Experimental model of occluded biliary metal stent recanalization using irreversible electroporation via a tubular catheter.

PURPOSE: To demonstrate the feasibility of irreversible electroporation (IRE) for treating biliary metal stent occlusion in an experimental liver model. METHODS AND MATERIALS: IRE was performed using an expandable tubular IRE-catheter placed in nitinol stents in the porcine liver. A 3-electrode IRE-catheter was connected to an IRE-generator and one hundred 100µs pulses of constant voltage (300, 650, 1000, and 1300 V) were applied. Stent occlusion was simulated by insertion of liver tissue both ex vivo (n = 94) and in vivo in 3 pigs (n = 14). Three scenarios of the relationship between the stent, electrodes, and inserted tissue (double contact, single contact, and stent mesh contact) were studied. Electric current was measured and resistance and power calculated. Pigs were sacrificed 72 h post-procedure. Harvested samples (14 experimental, 13 controls) underwent histopathological analysis. RESULTS: IRE application was feasible at 300 and 650 V for the single and double contact setup in both ex vivo and in vivo studies. Significant differences in calculated resistance between double contact and single contact settings were observed (ex-vivo p ˂ 0.0001, in-vivo p = 0.02; Mann-Whitney). A mild temperature increase of the surrounding liver parenchyma was noted with increasing voltage (0.9-5.9 °C for 300-1000 V). The extent of necrotic changes in experimental samples in vivo correlated with the measured electric current (r2 = 0.39, p = 0.01). No complications were observed during or after the in-vivo procedure. CONCLUSION: Endoluminal IRE using an expandable tubular catheter in simulated metal stent occlusion is feasible. The relationship of active catheter electrodes to stent ingrowth tissue can be estimated based on resistance values.

Multiple cutaneous and hepatic infantile hemangiomas having a successful response to propranolol as monotherapy at neonatal period.

Infantile hepatic hemangioma (IHH) is a common liver tumors of infancy with a higher incidence in females. Various treatments for infantile hepatic hemangioma such as systemic corticosteroids, interferon-alpha, vincristine and cyclophosphamide have been suggested, though no consensus exists about the first-choice treatment. Recent evidences suggest that propranolol, a nonselective ß-blocker, may be effective and safe as first-line therapy for infantile hepatic hemangioma. We report a case of female born at term with a weight of 2.450 g started to develop multiple cutaneous IHs at 10 days of age and presenting concomitant multiple cutaneous and hepatic infantile hemangiomas confirmed on magnetic resonance imaging. Propranolol, used as monotherapy, was started at 14 days of age at a dose of 2 mg/kg/day orally and maintained for 6 months. Patient was monitored in the hospital during first days of treatment with propranolol, and discharged after no side-effects were detected. Hepatic and cutaneous lesions had complete resolution in three months, although the fibro-fatty residuum of largest cutaneous nodule was still palpable at month 6. A further control after 6 months showed no recurrences. Our report case suggests that propranolol can be a safe and effective first-line therapy for neonates with concomitant multiple cutaneous and hepatic infantile hemangiomas.

Modulation of angiogenesis by topical application of leptin and high and low molecular heparin using the Japanese quail chorioallantoic membrane model.

Pathological angiogenesis characterized by uncontrollable vessel growth is an accompanying feature of many diseases. The avian embryo chorioallantoic membrane (CAM) is an excellent model for angiogenesis research. In our study we used a less common Japanese quail CAM model for the testing of angiogenic potential of leptin, high-molecular (heparin sodium) andlow-molecular (nadroparin calcium) heparins. Heparins play a significant role in vascular endothelial cell function, and they are able to modulate the activities of angiogenic growth factors. On embryonic day 7 leptin (5 µg per CAM), heparin sodium (75 IU per CAM) and nadroparin calcium (47.5 IU per CAM) in 500 µl PBS were applied on the CAM surface. After 24 h the fractal dimension (Df) of the vasculature was evaluated. Samples from each group were histologically analyzed and VEGF-A and Quek1 expression were detected by qPCR. Df was significantly increased in the leptin group. A moderate stimulatory effect of heparin sodium and an inhibitory effect of nadroparin calcium were observed. Both leptin and heparin sodium caused a noticeable increase in the CAM thickness compared to the control and nadroparin calcium groups. We observed an increased number of blood vessels and accumulation of fibroblasts. There was no significant impact on gene expression of VEGF-A and Quek1 24 h after treatment, however, trends similar to the changes in Df and CAM thickness were present. The resulting effect of nadroparin administration on Quek1 levels was exactly the opposite to that of leptin (p < 0.05).

Polarization splay as the origin of modulation in the B1 and B7 smectic phases of bent-core molecules.

We report a generalized scenario for the formation of modulated smectic phases of bent-core molecules based on locally ferroelectric layering and spontaneous splay of the polarization. Twelve phases are proposed, distinguished by neighboring splay stripes with either syn- or antiorder of the polarization and undulation slope, in addition to layer continuity versus layer discontinuity at the intervening defects. We outline the experimental techniques necessary to differentiate among the phases and interpret previous results in the present context, using high resolution x-ray scattering diffraction and block and undulation models of the layer organization to distinguish among the three 2D lattice types which emerge.

Core-to-core dimers forming switchable mesophase.

We report structurally new type of dimers composed of bent-core molecules connected through their central cores by an alkylene spacer. Various self-assembling structures are discovered when prolonging the terminal alkyl chains in arms. Among diverse mesophases, the antiferroelectric type of switching under an applied electric field is observed.

Effect of Bacillus firmus on antibody formation after mucosal and parenteral immunization in mice.

Immunostimulatory properties of B. firmus, a nontoxic, nonpathogenic G + bacterium of external environment, were described previously. Antiinfectious and antitumor activity, macrophage activation and strong polyclonal stimulation of B lymphocytes were proved in human, mice and rats. The adjuvant effect of B. firmus on specific antibody response to ovalbumin in BALB/c mice is the topic of the present study. Against our expectation, B. firmus exerts more suppressive than stimulatory effect on specific antibody response. Formolized B. firmus decreased anti-ovalbumin response after subcutaneous immunization and only slightly increased serum antibodies after intraperitoneal immunization. After mucosal immunization, both oral and rectal, ovalbumin itself did not cause a significant systemic response but induced IgA anti-ovalbumin response in the intestine. B. firmus applied together with ovalbumin increased systemic serum response but absolutely eliminated intestinal response. The rectal route of antigen administration has been found less convenient because of less precise dosing of antigen in this mode of immunization.

Competition between the chiral smectic-C* and hexatic phases.

A theory of the phase transition from the smectic-C* to the hexatic phase based on the free energy with the two different Lifshitz terms is presented. Competition between the elastic energies of the tilt angle and of the hexatic order leads either to the single helicoidal structure, or to the double modulated solitonlike structure, and the transformation between both can occur. The bond order and the tilt angle suppress each other and at the transition to the low-temperature hexatic phase a decrease of the tilt angle and an anomaly in the helical pitch occur. Approaching the hexatic phase transition the dielectric response is contributed mainly by the bond-order phason or (and) the tilt angle phason. While the bond-order phason frequency decreases the tilt angle frequency increases in the hexatic phase. Both situations are treated being observed in experiment.

Molecular tilt near nanoparticles in the smectic-A phase of a de Vries liquid-crystalline compound.

We show how the inclusions of the nanoparticles or the clusters of nanoparticles in the liquid-crystalline smectic-A phase lead to layer deformations and may create a tilt in their vicinity, thus inducing locally a smectic-A-smectic-C transition. We have studied a freestanding film of "de Vries" compound, which exhibits the smectic-A-smectic-C transition without layer shrinkage, mixed with functionalized gold nanoparticles. The tilt induced by nanoparticle clusters, which decorate the edge dislocations, has been observed in the smectic-A phase. The tilt of liquid-crystal molecules near nanoparticles is a consequence of interaction of liquid-crystalline molecules with the surface of nanoparticles. The observed tilt may prove the concept of existence of a disordered tilt in the smectic-A phase of de Vries compounds. The tilt distribution near nanoparticles is discussed using both the smectic-A elasticity and local smectic-A-smectic-C transition.

Estrogenic and androgenic activity of PCBs, their chlorinated metabolites and other endocrine disruptors estimated with two in vitro yeast assays.

Investigations of environmental pollution by endocrine-disrupting chemicals are now in progress. Up to now, several in vitro bioassays have been developed for evaluation of the endocrine disruptive activity; however, there is still a lack of comparative studies of their sensitivity. In this work comparison of the estrogen screening assay based on beta-galactosidase expression and a bioluminescent estrogen screen revealed differences in the sensitivity and specificity of the two tests. With the beta-galactosidase screen a slight estrogen-like activity of Delor 103, a commercial mixture of PCB congeners, and a fungicide triclosan was measured whereas no activity was detected using the bioluminescent assay. A bioluminescent androgen test negated previously suggested androgenic potential of triclosan. Further, this work demonstrates the androgenic activity of Delor 103, with an EC(50) value of 2.29 x 10(-2)mg/L. On the other hand, chlorobenzoic acids (CBAs), representing potential PCB degradation metabolites, exhibited no androgenic activity but were slightly estrogenic. Their estrogenicity varied with their chemical structure, with 2,3-CBA, 2,3,6-CBA, 2,4,6-CBA and monochlorinated compounds exhibiting the highest activity. Thus the results indicated possible transitions of the hormonal activity of PCBs during bacterial degradation.

[Psychological disorders in Ethiopian university students--problems in transcultural psychiatry]. / Psychické poruchy u etiopských vysokoskoláku--príspevek k problematice transkulturální psychiatrie.

In the course of the ten-year period 1979-1988 the authors subjected to psychiatric examination or hospitalized 52 Ethiopian university students. The authors were concerned with the problem whether in the development and character of the psychopathological symptoms factors of the different cultural environment participated. University students sent to Czechoslovakia are a specific group which is not representative of the Ethiopian population. This may be the reason why the revealed symptoms did not differ markedly from conditions in the local population. This applies in particular to neurotic disorders, among which the neurasthenic syndrome predominated. In 14 hospitalized students schizophrenia was diagnosed 6 times, endogenous depression 6 times and neurotic symptoms due to maladaptation twice. The schizophrenic attacks presented classical symptoms, after their regression there was however, complete remission and thus the original diagnosis was somewhat doubtful.

Stimuli eliciting sexual arousal in males who offend adult women: an experimental study.

The sexually arousing effects of short film scenes showing a naked actress's seductive behavior were phalloplethysmographically measured in 14 sexual deviates. These were males who had offended adult women, predominantly exhibitionists. Controls were 14 normal men. Deviates responded positively to the scenes and differentiated strong and weak seduction scenes similarly to normals. Consequently, the question arises of why deviates avoid their victim's erotic cooperation and why they do not offend their regular sexual partners. Post hoc analysis of five scenes which elicited a strikingly higher response in deviates than in normals suggested that these scenes contained reduced seductive behavior but unrestrained presentation of the genitals. This finding further encourages the laboratory study of stimulus conditions for abnormal sexual arousal which occurs during the sexual offense.