Efficacy of new active viscosupplements on the behavior of an experimental model of osteoarthritis. / Eficacia de nuevos viscosuplementos activos en el comportamiento de un modelo experimental de osteoartritis.

OBJECTIVE: To evaluate with an animal model of osteoarthritis (New Zealand rabbits) the effectiveness of treatment with active viscosupplements (hyaluronic acid loaded with nanoparticles (NPs) that encapsulate anti-inflammatory compounds or drugs. MATERIAL AND METHODS: Experimental study composed of 5 groups of rabbits in which section of the anterior cruciate ligament and resection of the internal meniscus were performed to trigger degenerative changes and use it as a model of osteoarthritis. The groups were divided into osteoarthrosis without treatment (I), treatment with commercial hyaluronic acid (HA) (II), treatment with HA with empty nanoparticles (III), treatment with HA with nanoparticles encapsulating dexamethasone (IV) and treatment with HA with nanoparticles that encapsulate curcumin (V). In groups II to V, the infiltration of the corresponding compound was carried out spaced one week apart. Macroscopic histological analysis was performed using a scale based on the Outerbridge classification for osteoarthritis. RESULTS: We observed that this osteoarthritis model is reproducible and degenerative changes similar to those found in humans are observed. The groups that were infiltrated with hyaluronic acid with curcumin-loaded nanoparticles (V), followed by the dexamethasone group (IV) presented macroscopically less fibrillation, exposure of subchondral bone and sclerosis (better score on the scale) than the control groups (I) (osteoarthritis without treatment), group (II) treated with commercial hyaluronic acid and hyaluronic acid with nanoparticles without drug (III). CONCLUSIONS: The use of active viscosupplements could have an additional effect to conventional hyaluronic acid treatment due to its antioxidant and anti-inflammatory effect. The most promising group was hyaluronic acid with nanoparticles that encapsulate curcumin and the second group was the one that encapsulates dexamethasone.

Randomized comparison of efficacy of cooled tip catheter ablation of atrial flutter: anatomic versus electrophysiological complete isthmus block.

There is a subset of patients with failed ablation of the cavotricuspid isthmus (CTI) using standard catheters and with 10% of the patients having recurrences. The purpose of this study was to compare the cooled and standard ablation with regard to acute successful electrophysiological achievement of bidirectional isthmus block and the subacute anatomic characteristics of the lesions. This randomized, experimental study compares the effects of ablation on the isthmus using a cooled catheter with those of a standard ablation catheter in 16 pigs. In 12 animals, CTI block was achieved after ablation (8/8 cooled and 4/8 standard). In two animals, it was not possible to achieve complete isthmus block and two had persistent slow conduction (all four using the standard catheter). After 1 week, the animals were slaughtered. The size of the lesion was greater with the irrigated tip catheters. Transmural lesions were found in 14 animals. A complete line of anatomic isthmus block was not documented after thefirst line in six animals, four with the standard and two with the cooled catheter. A conduction block was never present across gaps > or = 5 mm. In conclusion cooled catheters achieved a complete line of electrophysiological and anatomical block in a significantly higher percentage than the standard catheters.

[Evaluation of the anatomopathological characteristics and the safety of radiofrequency lesions at the atrial level with two different systems of irrigated tip catheters on an experimental level]. / Estudio de las características anatomopatológicas y la seguridad de las lesiones producidas en la aurícula con dos diferentes sistemas de catéteres de punta irrigada en un modelo experimental.

INTRODUCTION AND OBJECTIVES: We performed this study to evaluate the security and efficacy in the lesions produced on the atrial wall by different irrigated catheters in an experimental model. We evaluated the anatomopathologic characteristics of the lesions produced by two different systems of irrigated tip catheters, with opened or closed circuit. METHODS: This study was performed in 16 pigs applying 60 sec radiofrequency pulses with three different energy levels (15, 25 y 50 Watts). Two different systems of radiofrequency ablation irrigated catheters were used, opened and closed. We used 4 pigs in which we performed ablation with a standard catheter as a control group. Under fluoroscopic guidance, catheters were placed on the high and low right atrial lateral wall, where lesions were produced. After 7 days, animals were sacrificed for anatomopathological study. RESULTS: A total of 27 lesions were performed with irrigated catheters (11 closed circuit and 16 opened) and 6 with standard catheters in the control group. We did not find significant differences in the lesion characteristics between the two different systems of irrigated tip catheter used, nevertheless lesions performed with the closed system were slightly greater. Th lesions produced with irrigated catheters were always superior in the control group. Transmurality in the free atrial wall is frequent with both systems. We did not see any perforation in the atrial wall. CONCLUSIONS: We did not find significant differences in the size of the lesions produced with the two systems of irrigated catheters used. These data from an experimental model can provide useful information for atrial tachycardia radiofrequency ablation procedures in humans.

[Macroscopic and microscopic study of the right coronary artery after radiofrequency catheter ablation of cavotricuspid isthmus in an experimental model]. / Estudio macro y microscópico de la arteria coronaria derecha tras ablación con catéter y radiofrecuencia del istmo cavotricuspídeo en un modelo experimental.

INTRODUCTION AND OBJECTIVES: The right coronary artery (RCA) is found in the AV groove, just below the ablation target of atrial flutter, the cavotricuspid isthmus (ICT). After radiofrequency (RF) ablation with standard catheters, there have been no reports of complications, but it may not be successful in 10% of the cases. However, the use of irrigated tip catheters, which create deeper lesions, might potentially damage the coronary tree. METHODS: We analyzed the effects of ICT RF ablation on the coronary tree, with macroscopic and microscopic anatomopathological study. Ablation on ICT was performed using an irrigated tip catheter in 16 pigs and was randomly compared with a standard ablation catheter. There were no clinical problems, modifications of ST or new arrhythmias during the ablation. The heart was extracted at 1 week. RESULTS: The macroscopic study demonstrated that the right coronary artery was preserved, along the ICT, surrounded by the epicardial fat. The microscopic study showed an inflammatory reaction in the epicardial fat that reached the adventitia of the coronary artery, but never produced necrosis in 14 cases. The muscular wall of the artery had signs of focal inflammation without endothelium involvement in 2 cases. However, we found a subepicardial vein completely damaged by the radiofrequency. CONCLUSIONS: Although the right coronary artery is located just below the isthmus, no necrosis was observed in any case. However, there was an inflammatory reaction that focally reached the muscular wall. The veins may be damaged in RF ablation, perhaps due to the different blood flow of each vessel.

[Anatomopathological and biochemical correlation of lesions produced by standard and irrigated 4 mm radiofrequency catheters]. / Correlación anatomopatológica y bioquímica de las lesiones producidas por la radiofrecuencia con catéteres estándar e irrigados de 4 mm.

INTRODUCTION AND OBJECTIVES: The influence on the size of radiofrequency lesions by cooling of the tip of the electrode remains unclear. Moreover, the possible effects of two different cooling systems, closed and open, have not been well differentiated. We designed this study to compare both systems of irrigated-tip catheters and the lesions produced with standard 4 mm catheters and also to evaluate the pathological and biochemical marker release correlation (cardiac troponin I) in an experimental model. METHODS: The study was performed in 20 pigs. Applying between 1-8 radiofrequency pulses, at a power of 15, 25 or 50 watts, for 15-60 seconds to each animal. After 7 days, the pigs were sacrificed for anatomopathological study. RESULTS: A total of 54 lesions were produced, 25 with standard catheters and 29 with irrigated catheters. The mean volume of the lesions produced with standard catheters was 146 +/- 110 microl and with irrigated-tip catheters 856 +/- 864 microl (p < 0.001). Peak values of cardiac troponin I were also higher for irrigated catheters (18 +/- 15 ng/ml) than for standard (6.5 +/- 3 ng/ml). The correlation between the size of the lesion and the levels of cardiac troponin I were 0.86 and 0.79 with the standard and irrigated-tip catheters, respectively. The incidence of cratering was higher with standard catheters (60%) than with irrigated (27%). CONCLUSIONS: The lesions produced with an irrigated catheter are greater than those observed with standard catheters. The mean peak value of postablation cardiac troponin demonstrate a good correlation with the real size of the necrosis.

[Prolactinemia in children anesthetized with propofol]. / Prolactinemia en niños anestesiados con propofol.

OBJECTIVES: To assess the relation between plasma levels of prolactin and spontaneous movements in children anesthetized with propofol and to compare the prolactin endocrine response for 2 different techniques of anesthetic maintenance. PATIENTS AND METHOD: This was a prospective study of 35 ASA I children between 4 and 11 years of age, with no history of epilepsy or febrile convulsions, who underwent herniorrhaphy or orchidopexy. The patients were not premedicated. Before induction they received 0.02 mg/kg atropine and 2.5 micrograms/kg i.v.; induction was with 4 mg/kg propofol and 0.5 mg/kg atracurium. For maintenance the sample was randomly divided into 2 groups. Group A (n = 18) received 10 mg/kg/h propofol and 40% O2/air. Group B (n = 17) received 1-0.7% isoflurane and 40% N2O/O2. We measured plasma levels of prolactin before induction (baseline prolactin) and after extubation (postoperative prolactin). We also assessed pain upon injection of propofol by observing and recording spontaneous movement. RESULTS: The number of children who remained in the study was 24, with 14 in group A and 10 in group B. We observed a significant increase (p < 0.05) of postoperative prolactin in children with spontaneous movement (15.3 +/- 7.5 vs. 87.1 +/- 42.9 ng/ml) as well as in those with no movement (23.8 +/- 15.9 vs. 82.4 +/- 29.7 ng/ml). There were no significant differences between baseline prolactin (20.9 +/- 16.9 vs. 21.8 +/- 10.8 ng/ml) and postoperative levels (90 +/- 35.4 vs. 75 +/- 29 ng/ml) related to technique. CONCLUSIONS: Increase in prolactin is unrelated to spontaneous movements, which are attributable to low induction dose. Differences in prolactin plasma levels are not related to anesthetic technique.

[Iodine overload in newborn infants caused by the use of PVP-iodine for perineal preparation of the mother in vaginal delivery]. / Sobrecarga iodada al recién nacido por utilizar PVP-iodada para la preparación perineal materna en el parto vaginal.

The high incidence of transient thyroid dysfunction in newborns from our hospital (0.6%), led us to investigate whether povidone perineal prep. during delivery and daily postpartum antisepsis, induced iodine overload in the newborn, and whether breast milk was the vehiccle. In a controlled randomized trial we used either povidone-iodine or clorhexidine in 36 mothers, and we investigated in them and in their newborns iodine levels and thyroid function. Iodine levels in cord blood, maternal urine and newborn urine were significantly higher in povidone treated group (p less than 0.001) up to the 4th postpartum day. These levels were also significantly higher in breast fed than in formula-fed babies within the group of povidone-iodine-treated mothers. Maternal prepartum urine iodine, and thyroid function in mothers and newborns were not significantly different in both groups.