Affective processing of loved faces: contributions from peripheral and central electrophysiology

Research on the neural mechanisms of face identity constitutes a fruitful method to explore the affective contributions to face processing. Here, we investigated central and peripheral electrophysiological indices associated with the perception of loved faces. Subjects viewed black-and-white photographs of faces that belonged to one of five categories: loved ones, famous people, unknown people, babies, and neutral faces from the Eckman and Friesen system. Subcategories of loved faces included romantic partner, parents, siblings, second-degree relatives, and friends. Pictures were presented in two separate blocks, differing in viewing time (0.5s vs. 4s), inter-stimulus interval (1.2s vs. 18s), and number of face presentations (200 vs. 50). Heart rate, skin conductance, electromyography of the zygomatic muscle, and event-related potentials (ERPs) were obtained while participants passively viewed the pictures. Subjective picture ratings of valence, arousal, and dominance were obtained at the end of the experiment. Both central and peripheral electrophysiological measures differentiated faces of loved ones from all other categories by eliciting higher heart rate, skin conductance, and zygomatic activity, as well as larger amplitudes of the late ERP components P3 and LPP. Loved faces also resulted in higher valence and arousal, but lower dominance ratings. Additional differences were found among subcategories of loved faces. Faces of romantic partners elicited higher physiological (skin conductance and zygomatic activity) and subjective (emotional arousal) responses than parents, siblings, or friends, suggesting that looking at the image of someone we love evokes strong positive affect and emotional/cognitive arousal that go beyond a feeling of familiarity or simple recognition.

KARDIA: a Matlab software for the analysis of cardiac interbeat intervals

This article presents KARDIA, a Matlab (MathWorks Inc., MA) software developed for the analysis of cardiac interbeat interval (IBI) data. Available functions are called through a graphical user interface and permit the study of phasic cardiac responses (PCRs) and the estimation of time and frequency domain heart rate variability (HRV) parameters. Scaling exponents of heartbeat fluctuations are calculated with the detrended fluctuation analysis (DFA) algorithm. Grand average and individual subject results can be exported to spreadsheets for further statistical analysis. KARDIA is distributed free of charge under the terms of GNU public license so that other users can modify the code and adjust the program's performance according to their own scientific requirements.

The dynamics of cardiac defense: from attention to action

The attentional and motivational significance of cardiac defense is examined in two studies. In Study 1, cardiac defense was evoked by an intense acoustic stimulus in the context of either a visual search or a memory search task using letters as stimuli. Results showed a potentiation of the long latency acceleration of cardiac defense in the visual search task. In Study 2, participants performed the same visual search task using pleasant, neutral, and unpleasant pictures as stimuli. Results showed a further potentiation of the long latency acceleration of cardiac defense when the visual search task was performed with unpleasant, compared to pleasant or neutral pictures. These results indicate that cardiac defense has both attentional and motivational contributions, where the attentional significance is related to increased sensory processing, whereas the motivational significance is associated with preparation for active defense.

Communalities and differences in fear potentiation between cardiac defense and eyeblink startle

This study examines similarities and differences in fear potentiation between two protective reflexes: cardiac defense and eyeblink startle. Women reporting intense fear of animals but low fear of blood or intense fear of blood but low fear of animals viewed pictures depicting blood or the feared animal for 6 s in 2 separate trials in counterbalanced order. An intense burst of white noise, able to elicit both a cardiac defense response and a reflexive startle blink, was presented 3.5 s after picture onset. Both cardiac and blink responses were potentiated when highly fearful individuals viewed fearful pictures. However, differences appeared concerning picture order. This pattern of results indicates communalities and differences among protective reflexes that are relevant for understanding the dynamics of emotional reflex modulation.

Fear-conditioned respiration and its association to cardiac reactivity

This study aimed to investigate ventilatory correlates of conditioned fear responses. Respiratory, end-tidal carbon dioxide pressure (PetCO(2)) and heart rate changes were studied in a differential fear-conditioning paradigm. Forty-two participants viewed pictures of faces. One picture (CS+) was followed by a human scream (US) during the acquisition phase, but not in a subsequent extinction phase. Conditioning of PetCO(2) (decrease), respiratory cycle time (decrease) and inspiratory duty time (increase) was established and subsequently extinguished. When participants were clustered according to their conditioned PetCO(2) responses during acquisition, only a group showing a conditioned decrease in PetCO(2) showed also a differential cardiac acceleration, a decrease in expiratory duration and an increase in inspiratory duty time in response to the CS+. These results suggest that preparation for defensive action is characterized by a tendency towards hyperventilation and cardiac acceleration.

The importance of sample size, log-mean ratios, and intrasubject variability in the acceptance criteria of 108 bioequivalence studies

PURPOSE

Fulfilling bioequivalence criteria with highly variable drugs is difficult. The aim of this study was to compare the importance of sample size, intrasubject variability, and the point estimate of test and reference formulations with regard to meeting bioequivalence (BE) criteria [maximum observed plasma concentration (C(max)) and area under the concentration-time curve (AUC)].

METHODS

We compared 137 pairs of data from BE studies with a conventional number of subjects, approximately 31-32 volunteers, developed in the last 10 years.

RESULTS

The third part of the studies failed to demonstrate BE, in part due to an unacceptable difference between the mean ratios (T/R) (18) but also due to high variability with small differences between formulations (17). Increasing the number of subjects is hard to justify, and expanding the confidence interval (CI) was insufficient for the most highly variable drugs.

CONCLUSIONS

Therefore, for low-variable drugs, the difference between formulations was the cornerstone of the fulfillment of BE criteria, but for highly variable drugs, the intrasubject coefficient of variability (ICV) was decisive. Our proposal is that for highly variable drugs that fall outside BE 90% CI limits could result in BE in the absence of formulation effect and maximal differences between formulations below 20%.

[The International Affective Digitized Sounds (IADS): Spanish norms]

The International Affective Digitized Sounds (IADS): Spanish Norms. The Spanish norms for the International Affective Digitized Sounds (IADS) are reported. The IADS is a standardized set of 110 digitalized sounds which are both reliable and valid for the experimental study of emotional processes. The construction of the IADS is based on Peter J. Lang's dimensional model of emotions. Participants were 1.716 university students (1.136 women) who assessed the sounds using the three scales of the Self-Assessment Manikin: affective valence, arousal, and dominance. The results show a distribution of the sounds, within the bidimensional plot defined by valence and arousal, similar to the North-American student population with a typical boomerang shape. No significant differences were found when comparing men and women nor when comparing the Spanish and North-American samples in the total set of sounds. The results are discussed in relation to the International Affective Picture System (IAPS). The norms for each of the 110 sounds are presented in an annexed table.

Development of a simplified simulation model for performance characterization of a pixellated CdZnTe multimodality imaging system

Current requirements of molecular imaging lead to the complete integration of complementary modalities in a single hybrid imaging system to correlate function and structure. Among the various existing detector technologies, which can be implemented to integrate nuclear modalities (PET and/or single-photon emission computed tomography with x-rays (CT) and most probably with MR, pixellated wide bandgap room temperature semiconductor detectors, such as CdZnTe and/or CdTe, are promising candidates. This paper deals with the development of a simplified simulation model for pixellated semiconductor radiation detectors, as a first step towards the performance characterization of a multimodality imaging system based on CdZnTe. In particular, this work presents a simple computational model, based on a 1D approximate solution of the Schockley-Ramo theorem, and its integration into the Geant4 application for tomographic emission (GATE) platform in order to perform accurately and, therefore, improve the simulations of pixellated detectors in different configurations with a simultaneous cathode and anode pixel readout. The model presented here is successfully validated against an existing detailed finite element simulator, the multi-geometry simulation code, with respect to the charge induced at the anode, taking into consideration interpixel charge sharing and crosstalk, and to the detector charge induction efficiency. As a final point, the model provides estimated energy spectra and time resolution for (57)Co and (18)F sources obtained with the GATE code after the incorporation of the proposed model.

Cardiac defense: From attention to action☆

The concept of defense relates to the idea that organisms react physiologically to the presence of danger or threat in order to protect themselves from potential injury or death. This article reviews the literature on cardiac defense, a specific defense reaction that has a long tradition in psychophysiological research. The review begins with a brief analysis of the two traditional approaches to understand this autonomic response: the cognitive -- linked to Pavlov, Sokolov, and Graham's work on sensory reflexes -- and the motivational -- linked to Cannon and Selye's work on the concepts of activation and stress. Then, the classic model of cardiac defense and its basic assumptions concerning differentiation from other cardiac reflexes -- namely orienting and startle -- are presented. A critical analysis of these assumptions follows centered on evidence from a systematic research of the cardiac response to intense acoustic stimulation. Finally, an integrative model of cardiac defense is presented which emphasizes the dynamic nature of this defense reaction - characterized by a complex pattern of heart rate changes with accelerative and decelerative components, with sympathethic and parasympathetic influences, and with both attentional and motivational significance - providing a new framework in which the two opposite traditional approaches can be reconciled.

A phase I, dose-finding study of irinotecan (CPT-11) short i.v. infusion combined with fixed dose of 5-fluorouracil (5-FU) protracted i.v. infusion in adult patients with advanced solid tumours

PURPOSE

Irinotecan (CPT-11) and 5-fluorouracil (5-FU) are effective cytotoxic agents in the treatment of solid tumours. Continuous i.v. infusion (CI) of 5-FU is significantly more active and better tolerated than bolus i.v. 5-FU. This phase I pharmacokinetic and clinical study evaluated escalating CPT-11 doses administered every 3 weeks combined with a fixed dose of 5-FU CI over 14 days to find the maximum tolerated dose (MTD) of this combined chemotherapy.

PATIENTS AND METHODS

Patients with solid tumours showing failure with previous standard treatment or for whom no established curative therapy existed received CPT-11 i.v. over 90 min (six dose levels were evaluated: 150, 175, 200, 250, 300 and 350 mg/m(2)) plus a fixed dose of 5-FU CI 250 mg/m(2) per day over 14 days. If the MTD was not reached at CPT-11 level 6, then 5-FU was increased to 300 mg/m(2). In step 2, 5-FU was administered as a true protracted infusion at the recommended dose found during step 1. In step 3, the recommended dose of CPT-11 was divided and administered in a weekly schedule for 4 weeks combined with a fixed dose of 5-FU CI 250 mg/m(2), and then followed by 2-5 weeks rest.

RESULTS

Neutropenia and diarrhoea were the main toxicities, leading to early termination of infusion in three of six patients in level 7. Therefore, CPT-11 350 mg/m(2) + 5-FU 250 mg/m(2) CI over 14 days was identified as the recommended dose. In step 2, CPT-11 dose had to be reduced to 300 mg/m(2) due to toxicity. The weekly schedule of CPT-11 75 mg/m(2) + 5-FU 250 mg/m(2) CI was feasible with only one patient experiencing severe diarrhoea. No interactions were found in the kinetics parameters of CPT-11 or 5-FU for the different dose levels studied.

CONCLUSION

CPT-11 300 mg/m(2) + 5-FU 250 mg/m(2) protracted infusion is the recommended dose for phase II trials, neutropenia and diarrhoea being the dose-limiting toxicities.

Tachyphylaxis following regular use of formoterol in exercise-induced bronchospasm

BACKGROUND

Formoterol is a highly effective therapeutic agent in the prevention of exercise-induced bronchospasm (EIB). Regular use of beta-adrenergic drugs may result in a reduction in the protective effect afforded by these bronchodilators against bronchoconstrictor stimuli. It is unknown whether this effect extends to formoterol and exercise.

METHODS

We performed a randomized, double-blind, parallel clinical trial in 19 patients with EIB. Each patient received inhaled formoterol or placebo twice daily during 4 weeks. Patients performed two exercise tests in a cycle ergometer on the 1st, 14th, and 28th study days separated 3 hours from each other. A dose of formoterol was given 30 min prior to the 2nd test.

RESULTS

There were significant differences in bronchoprotection between days 1 and 14 (p = .012) and between days 1 and 28 (p = .012) in the formoterol group. No differences were found in the placebo group. The evolution of the bronchoprotection index was also significantly different between the formoterol and the placebo group (p = .002) from day 1 to 28.

CONCLUSIONS

Tachyphylaxis developed to the protective effect of formoterol against EIB after 4 weeks of regular dosing. Tolerance was already found on day 14, though not progressive. Formoterol should be recommended only as needed in EIB.

Clinical outcome after radiofrequency catheter ablation of focal atrial fibrillation triggers

INTRODUCTION

Ablative therapy for atrial fibrillation (AF) by targeting initiating triggers, usually in or around the pulmonary veins, has been reported by several centers. Evidence for an overall improvement in quality of life (QOL) and amelioration of symptoms is lacking.

METHODS AND RESULTS

Seventy-one patients undergoing attempted ablation of focal AF were followed for 60+/-33 weeks. QOL and symptom questionnaires were completed 1 month before and 6 months after electrophysiologic study. Twenty-three patients (32%) underwent electrophysiologic mapping but no ablation because of either insufficient or multifocal ectopy; the other 48 patients (68%) underwent attempted ablation. Sixteen of 48 patients (33%) undergoing ablation, or 16 (23%) of 71 on an intention-to-treat basis, were found at last follow-up to have persistent sinus rhythm without antiarrhythmic drugs. Patients who underwent mapping without ablation reported no improvements in any QOL or symptom score, whereas patients who had long-term successful ablation had significant improvements in all six QOL measures. Interestingly, patients who developed AF recurrence after ablation still reported significant improvements in 4 of 6 QOL measures. Four of 48 patients (8.3%) undergoing ablation developed pulmonary vein stenosis.

CONCLUSION

Paroxysmal AF can be treated successfully in some patients by ablating initiating triggers in the pulmonary veins; however, in our experience the recurrence rate (32/48 [68%]) and risk of pulmonary vein stenosis (8%) after ablation are high. Patients with recurrent AF after ablation of focal AF triggers have significant improvement in QOL and symptoms compared with before ablation. Patients and their physicians should carefully balance the risks and benefits before considering ablation.

Bioequivalence of allopurinol and its metabolite oxipurinol in two tablet formulations

OBJECTIVE

To test for the bioequivalence of two allopurinol 300 mg tablet formulations (generic allopurinol (Normon) and Zyloric tablets).

METHOD

A single dose study was carried out in 24 healthy volunteers with a two-sequence, crossover block-randomized design. Blood samples were taken prior to each administration and at 19 points within 72 h after the dose. Plasma concentrations of allopurinol and oxypurinol were determined by HPLC. The pharmacokinetic parameters Cmax and Tmax were obtained directly from plasma allopurinol and oxypurinol concentrations. ke was estimated by log-linear regression and AUC was calculated by the linear trapezoidal rule for both allopurinol and oxypurinol. The pharmacokinetic parameters AUC and Cmax were tested for equivalence after log-transformation of data. Differences of Tmax were evaluated by a non-parametric test. The 90% standard confidence intervals of the mean values for the test/reference ratios were for AUC and for Cmax, within the acceptable bioequivalence limits of 0.80-1.25 for both allopurinol and oxypurinol.

CONCLUSION

The two formulations are bioequivalent and therefore interchangeable.

Gender differences in the disposition of metronidazole

OBJECTIVE

Gender is usually considered to be one of the factors influencing disposition of drugs, but the evidence available is sometimes conflicting and information for a large number of frequently used drugs is lacking. An evaluation of sex differences in the disposition ofmetronidazole was carried out during a bioequivalence study.

SUBJECTS AND METHODS

Twenty-four volunteers (12 males and 12 females) were included in an open, single-dose, two-sequence, crossover randomized trial with a one-week washout interval. All volunteers received in each period, a single 250 mg dose of one of the two study formulations of metronidazole. Venous blood samples were collected immediately before and at 15 time points in an 48-hour interval after drug administration; metronidazole concentrations were determined by HPLC. Non-compartmental pharmacokinetic analysis was performed and log-transformed AUC(0-infinity) and Cmax were tested for bioequivalence. Sex differences were evaluated by means of a 4-factor (sex, sequence, treatment and period) ANOVA.

RESULTS

The studied formulations were found bioequivalent according to international standards: average 90% confidence interval for AUC(0-infinity) was 98 to 104 and for Cmax 93 to 115. After correction for the administered dose/kg, AUC was about 12% lower in females than in males (p = 0.0388) and, therefore, a higher calculated oral Cl/kg was found in females. Apparent distribution volume, after correction for weight, was significantly higher in males (p = 0.0019). Metronidazole half-life and MRT were shorter in females than in males (p - 0.0014 and p = 0.0002, respectively).

CONCLUSIONS

Data obtained in this study suggest that metronidazole clearance in females is about 12% higher than in males although these differences are probably of no clinical relevance.

Gelatin microspheres crosslinked with D,L-glyceraldehyde as a potential drug delivery system: preparation, characterisation, in vitro and in vivo studies

To overcome the restriction in using crosslinked gelatin in the pharmaceutical field, D,L-glyceraldehyde (GAL), a non-toxic crosslinking agent, was proposed. Gelatin microspheres crosslinked with different concentrations of GAL (0.5, 1 or 2%, w/v) and for different time periods (1 or 24 h) were prepared. The effect of the preparation variables was evaluated analysing the extent of crosslinking, the morphological aspect, the particle size and the swelling behaviour. To evaluate the pharmaceutical properties, an antihypertensive drug, clonidine hydrochloride, was chosen as drug model and loaded into the microspheres. Either the increase of the crosslinker concentration or of the crosslinking time period decreased both the swelling and the in vitro drug release processes of the microspheres. After the subcutaneous injection, the loaded microspheres crosslinked with the lowest GAL concentration (0.5%, w/v) or for the shortest time period (1 h) showed a reduction of systolic blood pressure (SBP) similar to that recorded with a clonidine hydrochloride solution having the same drug concentration. Instead, the microspheres crosslinked for 24 h with concentrations of GAL higher than 0.5% (w/v) produced a more gradual and sustained SBP reduction and the antihypertensive effect was maintained until 52-72 h. The biocompatibility studies showed that the microspheres crosslinked with GAL are well tolerated in vivo. These results suggest the potential application of gelatin microspheres crosslinked with GAL as a suitable drug delivery system for the subcutaneous administration.

Effect of zaleplon on digoxin pharmacokinetics and pharmacodynamics

The pharmacokinetics and pharmacodynamics of digoxin alone and digoxin plus zaleplon were studied. Healthy, nonsmoking men between 18 and 45 years of age were given a single oral dose of digoxin 0.375 mg daily on days 1 through 9. On days 10 through 14, the subjects received digoxin 0.375 mg plus oral zaleplon 10 mg daily. Blood samples were obtained on days 3, 5, 8, 9, and 14, and serum digoxin concentration data were analyzed by model-independent pharmacokinetic methods. Blood pressure, heart rate, PR interval, and QTc interval were recorded to determine the effect of zaleplon on digoxin pharmacodynamics. A total of 20 men completed the study. Maximum serum digoxin concentration and area under the serum digoxin concentration-versus-time curve from 0 to 24 hours met bioequivalence test criteria. There were no significant differences in QTc or PR interval between days 9 (digoxin alone) and 14 (digoxin plus zaleplon), and there were no clinically important changes from baseline to the study's end in vital signs, physical examination findings, or ECG results for individual subjects. Eighteen percent of the subjects who received digoxin alone and 35% of those who received digoxin plus zaleplon reported one or more adverse effects; all were mild and resolved quickly. Zaleplon had no significant effects on selected pharmacokinetic and pharmacodynamic properties of digoxin.

Cryothermal ablation of the slow pathway for the elimination of atrioventricular nodal reentrant tachycardia

BACKGROUND

We report the first successful slow pathway ablation using a novel catheter-based cryothermal technology for the elimination of atrioventricular nodal reentrant tachycardia (AVNRT).

METHODS AND RESULTS

Eighteen patients with typical AVNRT underwent cryoablation. Reversible loss of slow pathway (SP) conduction during cryothermy (ice mapping) was demonstrated in 11 of 12 patients. Because of time constraints, only 2 sites were ice mapped in 1 patient. Seventeen of 18 patients had successful cryoablation of the SP. One patient had successful ice mapping of the SP, but inability to cool beyond -38 degrees C prevented successful cryoablation. A single radiofrequency lesion at this site eliminated SP conduction. No patient has had recurrent AVNRT over 4.9+/-1.7 months of follow-up. During cryoablation, accelerated junctional tachycardia was not seen and was therefore not available to guide lesion delivery. Adherence of the catheter tip during cryothermy (cryoadherence) allowed atrial pacing to test for SP conduction. Cryoablation in the anterior septum produced inadvertent transient PR prolongation consistent with loss of fast pathway conduction in 1 patient and transient (6.5 seconds) 2:1 AV block in another. On rewarming, the PR interval returned to normal, and the AV nodal effective refractory period was unchanged in both. Accelerated junctional tachycardia was seen on rewarming in both but not during cryothermy.

CONCLUSIONS

Cryothermal ablation of the SP was achieved in patients with this novel technique. Successful ice mapping of both the SP and fast pathway was demonstrated. The ability to test the functionality of specific ablation sites before production of a permanent lesion may eliminate inadvertent AV block.