Respuesta del tejido periapical de la rata a la sobreobturaci¨®n intencional de conos de resilon y conos de gutapercha recubiertos con resina / Periapical tissue response to intentional overextension of resilon and resin-coated gutta-percha cones: a preliminary study in rats

Objetivos. La sobreobturaci¨®n accidental o inadvertida con conos de gutapercha ocurre con cierta frecuencia en endodoncia cl¨ªnica. El prop¨®sito deeste estudio fue analizar la respuesta de los tejidos periapicales de la rata a sobreobturaciones intencionalesde conos de Resilon o conos de gutapercha recubiertos con resina. Material y m¨¦todos. Se obtuvo el acceso al conducto distal de los primeros molares inferiores (izquierdoy derecho) de 16 ratas macho Wistar con un peso de ¡À 250 g. Los conductos fueron preparados y sobreobturados con los materiales problema hasta una medida estandarizada de ¡À1 mm m¨¢s all¨¢ del ¨¢pice mediante el empleo de un localizador apical electr¨®nico. Las mand¨ªbulas fueron disecadas, fijadas en formol-buffer al 10 por ciento y descalcificadas. Los molares y los tejidos circundantes se prepararonpara su estudio histol¨®gico de rutina y se obtuvieron cortes seriados de aproximadamente 7 ¦Ìm de espesor de la ra¨ªz distal, los que fueron coloreadoscon hematoxilina y eosina. Los datos se categorizaron de acuerdo con par¨¢metros previamente establecidos y se analizaron mediante los tests deFisher, Kruskal-Wallis y el de comparaci¨®n m¨²ltiple de Dunn.Resultados. Luego de 30 d¨ªas la reacci¨®n a los materiales problema demostraron una respuesta inflamatoria moderada a severa. Estas reacciones disminuyeron significativamente (p<0.05) a los 90d¨ªas. En este lapso se observ¨® una reparaci¨®n progresiva de los tejidos periapicales circundada por un activo desarrollo de nuevas trab¨¦culas ¨®seas deapariencia normal. Conclusiones. Al finalizar la experiencia la reacci¨®n fue similar para ambos materiales, los que fueron bien tolerados por los tejidos periapicales, sin interferir con el proceso reparativo.

Respuesta del tejido periapical de la rata a la sobreobturaci¿«n intencional de conos de resilon y conos de gutapercha recubiertos con resina / Periapical tissue response to intentional overextension of resilon and resin-coated gutta-percha cones: a preliminary study in rats

Objetivos. La sobreobturaci¿«n accidental o inadvertida con conos de gutapercha ocurre con cierta frecuencia en endodoncia cl¿¬nica. El prop¿«sito deeste estudio fue analizar la respuesta de los tejidos periapicales de la rata a sobreobturaciones intencionalesde conos de Resilon o conos de gutapercha recubiertos con resina. Material y m¿ªtodos. Se obtuvo el acceso al conducto distal de los primeros molares inferiores (izquierdoy derecho) de 16 ratas macho Wistar con un peso de í? 250 g. Los conductos fueron preparados y sobreobturados con los materiales problema hasta una medida estandarizada de í?1 mm m¿ós all¿ó del ¿ópice mediante el empleo de un localizador apical electr¿«nico. Las mand¿¬bulas fueron disecadas, fijadas en formol-buffer al 10 por ciento y descalcificadas. Los molares y los tejidos circundantes se prepararonpara su estudio histol¿«gico de rutina y se obtuvieron cortes seriados de aproximadamente 7 ªÌm de espesor de la ra¿¬z distal, los que fueron coloreadoscon hematoxilina y eosina. Los datos se categorizaron de acuerdo con par¿ómetros previamente establecidos y se analizaron mediante los tests deFisher, Kruskal-Wallis y el de comparaci¿«n m¿²ltiple de Dunn.Resultados. Luego de 30 d¿¬as la reacci¿«n a los materiales problema demostraron una respuesta inflamatoria moderada a severa. Estas reacciones disminuyeron significativamente (p<0.05) a los 90d¿¬as. En este lapso se observ¿« una reparaci¿«n progresiva de los tejidos periapicales circundada por un activo desarrollo de nuevas trab¿ªculas ¿«seas deapariencia normal. Conclusiones. Al finalizar la experiencia la reacci¿«n fue similar para ambos materiales, los que fueron bien tolerados por los tejidos periapicales, sin interferir con el proceso reparativo.(AU)

Chronic cola drinking induces metabolic and cardiac alterations in rats.

AIM: To investigate the effects of chronic drinking of cola beverages on metabolic and echocardiographic parameters in rats. METHODS: Forty-eight male Wistar rats were divided in 3 groups and allowed to drink regular cola (C), diet cola (L), or tap water (W) ad libitum during 6 mo. After this period, 50% of the animals in each group were euthanized. The remaining rats drank tap water ad libitum for an additional 6 mo and were then sacrificed. Rat weight, food, and beverage consumption were measured regularly. Biochemical, echocardiographic and systolic blood pressure data were obtained at baseline, and at 6 mo (treatment) and 12 mo (washout). A complete histopathology study was performed after sacrifice. RESULTS: After 6 mo, C rats had increased body weight (+7%, P < 0.01), increased liquid consumption (+69%, P < 0.001), and decreased food intake (-31%, P < 0.001). C rats showed mild hyperglycemia and hypertriglyceridemia. Normoglycemia (+69%, P < 0.01) and sustained hypertriglyceridemia (+69%, P < 0.01) were observed in C after washout. Both cola beverages induced an increase in left ventricular diastolic diameter (C: +9%, L: +7%, P < 0.05 vs W) and volumes (diastolic C: +26%, L: +22%, P < 0.01 vs W; systolic C: +24%, L: +24%, P < 0.05 vs W) and reduction of relative posterior wall thickness (C: -8%, L: -10%, P < 0.05 vs W). Cardiac output tended to increase (C: +25%, P < 0.05 vs W; L: +17%, not significant vs W). Heart rate was not affected. Pathology findings were scarce, related to aging rather than treatment. CONCLUSION: This experimental model may prove useful to investigate the consequences of high consumption of soft drinks.

Histomorphometry of umbilical cord blood vessels in preeclampsia.

The authors hypothesized that preeclampsia may change the phenotype of umbilical cord vessels. Segments of umbilical cords were obtained from 29 pregnant women (20 healthy and 9 with preeclampsia), which were histomorphometrically assessed. Birth weight was 2928 ± 613 g for the control group vs 1749 ± 656 g for the preeclampsia group (P<.0001). A significantly shorter gestational period was noted in the preeclampsia group: 35 weeks vs 39 weeks in the healthy group. Measurements of the outer layer area (116.4 ± 55 µm(2) vs 56.5±25 µm(2) ; P=.0038), the inner layer area (63.1 ± 16 µm(2) vs 28.6±8 µm(2) ; P<.0001), the lumen area (8.4 ± 1 µm(2) vs 3.4±2 µm(2) ; P=.0003), and the wall/lumen ratio (20.3 ± 9 vs 3.1 ± 0.6; P<.0001) of arteries were significantly larger in the preeclampsia umbilical cords. Concerning veins, the wall/lumen ratio was higher in the preeclampsia group. In this study, the umbilical cord in preeclampsia showed significant changes in the structure of umbilical arteries, with increases in wall areas and wall/lumen ratios.

Subcutaneous connective tissue reaction to methacrylate resin-based and zinc oxide and eugenol sealers.

INTRODUCTION: An evaluation was made of the connective tissue reaction in rats after subcutaneous implantation of methacrylate resin-based sealers (EndoREZ [Ultradent Products, Inc, South Jordan, UT] with a polymerization accelerator and RealSeal [Sybron Dental Specialties, Orange, CA]) and Pulp Canal Sealer (Sybron Dental Specialties), a zinc oxide and eugenol-based sealer used as the control. METHODS: Silicone tubes containing the test materials were implanted in 24 Wistar rats. Solid silicone rods of the same size served as the negative controls. After 10, 30, and 90 days, the animals (n = 8 per period) were euthanized and the implants with surrounding tissues dissected and processed for routine histological evaluation. A four-category evaluation system was used to measure and record the microscopic observations according to the thickness of a fibrous capsule, the vascular changes, and the various types of inflammatory cells. RESULTS: Initially, a severe inflammatory reaction was observed of the soft tissues in direct contact with both EndoREZ/Accelerator and Real Seal. The severity decreased over time and was resolved at the end of the experiment. Pulp Canal Sealer showed a severe tissue reaction for all observation periods. The negative controls showed an initial mild to moderate inflammatory reaction. After 30 days, healthy fibrous connective tissue was observed, which increased over time. After 10 days, no statistically significant differences between the experimental groups were observed. After 90 days, EndoREZ and RealSeal were statistically significantly less toxic than Pulp Canal Sealer (p > 0.05). CONCLUSIONS: After 90 days, both methacrylate resin-based sealers were considered biologically acceptable when implanted in subcutaneous connective tissues of the rat. Pulp Canal Sealer remained toxic for the duration of the study.

Are kinking and coiling of carotid artery congenital or acquired?

Dolichoarteriopathies consist of tortuosity, kinking, or coiling of the extracranial carotid arteries. Some authors consider these alterations a consequence of atherosclerotic vessel remodeling, while others ascribe them to anatomical variations of embryological origin. The objective was to establish whether carotid dolichoarteriopathies belonged to a congenital origin or to acquired conditions. Color Doppler ultrasonography of neck vessels was performed in 885 participants, whose age ranged from 1-day-old infants to 90-year-old adults. Prevalence of kinking and coiling was evaluated, and it was related to the presence of cardiovascular risk factors. Prevalence of either kinking or coil of carotid arteries showed no increase with age, as it was comparable across all ages; furthermore, frequency of these alterations showed no relationship to cardiovascular risk factors nor to the presence of atheromatous plaques. These findings suggest that carotid dolichoarteriopathies are a result of alterations in embryological development rather than vascular remodeling secondary to aging and/or atherosclerosis.

Coronary intimal thickening in newborn babies and

We performed a morphological characterization of intimal thickenings in coronary arteries in the very early stages of life to obtain insights into initial coronary atherogenesis. We examined specimens from 67 infants who had died of noncardiac causes within their first year of life. Serially cut sections were stained with hematoxylin-eosin, Azan, Alcian blue, acetic orceine, and immunotypified for CD68, CD34, and alpha-smooth muscle (SM) actin. Substantial changes were detected in about 1 of 3 participants. Alterations ranged from focal areas with mild myointimal thickening to diffuse moderate thickening. In those lesions, smooth muscle cells (SMCs) showed loss of polarity, infiltrating the subendothelium, mostly with rupture of the internal elastic lamina and without neoangiogenesis. Morphometrically, in musculoelastic intimal thickenings, neointimal thickness averaged 58.3 +/- 17.8 microm, affecting 46% of the internal elastic membrane perimeter; lumen stenosis averaged 13.7% +/- 5.0%. These lesions can be present very early in life and SMCs seem to play an essential role.

Rat subcutaneous tissue response to modified Portland cement, a new mineral trioxide aggregate.

The purpose of this study was compare the biocompatibility of modified Portland cement (CPM) and mineral trioxide aggregate (MTA) in a subcutaneous rat model. Twenty-four male Wistar rats were used. Three silicon tubes were placed on the dorsal subcutaneous tissue of each animal: one tube contained MTA, one tube contained CPM and the other was an empty tube. The rats were sacrificed in 3 groups of 8 animals at 7, 14 and 30 postoperative days, respectively. Tissue samples were fixed in 10% buffered formalin, embedded in paraffin, and serial sections were cut and stained with hematoxylin and eosin, Masson Trichrome and Luna's stain. At day 7, the empty tubes displayed a mild inflammatory infiltrate. In the CPM group, an inflammatory infiltrate was observed with some eosinophils and immature connective tissue. The MTA group showed a similar infiltrate without eosinophils and presence of abundant necrotic tissue and numerous multinucleate foreign body giant cells. At day 14, the chronic infiltrate with eosinophils persisted when in contact with CPM. In the MTA group, necrosis and distant giant cells could still be seen. At day 30, all 3 groups showed mature fibrous collagenous tissue. These findings indicate a different response to the materials evaluated in this study. Although, MTA and CPM induced a chronic inflammatory infiltrate, necrosis and multinucleated foreign body giant cells predominated in the MTA group, while in the CPM group numerous eosinophils were seen at all the observational periods.

Carotid barochemoreceptor pathological findings regarding carotid plaque status and aging.

BACKGROUND: Carotid barochemoreceptor pathological lesions have been studied in animals, but few human necropsies have been performed. Therefore, data rely on case patients following surgery, radiotherapy and carotid endarterectomy. Almost no data are available regarding whether the effect of aging prevails over pathological conditions, despite the classic description that glomic fibrosis increases with age. OBJECTIVE: To morphometrically characterize the alterations of the carotid barochemoreceptors and their supplying arteries. METHODS: Patients (n=23) who had suffered and died from stroke, with and without complicated internal carotid atheromatosis, were divided by age (group 1: older than 80 years; group 2: 65 to 80 years; and group 3: younger than 65 years). Carotid segments were obtained at autopsy. The specimens were stained for light microscopy and immunohistochemistry. RESULTS: Carotid glomus presented from moderate-to-severe atrophy and fibrosis. A focal decrease in vascularization (CD34-positive) of the glomus (greater than 50%) was observed in areas of atrophy and fibrosis. Damaged nerve endings (S100 protein-positive) were observed at the media of the carotid sinus. Morphometric data showed no differences between groups for glomus area, number of type 1 and 2 cells, and the wall to lumen arteriole ratio. No statistical differences were demonstrated in the pathological findings of the carotid glomus when comparing complicated with noncomplicated plaques or age groups. CONCLUSION: Severe carotid chemoreceptor damage exists in patients who have died from stroke and suffered from carotid atheromatosis. These findings were independent from aging and plaque type. However, damage was correlated with a marked narrowing of the supplying arterioles as a consequence of hemodynamic and/or metabolic alterations (dyslipidemia, diabetes).

Rat subcutaneous tissue response to modified Portland Cement, a new mineral trioxide aggregate

The purpose of this study was compare the biocompatibility of modified Portland cement (CPM) and mineral trioxide aggregate (MTA) in a subcutaneous rat model. Twenty-four male Wistar rats were used. Three silicon tubes were placed on the dorsal subcutaneous tissue of each animal: one tube contained MTA, one tube contained CPM and the other was an empty tube. The rats were sacrificed in 3 groups of 8 animals at 7, 14 and 30 postoperative days, respectively. Tissue samples were fixed in 10 percent buffered formalin, embedded in paraffin, and serial sections were cut and stained with hematoxylin and eosin, Masson Trichrome and Luna's stain. At day 7, the empty tubes displayed a mild inflammatory infiltrate. In the CPM group, an inflammatory infiltrate was observed with some eosinophils and immature connective tissue. The MTA group showed a similar infiltrate without eosinophils and presence of abundant necrotic tissue and numerous multinucleate foreign body giant cells. At day 14, the chronic infiltrate with eosinophils persisted when in contact with CPM. In the MTA group, necrosis and distant giant cells could still be seen. At day 30, all 3 groups showed mature fibrous collagenous tissue. These findings indicate a different response to the materials evaluated in this study. Although, MTA and CPM induced a chronic inflammatory infiltrate, necrosis and multinucleated foreign body giant cells predominated in the MTA group, while in the CPM group numerous eosinophils were seen at all the observational periods.

O propósito deste estudo foi comparar a biocompatibilidade do cimento Portland modificado (CPM) com agregado de trióxido mineral (MTA) no subcutâneo de um modelo murino. Foram usados 24 ratos Wistar macho. No tecido subcutâneo dorsal de cada animal se colocaram 3 tubos de silicone. Um contendo MTA, outro CPM e o último vazio. Os animais foram sacrificados em 3 grupos de 8 aos 7, 14 e 30 dias. As amostras se fixaram em formol e se coloriram com hematoxilina - eosina, Masson e Luna. No dia 7 os tubos vazios mostraram uma leve infiltração de células inflamatórias. No grupo CPM, se observou um infiltrado inflamatório com alguns eosinófilos e tecido conectivo imaturo. O grupo MTA mostrou um infiltrado similar sem eosinófilos e abundante necrose de tecido e numerosas células gigantes multinucleadas do tipo corpo estranho. Ao dia 14, o infiltrado crônico com eosinófilos persistiu em contato com CPM. No grupo MTA, a necrose e células multinucleadas afastadas ainda se podiam observar. Ao dia 30, os 3 grupos mostraram tecido fibroso maduro. Estes resultados mostram uma resposta diferente aos materiais avaliados no presente estudo. Apesar do que MTA e CPM causaram um infiltrado crônico, no grupo MTA predominou a necrose e as células gigantes, enquanto isso, no grupo CPM se observaram grandes quantidades de eosinófilos.

Pulsed electromagnetic fields as adjuvant therapy in bone healing and peri-implant bone formation: an experimental study in rats.

The objective of this study was to determine whether short exposure to pulsed electromagnetic fields (PEMF) accelerates bone repair and peri-implant bone formation in a rat tibial model at different times. Sixty Wistar rats were employed. Sterile custom fabricated commercially pure cylinder threaded titanium implants were placed in the right tibial crest, and an osteotomy was performed in the left tibial crest of each animal. Thirty rats were treated with PEMF (72 mT 50Hz), twice a day in sessions of 30 minutes each, and 30 rats of the control group were sham-treated. Rats were sacrificed at 5, 10 and 20 days postsurgery (n = 10 per group). Tibias were fixed in formaldehyde and decalcified, embedded in paraffin, and stained with hematoxylin-eosin (half samples of left tibias), or they were included in methylmethacrylate, grinded and polished (right tibias and half samples of left tibias). Bone healing was evaluated by image analysis in terms of ossification area, and perimeter and diameter of the lesion. Peri-implant ossification was assessed in terms of ossification percentage. At day 10 the area of ossification index was higher in the PEMF group than in the control group (p = 0.012). At day 20 the osteotomies of the PEMF group were almost completely remodeled. The ossification percentage was higher in the PEMF group (p = 0.018). In conclusion, short daily electromagnetic stimulation appears to be a promising treatment for acceleration of both bone-healing and peri-implant bone formation.

Conflictos de interés: ¿a mí me importan? / Conflicts of interest: do I care?

Esta es una reflexión sobre la importancia de los conflictos de interés y su impacto en la práctica diaria. Se discuten algunos ejemplos de estudios clínicos sesgados y se propone la educación continua como solución para enfrentar el problema

¿Es el plasma rico en plaquetas (PRP) promotor de la cicatrización ósea en ratas diabéticas? / Effect of platelet rich plasma in diabetic rats

La ocurrencia de osteoporosis está documentada en diabetes tipo I. el objetivo de este trabajo fue evaluar el efecto del plasma rico en plaquetas (PRP) sobre la cicatrización ósea en ratas diabéticas... Como resultado el grupo control mostró ± 7,76 por ciento vs. 63,12 ± 15,34 porciento del grupo experimental de hueso neoformado (p= 0,0317). Como conclusión estos resultados sugieren un efecto favorecedor del PRP en la cicatrización ósea diabética, y potencialmente en otras fracturas de alto riesgo.

Lesiones ateroscleróticas tempranas en el síndrome de muerte súbita infantil / Early Atherosclerotic Lesions in Sudden Infant Death Syndrome

Objetivo El presente estudio se llevó a cabo con el propósito de caracterizar morfológicamente lesiones ateroscleróticas precoces en arterias coronarias de víctimas del "síndrome de muerte súbita infantil" (SMSI) para conocer los mecanismos aterogénicos. Material y métodos Se efectuó el examen de 52 víctimas de SMSI y de 16 casos controles fallecidos de causas conocidas. Las principales arterias coronarias se cortaron serialmente y se tiñeron con hematoxilina-eosina, Azán, azul alciano, orceína acética, CD68, CD34 y α-SM-actina y se realizó histomorfometría de las lesiones. Resultados Se encontraron lesiones preateroscleróticas en el 44,2% del grupo SMSI (23/52) y en sólo el 6,3% del grupo control (1/16) (p = 0,0062). Las células musculares lisas perdieron la polaridad, infiltrándose en el subendotelio, en gran parte de los casos con rotura de la membrana elástica interna (MEI). No se observó neoangiogénesis. En el grupo SMSI con engrosamiento musculoelástico intimal, el espesor neointimal fue de 58,3 ± 17,8 mm, el perímetro de la MEI afectado fue del 45,6%, el área de proliferación neointimal fue de 0,03 ± 0,01 mm² y el área luminal fue de 0,21 ± 0,1 mm² con 13,8% ± 5% de estenosis luminal. Conclusiones Las lesiones preateroscleróticas se desarrollan temprano en víctimas del SMSI y son significativamente más frecuentes que en los controles. Las células musculares lisas tienen un papel fundamental en su génesis.

Objective The aim of the present study was to assess the morphology of early atherosclerotic lesions in coronary arteries from sudden infant death syndrome (SIDS) victims in order to recognize atherogenic mechanisms. Material and Methods We examined 52 victims of SIDS and 16 controls with known causes of infant death. The principal coronary arteries were serially cut and stained with hematoxilin-eosin, Azan, Alcian blue, acetic orcein, CD68, CD34 and α-SM actin, with subsequent histomorphometric analysis of the lesions. Results Preatherosclerotic lesions were found in 44.2% in SIDS group (23/52) and only in 6.3% in controls (1/16) (p=0.0062). Smooth muscle cells lost polarity, infiltrating the subedothelium, with rupture of the internal elastic membrane (IEM) in most cases. Angiogenesis was not observed. When muscular and elastic intimal thickening was present in the SIDS group, the results were as follows: neointimal thickness, 58.3±17.8 mm; affected perimeter of the EIM, 45.6%; area of neointimal proliferation, 0.03±0.01 mm²; and luminal area, 0.21±0.1 mm² with a luminal stenosis of 13.8±5%. Conclusions Preatherosclerotic lesions develop early in SIDS victims, and they are significantly more frequent than in controls. Smooth muscle cells are fundamental in its genesis.

Perinatal and infant early atherosclerotic coronary lesions.

OBJECTIVE: Because the fetal origin of coronary artery lesions is controversial, early atherosclerotic coronary artery lesions in late fetal stillborns and infants, as well as the possible atherogenic role of maternal cigarette smoking, were studied. METHODS: Twenty-two fetal death and 36 sudden infant death syndrome victims were examined by autopsy. In 28 of 58 cases, the mothers were smokers. Serially cut sections of coronary arteries were stained for light microscopy and immunotypified for CD68, CD34, alpha-smooth muscle actin, proliferating cell nuclear antigen, c-fos and apoptosis. RESULTS: Multifocal coronary lesions were detected in 10 of 12 fetuses and in 15 of 16 infants whose mothers smoked. Arterial lesions in infants with nonsmoking mothers were observed in only five cases (two of 10 fetuses and three of 20 infants) (P<0.001). Alterations ranged from focal areas with mild myointimal thickening in prenatal life to early soft plaques in infants. Smooth muscle cells infiltrated into the subendothelium. These early lesions demonstrated c-fos gene activation in the smooth muscle cells of the media, and in some of these, positivity for apoptosis was observed, suggesting that c-fos overexpression may promote proliferation, as evidenced by proliferating cell nuclear antigen-positive cells. CONCLUSIONS: Early intimal alterations of the coronary arteries are detectable in the prenatal and infancy period, and may be significantly associated with maternal smoking.

Pulsed electromagnetic fields as adjuvant therapy in bone healing and peri-implant bone formation: an experimental study in rats

El objetivo del presente trabajo fue evaluar a diferentes tiemposen un modelo experimental en tibias de rata, el efecto de la exposición breve a campos electromagnéticos pulsantes(PEMF, del inglés Pulsed lectroMagnetic Fields) sobre la reparación y formación ósea peri-implantaria. Se utilizaron 60 ratas Wistar. En la cresta tibial derecha de cada animal se colocó un implante roscado de titanio comercialmentepuro y en la cresta tibial izquierda se efectuó una osteotomía. La mitad de los animales fueron tratados con PEMF (72 mT, 50Hz) dos veces por día (30 minutos por sesión), y la otra mitadconstituyó el grupo control. Las ratas se sacrificaron a los 5, 10 y 20 días postcirugía (n=10 por grupo). La mitad de las tibias derechas se descalcificaron,incluyeron en parafina y tiñeron con hemato xilina-eosina, mientras que al resto se las incluyó en metil-metacrilato y se realizaron cortes por desgaste. Se evaluó el área de osificación, el perímetro y el diámetro de las osteotomías mediante un analizadorde imágenes. Para evaluar la osificación peri-implante se obtuvo el porcentaje de osificación. Al día 10 el índice del área de osificación fue significativamentemayor en el grupo PEMF que en el control (190,6±13,6 vs. 147,9±6,3; p=0,012). Al día 20, las osteotomías del grupo PEMF estaban, en su mayor parte remodeladas. El porcentaje de osificación fue mayor en el grupo PEMF respecto al control (51,9±10,4 por ciento vs. 36±12.1 por ciento; p=0,018). La breve estimulación electromagnética pulsante diaria sería un tratamiento promisorio para facilitar la reparación ósea y peri-implantaria.

Relationship between oxidative stress, lipid peroxidation, and ultrastructural damage in patients with coronary artery disease undergoing cardioplegic arrest/reperfusion.

OBJECTIVE: In animal models, formation of oxidants during postischemic reperfusion may exert deleterious effects ("oxidative stress"). Cardioplegic arrest/reperfusion during cardiac surgery might similarly induce oxidative stress. However, the phenomenon has not been precisely characterized in patients, and therefore the role of antioxidant therapy at cardiac surgery is a matter of debate. Thus, we wanted to ascertain whether the relationship between oxidant formation and development of myocardial injury also translates to the situation of patients subjected to cardioplegic arrest. METHODS: In 24 patients undergoing coronary artery bypass, trans-cardiac blood samples and myocardial biopsies were taken before cardioplegic arrest and again following reperfusion. RESULTS: Cardiac glutathione release (marker of oxidant production) was negligible at baseline (0.02+/-0.04 micromol/L), but it increased 15 min into reperfusion (1.10+/-0.40 micromol/L; p<0.05); concomitantly, myocardial concentration of the antioxidant ubiquinol decreased from 144.5+/-52.0 to 97.6+/-82.0 nmol/g (p<0.05). Although these changes document cardiac exposure to oxidants, they were not accompanied by evidence of injury. Neither coronary sinus blood nor cardiac biopsies showed increased lipid peroxide concentrations. Furthermore, electron microscopy showed no major ultrastructural alterations. Finally, full recovery of left ventricular systolic and diastolic function was observed. CONCLUSIONS: Careful investigation reveals that while oxidant production does occur during cardiac surgery in patients with chronic ischemic heart disease, cardiac oxidative stress may not progress through membrane damage and irreversible injury.

Adriamycin-induced myocardial toxicity: new solutions for an old problem?

Adriamycin is a potent and broad-spectrum antineoplastic agent that plays a major role in cancer chemotherapy. Unfortunately, its use has been hampered by conventional toxicities and cardiotoxicity manifested by congestive cardiomyopathy. Adriamycin is particularly toxic to heart tissue and constitutes a major cause of morbidity and mortality due to its complex pathogenesis. In this review, the different forms of cardiotoxicity produced by adriamycin as well as the biochemical changes induced by this drug are summarized. Secondly, the current hypotheses proposed to explain adriamycin-induced myocardial damage (the iron and free-radical hypothesis, the metabolic hypothesis, the "unifying hypothesis" and apoptosis) and the attempts to reduce adriamycin-induced myocardial toxicity are discussed (e.g. dose limitation, close cardiac monitoring, alteration of dosage schedules, development of new anthracycline analogs, and the administration of protective agents and liposomal encapsulation). Finally, we summarized our own experimental and clinical experience in ameliorating and or preventing adriamycin-induced cardiotoxicity and the latest attempts to prevent and/or monitor cardiac function. According to this, a combination of usual doses of calcium antagonist drugs plus vitamins A and E seems advisable.