Clinical Applicability of in vivo Reflectance Confocal Microscopy for the Diagnosis of Actinic Keratoses

BACKGROUND In vivo reflectance confocal microscopy (RCM) has been used for evaluation of the morphologic features of nonmelanoma skin cancer. The application of RCM for diagnosis of basal cell carcinoma has been reported; however, the evaluation of actinic keratoses (AKs) has only been the subject of preliminary studies.
STUDY GOAL The goal of this study was to evaluate the applicability of RCM in the diagnosis of AK in correlation with routine histology.
MATERIALS AND METHODS Forty-four Caucasians with a minimum of one AK participated in this study. Evaluation consisted of clinical examination, RCM, and routine histology, including a total of 46 AKs in the final analysis. Ten normal skin sites served as controls. RCM features of AK included parakeratosis, architectural disarray, and keratinocyte pleomorphism. Following blinded evaluations, sensitivity/specificity, kappa analysis, and Spearman's correlation were performed on all parameters.
RESULTS Sensitivity/specificity values of RCM features ranged from 80% to 98.6%. The presence of architectural disarray and cellular pleomorphism appeared to be the best predictor of AK.
CONCLUSION In summary, RCM may be a promising technology for the noninvasive detection of AK and as adjunct tool to clinical diagnosis and monitoring. However, the preliminary nature of this study warrants further investigations.     

Suppression of Atrial Tachyarrhythmias by Pacing

Pace‐Suppression of AF. Introduction: Treatment of atrial tachyarrhythmias (ATs) remains difficult in many patients. Accordingly, new therapeutic approaches for AT suppression are evaluated. Atrial pacing may prevent ATs by modifying the electrophysiologic conditions required for sustained ATs. Methods and Results: New pacing algorithms for prevention of AT are aimed at permanent overdrive suppression of arrhythmic activity, reduction of dispersion of atrial refractoriness produced by short‐long cycles, more aggressive overdrive pacing after spontaneous sinus conversion to prevent early reinitiation of ATs, and prevention of inadequate rate decay in patients with vagally induced ATs. AT prevention may be achieved by dedicated atrial pacing sites, e.g., pacing at the insertion of Bachmann's bundle or biatrial pacing, which compensates for interatrial conduction delay. Preexciting regions of critical conduction delay, pacing at the triangle of Koch or coronary sinus os, and dual‐site right atrial pacing have shown antiarrhythmic effects. Atrial preventive pacing and pharmacologic treatment may work synergistically in the concept of hybrid therapy. To prevent atrial electrical remodeling, early termination of AT seems desirable. This may be achieved by implanted devices that automatically detect ATs and provide atrial antitachycardia pacing for organized ATs. Initial studies showed that regular AT can automatically be terminated in approximately 50% of treated episodes. Conclusion: Pacing for prevention of AT and termination of organized AT episodes may become important steps within the concept of hybrid therapy of AT. However, their clinical efficacy and optimal patient selection remain to be evaluated in prospective, well‐designed clinical trials.     

Stereological estimation of the volume weighted mean volumes of alveoli and acinar pathways in the rat lung to characterise alterations after ischaemia/reperfusion

The aim of this study was to characterise pulmonary reimplantation injury in isolated, perfused rat lungs following 2 h of cold ischaemia, and 50 min. of in vitro reperfusion. The effects of 2 differently composed lung preservation solutions (low potassium Euro-Collins and Celsior; each n=5) were examined in comparison with untreated, nonischaemic control lungs (n=3). After fixation by vascular perfusion and tissue collection by systematic random sampling, the volume weighted mean volume (_v) of alveoli and acinar pathways was estimated by light microscopic stereology using the method of point sampled intercepts in plastic embedded, Azan-stained material. Significantly higher _v of alveoli and acinar paths was found in the Celsior group than in Euro-Collins preserved lungs. However, in the controls the size of acinar pathways was similar to Celsior preserved lungs whereas alveolar size was comparable to preservation with Euro-Collins. The between-animal coefficient of variation of alveoli was very low in controls and Celsior preserved but higher in the Euro-Collins group. Size distribution of alveoli and acinar paths in 15 size classes was largely homogeneous in all groups tested. In the Euro-Collins group the fractions of both class 1-alveoli and class 1-acinar paths significantly exceeded those of the other groups. Widely expanded alveoli (size classes 13–15) only occurred after preservation with Celsior whereas wider acinar paths (size class 15) were found in the Celsior group and in the controls. It is concluded that lung preservation with low-potassium Euro-Collins and Celsior solutions may act differently on distinct spaces in the distal gas-exchange regions of lungs. This may be due to selective effects on pulmonary surfactant activity and on elastic tissue elements in the alveolar ducts, respectively. Additionally, the method of point sampled intercepts is considered to be an efficient tool to evaluate the effects of different preservation solutions on lung parenchyma.     

Ischemia Induces Significant Changes in Purine Nucleoside Concentration in the Retina-Choroid in Rats

Adenosine, produced from the decomposition of adenosine triphosphate, is believed to provide protective effects during ischemia. On the other hand, adenosine metabolites may serve as precursors for oxygen free radical formation. The time course of formation of adenosine and its purine metabolites was studied during retinal ischemia in rats. Concentrations of adenosine and its purine nucleoside metabolites inosine, hypoxanthine, and xanthine in the retina-choroid of ketamine/xylazine-anesthetized rats were measured during retinal ischemia using high performance liquid chromatography. Quantitative measurements were made possible in the small tissue mass through the use of internal standards. Ischemia was induced by ligation of the central retinal artery. In each rat, one eye was ischemic while the other served as a non-ischemic control. Eyes were frozen in situ at 1, 5, 10, 20, 30, 60, and 120 min of ischemia. The retina-choroid was then removed from the frozen eyes and analysed. Significant increases in the concentrations of adenosine, inosine, and hypoxanthine in ischemic compared to control retina-choroid were detectable within 1 to 5 min of the onset of ischemia, and within 10 min for xanthine. Increase in adenosine concentration in ischemic relative to control retina-choroid plateaued at 30 min of ischemia, while inosine and hypoxanthine concentrations increased continuously. The increase in xanthine concentration was exponential throughout the measurement period. This study documented the time-related changes in purine nucleoside concentration during ischemia. Prolonged ischemia results in ongoing production of xanthine, which by serving as a precursor for oxygen free radical formation, could be a pathogenic factor in prolonged retinal ischemia.     

Pulmonary Vein Isolation Supported by MRI‐Derived 3D‐Augmented Biplane Fluoroscopy: A Feasibility Study and a Quantitative Analysis of the Accuracy of the Technique

MRI‐Derived 3D‐Augmented Biplane Fluoroscopy . Background: Despite the advancement of technology in electroanatomic mapping systems (EAMS), fluoroscopy remains a necessary, basic imaging modality for electrophysiology procedures. We present a feasibility study of new software that enables 3D‐augmented fluoroscopy in biplane catheterization laboratories for planning and guidance of pulmonary vein isolation (PVI). The computer‐assisted overlay registration accuracy was assessed in a clinical setting using an automatic calculation of overlay projection geometry that was derived from hardware sensors in C‐arms, detectors, and patient table. Methods: Consecutive patients (n = 89) underwent left atrium (LA) magnetic resonance imaging MRI scan prior to PVI. Ideal ablation lines encircling the ipsilateral pulmonary veins (PVs) at antral level were drawn onto the segmented LA surface. The 3D‐model was superimposed onto biplane fluoroscopy and matched with angiographies of LA and PVs. Three‐dimensional‐overlay projection geometry was automatically calculated from C‐arm, detectors, and table sensors. Accuracy of technique was assessed as alignment of MRI‐derived 3D overlay and angiographic LA/PV anatomy. Integrity of registered overlay was quantified using landmark measurements. Results: Alignment offsets were 1.3 ± 1.5 mm in left PV, 1.2 ± 1.5 mm in right PV, and 1.1 ± 1.4 mm in LA roof region. Bravais–Pearson correlation of the landmark measurements was r = 0.978 (s  < 0.01), mean offset between landmark distance measurements was 1.4 ± 0.78 mm. Average time needed for overlay registration was 9.5 ± 3.5 seconds. Conclusions: MRI‐derived 3D‐augmented fluoroscopy demonstrated a high level of accuracy when compared with LA/PV angiography. The new system could be especially useful to guide procedures not supported by EAMS, such as cryotechnique PVI. (J Cardiovasc Electrophysiol, Vol. 24, pp. 113‐120, February 2013)     

Information processing during sleep: the effect of olfactory stimuli on dream content and dream emotions

Research has shown that external stimuli presented during sleep can affect dream content, thus reflecting information processing of the sleeping brain. Olfactory stimuli should have a stronger effect on dream emotions because their processing is linked directly to the limbic system. Because selective olfactory stimulation does not increase arousal activity, intense olfactory stimulation is therefore a prime paradigm for studying information processing during sleep. Fifteen healthy, normosmic volunteers were studied by intranasal chemosensory stimulation during rapid eye movement sleep based on air-dilution olfactometry. For olfactory stimulation, hydrogen sulphide (smell of rotten eggs) and phenyl ethyl alcohol (smell of roses) was used and compared with a control condition without stimulation. The olfactory stimuli affected significantly the emotional content of dreams: the positively toned stimulus yielded more positively toned dreams, whereas the negative stimulus was followed by more negatively toned dreams. Direct incorporations, i.e. the dreamer is smelling something, were not found. The findings indicate that information processing of olfactory stimuli is present in sleep and that the emotional tone of dreams can be influenced significantly depending upon the hedonic characteristic of the stimulus used. It would be interesting to conduct learning experiments (associating specific odours with declarative material) to study whether this declarative material is incorporated into subsequent dreams if the corresponding odour cue is presented during sleep. It would also be interesting to study the effect of positively toned olfactory stimuli on nightmares.     

Managing Difficult Common Bile Duct Problems With the Help of the Interventional Radiologist

Surgery is the mainstay of therapy for disorders of the common bile duct. In recent years, however, numerous radiological biliary interventional procedures have been developed. Sufficient experience with these techniques has now been accumulated such that the role of these procedures is now more clearly defined. A variety of transhepatic and transcholecystic biliary manipulations is described as an overview of the value of these procedures in difficult common bile duct disorders.     

Computer-Assisted Pacemaker Management Systems: Three Years of Clinical Experience

The implantation of large numbers of cardiac pacemakers and the increasing sophistication in engineering techniques has resulted in the demand for computer-assisted pacemaker management systems to remain on top of the available programmable features of the pacers as well as being able to access the follow-up data of pacemaker patients. A pacemaker patient management systems is introduced (PATIENTLOG™) that has been used in the clinical environment for a number of years. The menu-guided program is easy to handle and features a patient card for administration data, an implantation card for the technical data of the pacer, and a follow-up card where a large number of follow-ups can be stored side by side which are easily graphically displayable. An extensive statistical program, letter functions, automatic back-up and on-line communication with external equipment through an RS 232C interphase and a parallel adapter are available. The data base in Frankfurt holds 8,000 patients, 10,000 interventions and more than 30,000 follow-ups, the existing data base needs 20 M bytes storage space. Up to 96 different pacer types with their specific features can be introduced into the system. Software and hardware design complies with the recommendation of the NASPE Computer Committee.