Priscila Rossi de Batista

Toxic Effects of Mercury on the Cardiovascular and Central Nervous Systems

Environmental contamination has exposed humans to various metal agents, including mercury. This exposure is more common than expected, and the health consequences of such exposure remain unclear. For many years, mercury was used in a wide variety of human activities, and now, exposure to this metal from both natural and artificial sources is significantly increasing. Many studies show that high exposure to mercury induces changes in the central nervous system, potentially resulting in irritability, fatigue, behavioral changes, tremors, headaches, hearing and cognitive loss, dysarthria, incoordination, hallucinations, and death. In the cardiovascular system, mercury induces hypertension in humans and animals that has wide-ranging consequences, including alterations in endothelial function. The results described in this paper indicate that mercury exposure, even at low doses, affects endothelial and cardiovascular function. As a result, the reference values defining the limits for the absence of danger should be reduced.

Tributyltin contributes in reducing the vascular reactivity to phenylephrine in isolated aortic rings from female rats.

Organotin compounds such as tributyltin (TBT) are used as antifouling paints by shipping companies. TBT inhibits the aromatase responsible for the transformation of testosterone into estrogen. Our hypothesis is that TBT modulates the vascular reactivity of female rats. Female Wistar rats were treated daily (Control; CONT) or TBT (100 ng/kg) for 15 days. Rings from thoracic aortas were incubated with phenylephrine (PHE, 10(-10)-10(-4) M) in the presence and absence of endothelium, and in the presence of N(G)-Nitro-L-Arginine Methyl Ester (L-NAME), tetraethylammonium (TEA) and apocynin. TBT decreased plasma levels of estrogen and the vascular response to PHE. In the TBT group, the vascular reactivity was increased in the absence of endothelium, L-NAME and TEA. The decrease in PHE reactivity during incubation with apocynin was more evident in the TBT group. The sensitivity to acetylcholine (ACh) and sodium nitroprusside (SNP) was reduced in the TBT group. TBT increased collagen, reduced α1-smooth muscle actin. Female rats treated with TBT for 15 days showed morphology alteration of the aorta and decreased their vascular reactivity, probably due to mechanisms dependent on nitric oxide (NO) bioavailability, K(+) channels and an increase in oxidative stress.

Soybean oil increases SERCA2a expression and left ventricular contractility in rats without change in arterial blood pressure

BackgroundOur aim was to evaluate the effects of soybean oil treatment for 15 days on arterial and ventricular pressure, myocardial mechanics and proteins involved in calcium handling.MethodsWistar rats were divided in two groups receiving 100 μL of soybean oil (SB) or saline (CT) i.m. for 15 days. Ventricular performance was analyzed in male 12-weeks old Wistar rats by measuring left ventricle diastolic and systolic pressure in isolated perfused hearts according to the Langendorff technique. Protein expression was measured by Western blot analysis.ResultsSystolic and diastolic arterial pressures did not differ between CT and SB rats. However, heart rate was reduced in the SB group. In the perfused hearts, left ventricular isovolumetric systolic pressure was higher in the SB hearts. The inotropic response to extracellular Ca2+ and isoproterenol was higher in the soybean-treated animals than in the control group. Myosin ATPase and Na+-K+ATPase activities, the expression of sarcoplasmic reticulum calcium pump (SERCA2a) and sodium calcium exchanger (NCX) were increased in the SB group. Although the phosfolamban (PLB) expression did not change, its phosphorylation at Ser16 was reduced while the SERCA2a/PLB ratio was increased.ConclusionsIn summary, soybean treatment for 15 days in rats increases the left ventricular performance without affecting arterial blood pressure. These changes might be associated with an increase in the myosin ATPase activity and SERCA2a expression.

Fratura toracolombar do tipo explosão: o que o radiologista deve conhecer

Thoracolumbar burst fractures are defined as those fractures involving compromise of the anterior, middle and posterior vertebral columns. The treatment for such vertebral fractures still remains undefined, raising questions about the best form of intervention in these cases. Because of these doubts, imaging methods play a key role in the preoperative workup. However, several tests and measurements are performed by spine surgeons before deciding on the best approach to be adopted, with no standardization and neither consensus. The present review was aimed at standardizing and describing the main techniques and radiological findings on the basis of instability criteria adopted by surgeons in the assessment of thoracolumbar burst fractures, namely extent of height loss of the anterior wall of the fractured vertebra, level of spinal canal compromise by bone fragments and degree of widening of interspinous and interpedicular distance. It is the authors’ opinion that the standardization of the main measurements in the evaluation of thoracolumbar burst fractures by radiological methods will provide the information required for a better interpretation of tests results and consequently aiding in the decision making about the most appropriate treatment.

Low-dose ouabain administration increases Na+,K+-ATPase activity and reduces cardiac force development in rats

BACKGROUND Ouabain is a digitalis compound that inhibits the Na(+),K(+)-ATPase (NKA) activity inducing increment in cardiac force. However, this effect seems to be dose dependent. At low concentration, ouabain can induce an increase of NKA activity. METHODS We investigated the effects of ouabain administration (25 μg/kg/day) for 15 days on cardiac contractility and NKA activity. Blood pressure and left ventricular papillary muscle contraction from placebo and ouabain-treated rats for 15 (OUA15) days were evaluated. Isometric force, post-rest potentiation, positive inotropic intervention produced by isoproterenol, and tetanic tension were measured. The activity and protein expression levels of α1 and α2 isoforms of NKA, sodium calcium exchanger (NCX), sarcoplasmic reticulum calcium ATPase (SERCA2a) and phospholamban (PLB) were also measured. RESULTS Systolic and diastolic blood pressures increased after treatment with ouabain. However, isometric tension was reduced in the ouabain treated group. Post-rest potentiation, time parameters, inotropic interventions by isoproterenol and tetanic tension did not change. In the ouabain treated group, NKA activity was increased (Oua 406.16 ± 70.6 vs. CT 282.80 ± 80.5) while protein expression of the α1 isoform of NKA was reduced (Oua 0.97 ± 0.06 vs. CT 0.76 ± 0.05). No changes were observed in protein expression of α2 isoform of NKA, NCX, SERCA2a and PLB. Therefore, although 15-day ouabain treatment increases blood pressure (Oua: 116.4 ± 3 vs. CT: 99.9 ± 3), treatment also reduces isometric tension development (Oua: 0.34 ± 0.14 vs. CT: 0.56 ± 0.22). CONCLUSION We suggest that the effects induced by ouabain in the isolated cardiac muscle could be related at least in part, to changes in NKA activity.

Hypertensive effects of the iv administration of picomoles of ouabain

Ouabain, an endogenous digitalis compound, has been detected in nanomolar concentrations in the plasma of several mammals and is associated with the development of hypertension. In addition, plasma ouabain is increased in several hypertension models, and the acute or chronic administration of ouabain increases blood pressure in rodents. These results suggest a possible association between ouabain and the genesis or development and maintenance of arterial hypertension. One explanation for this association is that ouabain binds to the α-subunit of the Na(+) pump, inhibiting its activity. Inhibition of this pump increases intracellular Na(+), which reduces the activity of the sarcolemmal Na(+)/Ca(2+) exchanger and thereby reduces Ca(2+) extrusion. Consequently, intracellular Ca(2+) increases and is taken up by the sarcoplasmic reticulum, which, upon activation, releases more calcium and increases the vascular smooth muscle tone. In fact, acute treatment with ouabain enhances the vascular reactivity to vasopressor agents, increases the release of norepinephrine from the perivascular adrenergic nerve endings and promotes increases in the activity of endothelial angiotensin-converting enzyme and the local synthesis of angiotensin II in the tail vascular bed. Additionally, the hypertension induced by ouabain has been associated with central mechanisms that increase sympathetic tone, subsequent to the activation of the cerebral renin-angiotensin system. Thus, the association with peripheral mechanisms and central mechanisms, mainly involving the renin-angiotensin system, may contribute to the acute effects of ouabain-induced elevation of arterial blood pressure.

Treatment with high dose of atorvastatin reduces vascular injury in diabetic rats.

BACKGROUND Previous reports showed conflicting results regarding the treatment effects of statin on Diabetes mellitus (DM). We investigated how treatment with high dose of atorvastatin affects the impaired vascular function in diabetic rats. METHODS Atorvastatin (80mg/kg/day, oral gavage, 4 weeks) or its vehicle was administered to male control or streptozotocin (STZ)-induced diabetic rats. Aortic segments were used to investigate the vascular reactivity, protein expression of cyclooxygenase-2 (COX-2) and nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) 1 (NOX1) and superoxide anions levels. RESULTS Atorvastatin treatment did not affect glycemia levels. In diabetic rats, the vascular reactivity to phenylephrine increased compared with controls and the atorvastatin treatment reduced this response. Removal of the endothelium increased the response to phenylephrine in control rats, but not in the diabetic group. Atorvastatin increased the endothelial modulation in diabetic rats. L-NAME (100μM) increased the reactivity in all groups, but this effect was greater in atorvastatin-treated diabetic rats. Indomethacin (10μM) and NS398 (1μM) decreased the contractile response in diabetic rats and atorvastatin reversed these effects, without changing COX-2 expression. Apocynin (30μM) decreased the phenylephrine response in diabetic rats, which also showed increased NOX1 and superoxide anions; these effects were prevented by atorvastatin treatment. CONCLUSIONS The results suggest that treatment with high dose of atorvastatin, independent of glycemia, improves endothelial function in aortas from diabetic rats by reducing the constrictor prostanoids derived from COX-2 and by reducing the oxidative stress by NADPH oxidase, as well as a possible increasing of nitric oxide participation.

Síndrome de parsonage-turner: relato de caso em paciente HIV soropositivo

The Parsonage-Turner Syndrome is a rare disease that affects the muscles of the scapular girdle, leading to muscular atrophy and a large motor deficit. The etiology is unknown, but it is believed that infectious and autoimmune factors are involved. The diagnosis is made by exclusion, and the main differential diagnoses are cervical disc hernias, rotator cuff injuries and rheumatic diseases. During diagnostic research, we conducted laboratory tests, radiographs and MRI of the shoulder and cervical spine, with particular reference to electroneuromyography to help generate a definitive diagnosis. This case report is presented because it shows a disease that is rarely associated with HIV seropositivity and the importance of early diagnosis for better treatment of these patients.

Auxílio da tomografia computadorizada no planejamento pré-operatório de pacientes portadores de escoliose idiopática do adolescente

La escoliosis idiopatica en el adolescente (EIA) es una enfermedad diagnosticada en el inicio de la pubertad. Esta presenta una etiologia indefinida y es caracterizada por el desvio lateral de la columna vertebral por encima de los diez grados asociados a la rotacion del cuerpo vertebral. El uso de instrumentacion de tercera generacion produjo un mejor resultado en la correccion de la curva comparado con las tecnicas anteriores. Sin embargo, existen dificultades tecnicas en el momento del paso y de escoger los tornillos pediculares debido a la angulacion y al diametro de los pediculos vertebrales. A pesar de presentar ventajas, esta tecnica no esta libre de riesgos y complicaciones, necesitando de una mayor curva de aprendizaje por el medico cirujano, asi como tambien de un adecuado plan preoperatorio. Hasta el momento, no hay en la literatura un relato sobre la utilizacion de la tomografia computarizada en el auxilio quirurgico de los pacientes con escoliosis. Segun lo expuesto, proponemos, en el presente estudio, describir una tecnica para el plan preoperatorio con el auxilio de la tomografia computarizada para la fijacion de la columna en pacientes con escoliosis idiopatica del adolescente, especificando la angulacion y el diametro de los pediculos vertebrales, lo que podra auxiliar al medico cirujano en el momento de la fijacion.

Comparação do Índice de Torg obtido por meio de radiografia e ressonância magnética nos pacientes com mielopatia cervical espondilótica

OBJETIVO: La Mielopatia Cervical Espondilotica (MCE) es un trastorno relacionado con la degeneracion de la medula espinal, tipica del envejecimiento. En el estudio de imagen se puede obtener la medida del Indice de Torg para estimar la estenosis cervical. Nuestro objetivo es, por tanto, medir el indice de Torg mediante rayos-X y resonancia magnetica (RM), posibilitando verificar posibles discrepancias entre los metodos de medicion. METODOS: Se realiza la medicion del Indice de Torg en la radiografia y en la resonancia magnetica de la columna cervical, siendo obtenido mediante la determinacion de la relacion entre la superficie posterior del cuerpo vertebral y el punto mas cercano a la linea de la lamina correspondiente, dividido por el diametro sagital del cuerpo vertebral. RESULTADOS: Participo un total de pacientes 29, siendo 10 mujeres y 19 hombres, edad promedio de 48,1 ± 11 anos, peso 68,7 ± 5 Kg y altura de 1,68 ± 0,6 m. No hubo diferencias significativas entre el Indice de Torg calculado por la radiografia y el de la resonancia magnetica, siendo menores los indices observados en la RM (radiografia: 0,73 ± 0,17 vs RM: 0,48 ± 0,14, p <0,05). Sin embargo, ambas mediciones reflejan el mismo resultado: estenosis cervical absoluta (Indice de Torg <0,8). CONCLUSIONES: Nuestros resultados confirman los informes de otros autores quienes creen que el Indice de Torg medido por radiografia, como se recomienda, minimiza la estenosis real del canal cervical. En nuestro estudio se sugiere que la RM permite hacer una mejor estimativa del grado de estenosis del canal, aunque nuestros resultados, sobre el grado de estenosis cervical, fueron estadisticamente similares.OBJECTIVE: Cervical spondylotic myelopathy (SCM) is a dysfunction related to spinal cord degeneration typical of aging. In the imaging studies can achieve a measure of the Torg index to estimate cervical stenosis. We aim therefore to measure the Torg index in X-rays and Magnetic Resonance (MR), to investigate possible discrepancies between the methods of measurement. METHODS: The Torg Index was measured on radiographs and MR of the cervical spine, obtained by determining the relationship between the posterior surface of the vertebral body and the nearest point to the corresponding laminar line, divided by the sagittal diameter of vertebral body. RESULTS: A total 29 patients has participated, 10 women and 19 men, with mean age of 48.1 ± 11 years, weight 68.7 ± 5kg and height 1.68 ± 0.6m. There were significant differences between the Torg Index calculated by radiography and MR, and lower rates observed on MR (radiography: 0.73 ± 0.17 vs. RM: 0.48 ± 0.14, p <0.05). However, both measurements reflect the same result: absolute cervical stenosis (Torg index < 0.8). CONCLUSIONS: Our results confirm reports by other authors who believe that the Torg Index measured by radiography, as recommended, minimizes the actual cervical canal stenosis. Our study suggests that MRI allows better estimate of the degree of stenosis, although our results regarding the degree of cervical stenosis were statistically similar.