Neurolisteriosis mimicking herpes simplex encephalitis in an immunocompromized patient

Brain MRI was performed in an immunocompromized febrile and lethargic patient, revealing an asymmetric bilateral temporal lobe involvement, strongly suggestive of herpetic encephalitis. Nevertheless, PCR in CSF for Listeria monocytogens was positive. This case implies that Listeria might be considered in patients with clinical and imaging suspicion of herpetic encephalitis.     

Stem cell sources for vascular tissue engineering and regeneration

This review focuses on the stem cell sources with the potential to be used in vascular tissue engineering and to promote vascular regeneration. The first clinical studies using tissue-engineered vascular grafts are already under way, supporting the potential of this technology in the treatment of cardiovascular and other diseases. Despite progress in engineering biomaterials with the appropriate mechanical properties and biological cues as well as bioreactors for generating the correct tissue microenvironment, the source of cells that make up the vascular tissues remains a major challenge for tissue engineers and physicians. Mature cells from the tissue of origin may be difficult to obtain and suffer from limited proliferative capacity, which may further decline as a function of donor age. On the other hand, multipotent and pluripotent stem cells have great potential to provide large numbers of autologous cells with a great differentiation capacity. Here, we discuss the adult multipotent as well as embryonic and induced pluripotent stem cells, their differentiation potential toward vascular lineages, and their use in engineering functional and implantable vascular tissues. We also discuss the associated challenges that need to be addressed in order to facilitate the transition of this technology from the bench to the bedside.     

Criticality Hidden in Acoustic Emissions and in Changing Electrical Resistance during Fracture of Rocks and Cement-Based Materials

Acoustic emissions (AE) due to microcracking in solid materials permit the monitoring of fracture processes and the study of failure dynamics. As an alternative method of integrity assessment, measurements of electrical resistance can be used as well. In the literature, however, many studies connect the notion of criticality with AE originating from the fracture, but not with the changes in the electrical properties of materials. In order to further investigate the possible critical behavior of fracture processes in rocks and cement-based materials, we apply natural time (NT) analysis to the time series of AE and resistance measurements, recorded during fracture experiments on cement mortar (CM) and Luserna stone (LS) specimens. The NT analysis indicates that criticality in terms of electrical resistance changes systematically precedes AE criticality for all investigated specimens. The observed greater unpredictability of the CM fracture behavior with respect to LS could be ascribed to the different degree of material homogeneity, since LS (heterogeneous material) expectedly offers more abundant and more easily identifiable fracture precursors than CM (homogenous material). Non-uniqueness of the critical point by varying the detection threshold of cracking events is apparently due to finite size effects which introduce deviations from the self-similarity.     

Use of vibrational angioplasty for the treatment of chronic total coronary occlusions: Preliminary results

The aim of the study was to investigate the feasibility and clinical safety of vibrational angioplasty in the treatment of chronic total coronary occlusions and evaluate the clinical and angiographic factors that are predictive of the procedural success and complications of the procedure. Seventy-eight patients with chronic total occlusions (>3 months) resistant to conventional techniques were treated by vibrational angioplasty using a variety of conventional guidewires. Lesions were successfully crossed in 67 (85.9%) cases and antegrade flow was achieved in 59 (75.5%). Major complications (myocardial infarction and tamponade) occurred in two (2.5%) patients, but no fatalities ensued. Angiographically detectable dissections were seen in 23 (29.5%) patients but only resulted in vessel compromise and reclosure in 5 cases. Multiple stepwise logistic regression analysis identified the duration (<6 months, P = 0.008) and the length of the occlusion (<15 mm, P = 0.03) as independent predictors of final success and the age of the patient (<55 years, P = 0.006) as the only independent predictor of procedural complications. Vibrational angioplasty is a safe technique useful in the treatment of chronic coronary occlusive disease. Patients in whom the procedure is likely to prove most successful may be easily identified by clinical and angiographic features (duration and length of occlusion).Cathet. Cardiovasc. Intervent. 46:98–104, 1999. © 1999 Wiley-Liss, Inc.     

Electrophysiological markers predicting impeding AV‐block during ablation of atrioventricular nodal reentry tachycardia

1 Background

Radiofrequency (RF) ablation of the slow pathway (SP) in atrioventricular nodal reentry tachycardia (AVNRT) is occasionally complicated with atrioventricular block (AVB) often predicted by junctional beats (JB) with loss of ventriculo‐atrial (VA) conduction.

2 Methods

We analyzed retrospectively 153 patients undergoing ablation of SP for typical AVNRT. Patients were divided into two age groups: 127 ≤ 70 years and 26 > 70 years. We analyzed the interval between the atrial electrogram in the His‐bundle position and the distal ablation catheter [A(H)‐A(RFd)] and between the distal ablation catheter and the proximal coronary sinus catheter [A(RFd)‐A(CS)] before RF applications with and without JB. We evaluated if these intervals can be used as predictors of JB incidence and also of JB with loss of VA conduction. We also assessed if age influences the risk of loss of VA conduction.

3 Results

The A(H)‐A(RFd) and A(RFd)‐A(CS) intervals were significantly shorter in RF applications causing JB than those without JB (33 ± 11 ms vs 39 ± 9 ms, P < 0.001, 14 ± 9 ms vs 20 ± 7 ms, P < 0.001, respectively). The A(H)‐A(RFd) and A(RFd)‐A(CS) intervals were also significantly shorter in RFs causing JB with VA block than those with VA conduction (29 ± 11 ms vs 35 ± 11 ms, P < 0.001, 8 ± 8 ms vs 17 ± 8 ms, P < 0.001, respectively). Patients > 70 years had shorter intervals (36 ± 11 ms vs 29 ± 8 ms, P  =  0.012, 17 ± 8 ms vs 13 ± 7 ms, P  =  0.027, respectively), while VA block was more common in this age group.

4 Conclusions

The A(H)‐A(RFd) and A(RFd)‐A(CS) intervals can be used as markers for predicting JB occurrence as well as impending AVB. JB with loss of VA conduction occur more often in older patients possibly due to a higher position of SP.     

The value of neurophysiological and MRI assessment in demyelinating optic neuritis (DON).

PURPOSE: To study, by neurophysiological means, the possible involvement of the retina, in demyelinating optic neuritis (DON). MATERIAL AND METHODS: Thirty-five patients fulfilling strict criteria of unilateral DON were investigated with a battery of neurophysiological tests and MRI within 3 weeks of the onset of their symptoms. Flash-ERG (F-ERG) in photopic conditions, Flash-VEPs and PR-VEPs were recorded. MRI of the brain and the optic nerve were performed. RESULTS: The amplitude of b-wave of F-ERG in photopic conditions was statistically significantly lower in the affected eye (p < 0.001) compared to normal controls, whereas in the unaffected eye, it was also statistically significantly lower than normal controls (p < 0.01). All patients had statistically significant prolongation of P100 latency in PR-VEPs of the affected eye (p < 0.001) in comparison to normal controls. The P100 wave of the unaffected eye was also delayed (p < 0.01). In MRI, Gd-DTPA enhancement was observed in 7 symptomatic nerves with only minimal enhancement of the optic nerve between optic chiasm and optic canal, whereas 11 patients were presented with intracranial associated plaques. Five of the above patients had optic nerve enhancement and diffused demyelinating findings simultaneously. CONCLUSION: These results are a neurophysiological indication of involvement of the retina in DON, probably of vascular origin.