizing beta-lactam pharmacodynamics against Pseudomonas aeruginosa in adult cystic fibrosis patients

BACKGROUND

Patients with cystic fibrosis (CF) exhibit increased clearance of beta-lactams. The purpose of this study was to predict the probability of beta-lactam target attainment (PTA) against Pseudomonas aeruginosa in adult CF patients based on local microbiological data.

METHODS

CF-specific pharmacokinetic parameters were obtained from published data for aztreonam, cefepime, ceftazidime, meropenem and piperacillin-tazobactam. Pharmacodynamic modeling was used to determine the PTA for bolus, prolonged infusion, and continuous infusion regimens.

RESULTS

Prolonged infusion of meropenem 2g every 8h performed the best among all regimens tested, with a PTA of 83%. The PTA was increased with both prolonged and continuous infusion; however, no regimen reached the target PTA of >90% against P. aeruginosa in CF patients at our institution.

CONCLUSIONS

Prolonged and continuous infusion provided higher PTA than bolus for all regimens. Further investigation of novel regimens in CF patients is needed.

Utilizing Monte Carlo Simulations to Optimize Institutional Empiric Antipseudomonal Therapy

Pseudomonas aeruginosa is a common pathogen implicated in nosocomial infections with increasing resistance to a limited arsenal of antibiotics. Monte Carlo simulation provides antimicrobial stewardship teams with an additional tool to guide empiric therapy. We modeled empiric therapies with antipseudomonal β-lactam antibiotic regimens to determine which were most likely to achieve probability of target attainment (PTA) of ≥90%. Microbiological data for P. aeruginosa was reviewed for 2012. Antibiotics modeled for intermittent and prolonged infusion were aztreonam, cefepime, meropenem, and piperacillin/tazobactam. Using minimum inhibitory concentrations (MICs) from institution-specific isolates, and pharmacokinetic and pharmacodynamic parameters from previously published studies, a 10,000-subject Monte Carlo simulation was performed for each regimen to determine PTA. MICs from 272 isolates were included in this analysis. No intermittent infusion regimens achieved PTA ≥90%. Prolonged infusions of cefepime 2000 mg Q8 h, meropenem 1000 mg Q8 h, and meropenem 2000 mg Q8 h demonstrated PTA of 93%, 92%, and 100%, respectively. Prolonged infusions of piperacillin/tazobactam 4.5 g Q6 h and aztreonam 2 g Q8 h failed to achieved PTA ≥90% but demonstrated PTA of 81% and 73%, respectively. Standard doses of β-lactam antibiotics as intermittent infusion did not achieve 90% PTA against P. aeruginosa isolated at our institution; however, some prolonged infusions were able to achieve these targets.

Fulminant Invasive Pulmonary Aspergillosis After a Near-Drowning Accident in an Immunocompetent Patient

OBJECTIVE

To report on invasive aspergillosis infection in an immunocompetent adult after a near-drowning event, which allowed this pathogen to easily gain access to the human respiratory system and result in rapid, severe infection.

CASE SUMMARY

A 51-year-old female developed severe pneumonia after a near-drowning accident. Two days after admission, a bronchial alveolar lavage (BAL) was performed and was positive for Aspergillus fumigatus. After a 30-day hospital course, multiple antifungals, and various routes of administration, the patient expired.

DISCUSSION:

Pneumonia is particularly common because of the aspiration of contaminated water. Whereas pneumococci, staphylococci, and Gram-negative bacteria are all common pathogens for this type of infection, fungi such as Aspergillus spp can also be involved and may be life threatening. Typically, these cases are reported in individuals with an immunodeficiency such as from receipt of myelosuppressive chemotherapy, bone marrow transplants, or lung transplants. Despite initiation of an appropriate empirical antifungal regimen, the rapid recovery of A fumigatus from pulmonary alveolar lavage and BAL samples as well as extremely elevated levels of galactomannan and (1→3)-β-D glucan may have indicated an invasive fungal infection (IFI).

CONCLUSION:

IFIs are uncommon in immunocompetent adults, but in the event of a near-drowning accident, environmental fungi can gain access to the human respiratory system and result in rapid, severe infection. Based on this case and the others described, it appears that near-drowning patients need an early initial evaluation for IFI.

Clopidogrel treatment and the incidence and severity of community acquired pneumonia in a cohort study and meta-analysis of antiplatelet therapy in pneumonia and critical illness

Platelet activation results in the release and upregulation of mediators responsible for immune cell activation and recruitment, suggesting that platelets play an active role in immunity. Animal models and retrospective data have demonstrated benefit of antiplatelet therapy on inflammatory mediator expression and clinical outcomes. This study sought to characterize effects of clopidogrel on the incidence and severity of community-acquired pneumonia (CAP). A retrospective cohort study was conducted of Kentucky Medicaid patients (2001-2005). The exposed cohort consisted of patients receiving at least six consecutive clopidogrel prescriptions; the non-exposed cohort was comprised of patients not prescribed clopidogrel. Primary endpoints included incidence of CAP and inpatient treatment. Secondary severity endpoints included mortality, intensive care unit admission, mechanical ventilation, sepsis, and acute respiratory distress syndrome/acute lung injury. CAP incidence was significantly greater in the exposed cohort (OR 3.39, 95% CI 3.27-3.51, p < 0.0001) that remained after adjustment (OR 1.48, 95% CI 1.41-1.55, p < 0.0001). Inpatient treatment was more common in the exposed cohort (OR 1.96, 95% CI 1.85-2.07, p < 0.0001), but no significant difference remained after adjustment. Trends favoring the exposed cohort were found for the secondary severity endpoints of mechanical ventilation (p = 0.07) and mortality (p = 0.10). Pooled analysis of published studies supports these findings. While clopidogrel use may be associated with increased CAP incidence, clopidogrel does not appear to increase--and may reduce--its severity among inpatients. Because this study was retrospective and could not quantify all variables (e.g., aspirin use), these findings should be explored prospectively.

Fungal infection in heart-lung transplant recipients receiving single-agent prophylaxis with itraconazole

OBJECTIVES

Heart and lung transplant recipients are at risk for invasive fungal infections. This study evaluated the affect of single-agent antifungal prophylaxis with itraconazole on the rate of fungal infections after heart or lung transplant.

MATERIALS AND METHODS

An observational, retrospective study was performed to evaluate the rate of fungal infections in heart and lung transplant recipients at the University of Kentucky Medical Center over 4.5 years who received itraconazole as a single therapy prophylaxis.

RESULTS

Eighty-three recipients (42 heart, 41 lung) had an overall fungal infection incidence of 16.9% (14/83), while the incidence was 11.9% for heart recipients (5/42), and 22.0% for lung recipients (9/41).

CONCLUSIONS

Single-agent use with itraconazole in heart or lung transplant recipients did not affect the rate of fungal infection as compared with previous reports. The incidence of fungal infection increased significantly within 3 months after escalation of immunosuppressant for treatment of acute rejection.

Transition voltage spectroscopy and the nature of vacuum tunneling

Transition voltage spectroscopy (TVS) has been proposed as a tool to analyze charge transport through molecular junctions. We extend TVS to Au-vacuum-Au junctions and study the distance dependence of the transition voltage V(t)(d) for clean electrodes in cryogenic vacuum. On the one hand, this allows us to provide an important reference for V(t)(d) measurements on molecular junctions. On the other hand, we show that TVS forms a simple and powerful test for vacuum tunneling models.

Candidemia incidence in recipients of parenteral nutrition

BACKGROUND

The purpose of this study was to assess the incidence of candidemia in recipients of parenteral nutrition (PN) in a tertiary medical center with disease-specific guidelines for appropriate PN use.

METHODS

A retrospective, medical record/database review was conducted for adult patients who received PN in a 473-bed medical center from January 2006 to October 2008. Patients receiving PN >72 hours with no recent history of fungemia or concomitant antifungal therapy were evaluated for candidemia incidence with special interest in intensive care unit (ICU) patients. Epidemiological and clinical factors promoting candidemia development, pattern of systemic antifungal therapy use, and patient outcomes were investigated.

RESULTS

Of 286 PN recipients, 14 (4.9%) patients were diagnosed with new-onset candidemia, with an incidence rate of 1.6 episodes per 1000 hospital-days. In the subgroup of 177 ICU patients, 11 (6.2%) patients developed candidemia, with an incidence rate of 2.4 episodes per 1000 ICU-days. PN duration was significantly longer in the candidemia group, with a median of 17 (4-53) days compared with 8 (4-124) days in the noncandidemia group (P = .013). Severity of illness was defined as major to extreme in 83.5% of patients. Hospital mortality in the candidemia group was greater than in the noncandidemia group (35.7% vs 16.2%, P = .058).

CONCLUSIONS

Guidelines for PN therapy appropriately limit unnecessary use of PN but also select out severely ill patients who are at high risk for the development of candidemia. This study generates questions for future studies, including the benefits of empirical antifungal therapy in high-risk PN recipients.

Regional variations in action potential alternans in isolated murine Scn5a (+/-) hearts during dynamic pacing

AIM

clinical observations suggest that alternans in action potential (AP) characteristics presages breakdown of normal ordered cardiac electrical activity culminating in ventricular arrhythmogenesis. We compared such temporal nonuniformities in monophasic action potential (MAP) waveforms in left (LV) and right ventricular (RV) epicardia and endocardia of Langendorff-perfused murine wild-type (WT), and Scn5a(+/-) hearts modelling Brugada syndrome (BrS) for the first time.

METHODS

a dynamic pacing protocol imposed successively incremented steady pacing rates between 5.5 and 33 Hz. A signal analysis algorithm detected sequences of >10 beats showing alternans. Results were compared before and following the introduction of flecainide (10 microm) and quinidine (5 microm) known to exert pro- and anti-arrhythmic effects in BrS.

RESULTS

sustained and transient amplitude and duration alternans were both frequently followed by ventricular ectopic beats and ventricular tachycardia or fibrillation. Diastolic intervals (DIs) that coincided with onsets of transient (tr) or sustained (ss) alternans in MAP duration (DI*) and amplitude (DI') were determined. Kruskal-Wallis tests followed by Bonferroni-corrected Mann-Whitney U-tests were applied to these DI results sorted by recording site, pharmacological conditions or experimental populations. WT hearts showed no significant heterogeneities in any DI. Untreated Scn5a (+/-) hearts showed earlier onsets of transient but not sustained duration alternans in LV endocardium compared with RV endocardium or LV epicardium. Flecainide administration caused earlier onsets of both transient and sustained duration alternans selectively in the RV epicardium in the Scn5a (+/-) hearts.

CONCLUSION

these findings in a genetic model thus implicate RV epicardial changes in the arrhythmogenicity produced by flecainide challenge in previously asymptomatic clinical BrS.

Mixed lipid aggregates containing gangliosides impose different2H-NMR dynamical parameters on water environment depending on their lipid composition

Water dynamics in samples of ceramide tetrasaccharide (Gg4Cer) vesicles and GM1 ganglioside micelles at 300:1 water/lipid mole ratio were studied by using deuterium nuclear magnetic resonance (2H-NMR). GM1 imposes a different restriction on water dynamics that is insensitive to temperatures either above or below its phase transition temperature or below the freezing point of water. The calculated correlation times are in the range of 10(-10) s, typical of water molecules near to the polar groups. Pure GM1 micelles have two distinct water microenvironments dynamically characterized. Their dynamic parameters remain constant with temperature ranging from -18 to 32 degrees C, but the amount of strongly associated water is modified. By contrast, a mixture of single soluble carbohydrates corresponding to GM1 polar head group does not preserve the dynamic parameters of water hydration when the temperature is varied. Incorporation of cholesterol or lysophosphatidylcholine into GM1 micelles substantially increases the mobility of water molecules compared with that found in pure GM1 micelles. The overall results indicate that both the supramolecular organization and the local surface quality (lipid-lipid interaction) strongly influence the interfacial water mobility and the extent of hydration layers in glycosphingolipid aggregates.

Measuring the incidence of acute myocardial infarction: the problem of possible acute myocardial infarction

Variations in the ratio of "definite" to "possible" myocardial infarction for non-fatal cases were examined in studies that used World Health Organization criteria. There were large variations in this ratio, variations which appeared to be due to differences in the ascertainment of non-fatal cases of "possible" myocardial infarction, which, in turn, contributed to reported differences in the incidence of myocardial infarction. A significant proportion of cases of "possible" myocardial infarction probably do not have ischemic heart disease at all, since, in our data, cases of "possible" myocardial infarction (non-fatal) with a hospital discharge diagnosis of chest pain (undiagnosed) had a risk of death that was no worse than that in the general population. Thus the most reproducible, and possibly most accurate estimates of the incidence of myocardial infarction may come from including only fatal cases of "possible" myocardial infarction with both fatal and non-fatal cases of "definite" myocardial infarction.

Effects of a pharmacist-to-dose computerized request on promptness of antimicrobial therapy

OBJECTIVES

To examine the effects of computerized requests for pharmacist-to-dose (PTD), an advanced clinical decision support tool for dosing guidance, on antimicrobial therapy with vancomycin and aminoglycosides, describe PTD request utilization, and identify factors that may prolong this process.

DESIGN

A retrospective review was conducted of patients hospitalized from Jan 2004 to Jun 2006 with suspected pneumonia who received vancomycin, tobramycin, or gentamicin via PTD (study) or routine provider order entry (control).

MEASUREMENTS

The primary endpoint was time to pharmacist completion of PTD request. Secondary data points included medication turn-around times for first doses of vancomycin or aminoglycosides and for first doses of any antibiotic, dose adjustment for renal dysfunction, medication errors, and time of order entry. Multivariate analysis was conducted to identify predictors of total time to pharmacist verification and time to administration of first doses of vancomycin or aminoglycosides.

RESULTS

Median time for pharmacist completion of PTD requests was 29 minutes. Delays were noted in the study group (n = 49) by comparison with the control group (n = 48) for median time to first dose of vancomycin or aminoglycoside (185 vs. 138 min, p = 0.45) and for any antibiotic (134 vs. 118 min, p = 0.42), respectively. Fewer medication errors were reported in the study group (5 vs. 18 errors, p = 0.002). In a multivariate model, PTD was not significantly predictive of time to pharmacy verification or medication turn-around time.

CONCLUSIONS

Pharmacists completed pharmacist-to-dose consultations for dosing guidance of vancomycin and aminoglycosides within a median of 30 minutes. Implementation of a computerized request for clinical pharmacists to provide medication-related clinical decision support increased medication turn-around time of vancomycin and aminoglycosides and reduced medication errors. Consultation of clinical pharmacists by computerized request for initial antibiotic dosing of medications with narrow therapeutic windows is an option for medication-related clinical decision support but providers should be aware that consultation may delay medication turn-around time.

Kiss and tell: what do we know about pre- and early adolescent females who report dating? A pilot study

STUDY OBJECTIVE

To evaluate the implications of dating in pre- and early adolescent females.

DESIGN

Cross-sectional survey.

SETTING

Child psychiatry clinic; pediatric clinic; family clinic.

PARTICIPANTS

Pre- and early adolescent females (n = 80) aged 11-14 and their parents.

INTERVENTION

Pre- and early adolescent females aged 11-14 and a parent were recruited during a regular clinic visit. Pre- and early adolescent females completed a survey that included measures of dating; sensation seeking; lifetime individual and peer drug use; Attention Deficit Hyperactive Disorder, Oppositional Defiant Disorder and Conduct Disorder symptoms; and onset of menses. Parents were asked similar questions about their child's dating behaviors and peer relationships.

MAIN OUTCOME MEASURE

Association of early dating with individual and peer drug use, sensation seeking, aggressive behavior, and onset of menses.

RESULTS

In pre- and early adolescent females, dating regularly is associated with nicotine and alcohol use, sensation seeking, and aggressive behavior. Dating regularly is also associated with onset of menses and a younger age of onset of menses in those who had started menstruating. Parents under-report their child's dating practices and associated high-risk behaviors.

CONCLUSION

Early dating is associated with nicotine and alcohol use, sensation seeking, aggressive behavior, and early onset of menses in adolescent females. Questions about early dating are a simple and efficient way to open inquiry of both parents and children about high-risk behaviors in the clinic setting.

Which hydroxy? Evidence for species differences in the regioselectivity of glucuronidation in rat, dog, and human in vitro systems and dog in vivo

The glucuronidation of (1S,2R,3R,5R)-3-(hydroxymethyl)-5-[7-{[(1R,2S)-2-phenylcyclopropyl]amino}-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl]cyclopentane-1,2-diol (AZ11939714) was studied in UDP-glucuronic acid (UDPGA)-supplemented hepatic microsomes from rat, dog, and human liver. The major biliary metabolite of this compound after intraduodenal administration to a beagle dog was also studied. The techniques of HPLC, HPLC-MS and HPLC-NMR were used to characterize the glucuronides. An analysis of the proton NMR chemical shift differences between parent and metabolites was sufficient to deduce the sites of glucuronidation, although these were confirmed by 2D ROESY experiments. In dog microsomes, AZ11939714 was O-glucuronidated exclusively at the 1-position of the cyclopentanediol. This glucuronide was also the major metabolite in dog bile. In human microsomes, AZ11939714 was O-glucuronidated almost exclusively at the 3-hydroxymethyl position. Rat microsomes produced a mixture of glucuronides at the 2-position of the cyclopentanediol (major) and at the 3-hydroxymethyl position (minor). A clear qualitative species difference in the glucuronidation of AZ11939714 has been demonstrated in vitro. This may have implications for the choice of laboratory species to study the pharmacokinetics and safety of this compound.

Rhabdomyolysis during therapy with daptomycin

The use of daptomycin has been associated with an elevation in creatine phosphokinase level, with a reported incidence of 2.8% in phase III clinical trials. Published case reports have documented the presence of myopathy in patients who received daptomycin; however, there have been no previously reported cases of rhabdomyolysis in animals or humans to date. We describe a case of rhabdomyolysis during therapy with daptomycin.

Trimethoprim-sulfamethoxazole as a viable treatment option for infections caused by methicillin-resistant Staphylococcus aureus

OBJECTIVE

To review available data regarding the efficacy of trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment of infections caused by methicillin-resistant Staphylococcus aureus (MRSA).

DATA SOURCES

A MEDLINE search was performed (January 1966-December 2003) using the search terms Staphylococcus aureus , sulfamethoxazole, trimethoprim, co-trimoxazole, and methicillin resistance. Abstracts from infectious diseases meetings also were reviewed.

DATA SYNTHESIS

The reported rate of TMP-SMX resistance in S. aureus is highly variable. From a mechanistic standpoint, TMP-SMX resistance among MRSA appears to be distinct from multidrug resistance, although some anecdotal reports suggest otherwise. Clonal outbreaks of MRSA resistant to TMP-SMX have been described; of these, the Brazilian clone has more often been resistant to TMP-SMX than the Iberian clone. Rates of TMP-SMX resistance are particularly high in institutions serving large numbers of patients infected by the human immunodeficiency virus, due to increased exposure for Pneumocystis prophylaxis. Limited studies and case reports have found TMP-SMX useful against infections caused by MRSA.

CONCLUSIONS

A large body of anecdotal data, but only one randomized clinical trial, indicates the effectiveness of TMP-SMX as a treatment for MRSA infections. Double-blind, randomized controlled trials are needed to compare the two available oral agents-TMP-SMX and linezolid-against MRSA.

Linezolid for the treatment of a heteroresistant Staphylococcus aureus shunt infection

The emergence of multidrug-resistant bacteria as the cause of ventriculoperitoneal shunt infections is a disconcerting phenomenon that often requires the use of alternative antimicrobials due to resistance against commonly used agents. The following is a case report describing the successful treatment of a ventriculoperitoneal shunt infection caused by a heteroresistant strain of Staphylococcus aureus with linezolid. Linezolid may have utility in treating pediatric CNS infections due to its tolerability, excellent blood-brain barrier penetration, and activity against multiple resistant Gram-positive organisms such as S. aureus, vancomycin-resistant Enterococcus faecium and Streptococcus pneumoniae.

Rash Associated with Piperacillin/Tazobactam Administration in Infectious Mononucleosis

OBJECTIVE:

To report a case of piperacillin/tazobactam-induced rash in a patient with infectious mononucleosis.

CASE SUMMARY:

A 25-year-old white man developed a rash while receiving piperacillin/tazobactam 3.375 g intravenously every 6 hours and gentamicin for osteomyelitis complicating a left femur fracture secondary to a motorcycle accident. Due to progression of the rash following additional doses of piperacillin/tazobactam during hospitalization, the patient's antimicrobial regimen was changed to vancomycin and meropenem. Subsequently, a mononucleosis spot test was positive, and both Epstein—Barr virus (EBV) immunoglobulin (Ig) G and IgM antibodies were positive. The rash rapidly resolved with the discontinuation of piperacillin/tazobactam.

DISCUSSION:

Although the development of rash following the administration of several different antimicrobials, especially ampicillin, has been previously reported, this is the first report of piperacillin/tazobactam-induced rash in infectious mononucleosis. The rash is generally self-limiting and usually resolves within days of discontinuing the causative antimicrobial agent. An altered drug metabolism or an immune-mediated process has been suggested as the potential mechanism for rash development.

CONCLUSIONS:

Prior reports of antimicrobial-induced rash in infectious mononucleosis and a positive laboratory diagnosis of EBV in our patient with no history of penicillin allergy support the identification of piperacillin/tazobactam as the inducer of the rash. According to the Naranjo probability scale, the association of piperacillin/tazobactam with the rash was classified as probable.

Micellar anisometry in lyotropic uniaxial nematic phases studied by transversal NMR relaxation dispersion

A new method, based on the measurement of the (23 )( )Na nuclei spin-spin NMR relaxation times ( T2 ), is proposed to investigate the shape of micelles in lyotropic nematic phases. We investigate the ternary lyotropic mixture of sodium dodecyl sulfate, 1-decanol, and water by using the NMR technique, measuring T2 in the two lyotropic uniaxial nematic phases. The characteristic relaxation time curves of each particular phase are analyzed by considering that they are constituted by a superposition of exponential decays with typical characteristic times: in a sense, a T2 spectroscopy. The analysis of the T2 dispersion profiles in both the uniaxial nematic calamitic and discotic phases indicates that our results can be interpreted in terms of the model of intrinsically biaxial micelles in all the nematic phases.

Voriconazole treatment of disseminated paecilomyces infection in a patient with acquired immunodeficiency syndrome

We describe a patient with poorly controlled, multidrug-resistant human immunodeficiency virus disease who developed >20 skin lesions caused by Paecilomyces lilacinus. The lesions failed to improve during treatment with oral itraconazole, amphotericin B, and amphotericin B lipid complex but improved during treatment with voriconazole.

Conservation of RET proto-oncogene splicing variants and implications for RET isoform function

The RET proto-oncogene encodes a receptor tyrosine kinase required for development of the kidney and neural crest-derived cell types. Alternative splicing of the 3' exons of human RET results in three protein isoforms with distinct C-termini: RET9, RET51, and RET43. These RET isoforms show differential binding to downstream adapter molecules, suggesting they may have distinct signaling functions. We have characterized Ret 3' sequences in mouse and investigated alternative splicing of this region. We found that the organization of Ret 3' sequences is very similar to human RET. The mouse locus also has alternatively spliced C-terminal coding regions, and the sequences corresponding to RET9 and RET51 are highly conserved in both position and sequence with the human locus. Further, we compared the predicted C-terminal amino acids of RET9 and RET51 in seven vertebrate species, and found that they are well conserved. We have identified sequence encoding a putative ret43 isoform in mouse, however the predicted amino acid sequence showed low homology to human RET43. Our data suggest that RET isoforms are evolutionarily highly conserved over a broad range of species, which may indicate that each isoform has a distinct role in normal RET function.