Viabilidade miocárdica na prática clínica / Assessing myocardial viability in clinical practice

Embora a avaliação da viabilidade miocárdica seja comum na prática do cardiologista, muitos médicos têm dúvidas a respeito dos resultados dos métodos diagnósticos. A medicina nuclear tem papel importante nos estudos de viabilidade, mas os laudos precisam ser interpretados num contexto clínico e fisiopatológico. Este artigo teve o objetivo de revisar a origem e a evolução do conceito da viabilidade miocárdica. São expostos os métodos diagnósticos com ênfase na medicina nuclear com uma explicação funcional sobre cada tipo de exame. A partir disso, são mostradas imagens como exemplos e é proposta uma maneira de atuar nesses casos baseada na clínica, na porcentagem de miocárdio acometido e na topografia das lesões coronarianas (proximais ou distais). (AU)

Although assessing myocardial viability is a common cardiology practice, many physicians question the results of diagnostic methods. Nuclear medicine plays an important role in viability studies, but the reports require interpretation in a clinical and pathophysiological context. this article was aimed at reviewing the origin and evolution of myocardial viability. Here we present diagnostic methods by emphasizing nuclear medicine and provide a functional explanation of each test type using example images. We also propose how to act in these cases based on clinic examination findings, the percentage of affected myocardium, and coronary lesion topography (proximal or distal).(AU)

Evaluación del contenido de selenio en hojas de hierbas nativas de uso tradicional en la alimentación del guatemalteco / Evaluation of selenium content in leaves of native herbs of traditional food use in Guatemala

El selenio (Se) es un elemento esencial para el ser humano que se encuentra en pequeñas cantidades en los suelos, pero se acumula en ciertas plantas, proporcionando beneficios como antioxidante, antiinflamatorio y quemopreventivo por la presencia de unas 25 selenoproteínas que participan en diversas acciones de bienestar, lactancia, desarrollo, reproducción y salud de la progenie. El objetivo de este estudio fue evaluar el contenido de Se en hojas de vegetales utilizados tradicionalmente en la alimentación guatemalteca. Se colectaron hojas de materiales cultivados para los mercados locales de nueve hierbas nativas (Amaranthus hybridus, Cnidoscolus aconitifolius, Crotalaria longirostrata, Dysphania ambrosioides, Lycianthes synanthera, Sechium edule, Solanum americanum, Solanum nigrescens y Solanum wendlandii) y dos introducidas de reconocido uso alimenticio (Moringa oleifera y Spinacia oleracea), se secaron en un horno de convección forzada para lograr una humedad < 10% y se digirieron 0.25 ± 0.02 g de hojas en una mezcla de ácido nítrico y ácido perclórico que se calentó hasta la digestión total de la materia. El Se fue determinado por el método de reflexión total de rayos X, utilizando un estándar interno de itrio (Y) el que se midió utilizando reflectores de cuarzo en un espectrómetro de reflexión total de rayos X. De todas las especies evaluadas, únicamente A. hybridus demostró cantidades cuantificables de Se. Se determinó que 100 g de materia vegetal seca de A. hybridus proporciona 0.355 mg de Se, por lo que su consumo semanal puede contribuir con el requerimiento de este micronutriente para un adulto.

Selenium (Se) is an essential element for the human being; it is in small amounts in the soil but it accumulates in certain plants, providing benefits as antioxidant, anti-inflammatory and chemopreventive, due to the presence of about 25 selenoproteins that participate in different welfare and development actions, lactation, reproduction and health of the progeny. This study aimed to assess Se content in leaves of nine native plants traditionally used in Guatemalan food (Amaranthus hybridus, Cnidoscolus aconitifolius, Crotalaria longirostrata, Dysphania ambrosioides, Lycianthes synanthera, Sechium edule, Solanum americanum, Solanum nigrescens and Solanum wendlandii) and two internationally uses herbs (Moringa oleifera, Spinacia oleracea). Se was determined by total reflection X-ray method. Plants were dried in a forced convection oven to constant weight, then were digested by weighing 0.25 ± 0.02 g of dry plant material with a mixture of nitric and perchloric acid, and warmed to achieve complete digestion. Using a yttrium (Y) internal standard were measured using quartz reflectors Spectrometer Total reflection X-ray. Of all native plant species tested, only A. hybridus there were measurable amounts of Se. It was determined that 100 g of dry plant material of A. hybridus provides 0.355 mg of Se, so its weekly consumption by an adult might contribute to satisfied the requirement of this microelement.

Distribution of rubidium, cesium, beryllium, strontium, and barium in blood and urine in general Chinese population / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the distribution of rubidium (Rb), cesium (Cs), beryllium (Be), strontium (Sr), and barium (Ba) in blood and urine in general Chinese population.</p><p><b>METHODS</b>A total of 18 120 subjects aged 6~60 years were enrolled from 24 regions in 8 provinces in Eastern, Central, and Western China from 2009 to 2010 based on the method of cluster random sampling. Questionnaire survey was conducted to collect the data on living environment and health status. Blood and urine samples were collected from these subjects, and the levels of Rb, Cs, Be, Sr, and Ba in these samples were determined by inductively coupled plasma mass spectrometry. The distribution of these elements in blood and urine in male or female subjects living in different regions was analyzed statistically.</p><p><b>RESULTS</b>In the general Chinese population, the concentration of Be in the whole blood was below the detection limit (0.06 μg/L); the geometric mean (GM) of Ba in the whole blood was below the detection limit (0.45 μg/L), with the 95th percentile (P95)of 1.37 μg/L; the GMs (95% CI)of Rb, Cs, and Sr in the whole blood were 2 374(2 357~2 392) μg/L, 2.01 (1.98~2.05) μg/L, and 23.5 (23.3~23.7) μg/L, respectively; in males and females, the GMs (95%CI)of blood Rb, Cs, and Sr were 2 506 (2 478~2 533) μg/L and 2 248 (2 227~2 270) μg/L, 1.88 (1.83~1.94) μg/L and 2.16 (2.11~2.20) μg/L, and 23.4 (23.1~23.7) μg/L and 23.6 (23.3~23.9) μg/L, respectively(P<0.01, P>0.05, and P>0.05). In the general Chinese population, the GM of urine Be was below the detection limit (0.06 μg/L), while the GMs (95%CI)of urine Rb, Cs, Sr, and Ba were 854 (836~873) μg/L, 3.65 (3.56~3.74) μg/L, 39.5 (38.4~40.6) μg/L, and 1.10 (1.07~1.12) μg/L, respectively; in males and females, the GMs (95%CI)of urine Rb, Cs, Sr, and Ba were 876 (849~904) μg/L and 832 (807~858) μg/L, 3.83 (3.70~3.96) μg/L and 3.47 (3.35~3.60) μg/L, 42.5 (40.9~44.2) μg/L and 36.6 (35.1~38.0) μg/L, and 1.15 (1.12~1.19) μg/L and 1.04 (1.01~1.07) μg/L, respectively (all P< 0.01). Correlation analyses showed that there were weak correlations between blood Rb and urine Rb (r=0.197)and between blood Sr and urine Sr (r=0.180), but a good correlation between blood Cs and urine Cs (r=0.487).</p><p><b>CONCLUSION</b>The levels of Rb, Cs, Be, Sr, and Ba in the general Chinese population are similar to those reported in other countries, and there is a significant difference in the concentration of each element among the populations living in different regions, as well as significant differences in blood Rb, urine Rb, urine Cs, urine Sr, and urine Ba between males and females.</p>

Evaluation of RbCl and CrCl3 as markers of Triatoma brasiliensis (Hemiptera: Reduviidae) nymphs: persistence and influence of Rb and Cr on triatomine biology

In order to mark Triatoma brasiliensis, the vector of Chagas disease in Brazil, two chemical compounds, rubidium chloride (RbCl) and chromium chloride (CrCl3), were tested. First, 199 N2-N5 nymphs were fed on blood with 0.025M RbCl. Rb marker positivity ranged from 2.5 percent (N3)-70 percent (N2), with a maximum persistence of 98 days. Second, 265 N2-N5 nymphs were fed on blood containing 0.0015M CrCl3. Cr marker positivity ranged up to 93 percent (N5), with a maximum persistence of 119 days. Finally, we blood fed 213 T. brasiliensis to investigate whether CrCl3 altered the biology of this insect. The developmental time of T. brasiliensis was unaltered, but the survival of the Cr-marked group was lower than that of the control group. Differences in the mean fecundity of the control (mean of 156.1) and experimental (mean of 135.6) groups were not statistically significant and 100 percent of the egg batches of females Cr-marked as nymphs were positive. In conclusion, CrCl3 is a useful tool for marking T. brasiliensis nymphs due to its high positivity and persistence.

application of unconventional PET tracers in nuclear medicine

The production and application of PET tracers has been a unique step in the progress of nuclear medicine in last two decades. The most important PET tracers include F-18, C-l 1 and N-13 radioisotopes and many nuclear medicine centers throughout the globe are using them. However some new tracers are under their way to the mass administration, currently being in the clinical trials or preliminary studies. Gallium-66 and 68 tracers such as Ga-DOTANOC and Ga-DOTANIC are currently being used in many neuroendocrine tumor studies in human in Europe and North America, and global application of these tracers remain to the cheaper and easier providence of [68]Ge[68]Ga generators. Copper tracers such as[61,62,64]Cu-ATSM and [61,62,64]Cu-PTSM are the most important unconventional tracers used in hypoxia and perfusion studies respectively using PET technology. Copper tracers can easily be produced using a medium cyclotron with simple chemistry. Many other interesting PET radioisotopes such as Tc-94m [HL. 52 min], 1-124 [HL. 100h], Y-86 [HL. 14.7] and rubidium tracers are being studied in some research centers in the world. This review article would describe the properties, mechanisms, production routes and problems of unconventional PET tracers with a look to the future of some important drug candidates

Efficiency of rubidium marking in Aedes albopictus (Diptera: Culicidae): preliminary evaluation on persistence of egg labeling, survival, and fecundity of marked female

Rubidium chloride (RbCl) has been used for the study of vector biology and behavior, although the efficacy of marking, egg production, and survivorship of marked females have been poorly studied. Four concentrations of RbCl were tested, among which 0.025 M was the best for marking Aedes albopictus: more than 80 percent of egg batches of females fed once with blood containing RbCl were marked; Rb-marked egg batches, interspersed with non marked ones were recovered until 61 days after a blood meal containing RbCl followed by non marked meals; RbCl was essentially detected in the abdomen of marked females, whose egg production and survivorship did not differ from non marked ones, at least in the three weeks following the Rb-marked blood meal.

Dispersal of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in an urban endemic dengue area in the State of Rio de Janeiro, Brazil

Experimental releases of female Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus were performed in August and September 1999, in an urban area of Nova Iguaçu, State of Rio de Janeiro, Brazil, to estimate their flight range in a circular area of 1,600 m where 1,472 ovitraps were set. Releases of 3,055 Ae. aegypti and 2,225 Ae. albopictus females, fed with rubidium (Rb)-marked blood and surgically prevented from subsequent blood-feeding, were separated by 11 days. Rb was detected in ovitrap-collected eggs by atomic emission spectrophotometry. Rb-marked eggs of both species were detected up to 800 m from the release point. Eggs of Ae. albopictus were more numerous and more heterogeneously distributed in the area than those of Ae. aegypti. Eggs positively marked for Rb were found at all borders of the study area, suggesting that egg laying also occurred beyond these limits. Results from this study suggest that females can fly at least 800 m in 6 days and, if infected, potentially spread virus rapidly

Na, K-ATPase: a molecular target for Leptospira interrogans endotoxin

On the basis of our report that a glycolipoprotein fraction (GLP) extracted from Leptospira interrogans contains a potent inhibitor of renal Na,K-ATPase, we proposed that GLP-induced inhibition of Na,K-ATPase might be the primary cellular defect in the physiopathology of leptospirosis. The present study was designed to test this hypothesis by determining whether or not 1) GLP inhibits all the isoforms of Na,K-ATPase which are expressed in the tissues affected by leptospirosis, 2) Na,K-ATPase from leptospirosis-resistant species, such as the rat, is sensitive to GLP, 3) GLP inhibits Na,K-ATPase from intact cells, and 4) GLP inhibits ouabain-sensitive H,K-ATPase. The results indicate that in the rabbit, a leptospirosis-sensitive species, GLP inhibits with similar efficiency (apparent IC5O: 120-220 mug protein GLP/ml) all isoforms of Na,K-ATPase known to be expressed in target tissues for the disease. Na,K-ATPase from rat kidney displays a sensitivity to GLP similar to that of the rabbit kidney enzyme (apparent IC50: 25-80 and 50-150 mug protein GLP/ml for rat and rabbit, respectively), indicating that resistance to the disease does not result from the resistance of Na,K-ATPase to GLP. GLP also reduces ouabain-sensitive rubidium uptake in rat thick ascending limbs (pmol mm-1 min-1 ñ SEM; control: 23.8 ñ 1.8; GLP, 88 mug protein/ml: 8.2 ñ 0.9), demonstrating that it is active in intact cells. Finally, GLP had no demonstrable effect on renal H,K-ATPase activity, even on the ouabain-sensitive form, indicating that the active principle of GLP is more specific for Na,K-ATPase than ouabain itself. Although the hypothesis remains to be demonstrated in vivo, the present findings are compatible with the putative role of GLP-induced inhibition of Na,K-ATPase as an initial mechanism in the physiopathology of leptospirosis.

Hipoxia y difunsión de 86 Rb en cerebro de rata / Hypoxia and diffusion of 86 Rh in rat brain

Se ha utilizado el Rb como análogo del ión K+ para determinar su constante de permeabilidad, (K, o PS) a nivel de la barrera hemato-encefálica, (BHE) de la rata. El método seguido es el de dilución de un indicador. La constante de permeabilidad para los animales control es de 0.92 ñ 0.02 M1. g-1.h-1, (corteza cerebral) y de 1.11 ñ 0.12 M1.g-1.h-1, (cerebelo de animales control). El valor K de los animales sometidos a hipoxia es de 0.24 ñ 0.01 M1.g-1.h-1, (corteza cerebral) y de 0.32 ñ 0.03 M1.g-1.h-1, (cerebelo)

Effect of sexual cycle on red cell membrane permeability as revealed by influx of Rubidium-86 and adenosinetriphosphatase in female rats.

Red cell membrane permeability, as revealed by influx of Rubidium-86 and ATPase activity, was studied in different phases of sexual cycle in female rats and no significant changes have been found.

Estudios hemodinámicos en la cardiopatía chagásica, con técnicas de radiotrazadores / Hemodynamic studies in the Chagasic cardiopathy, with technics of radiotracers

Trata estudios hemodinámicos en cardiopatía chagásica, iniciados hacia 1964, sobre la base de lautilización de técnicas no invasivas. En un comienzo, se intentó evaluar, en una serie de 90 pacientes y a través de la determinación radiocardiográfica, algunos parámetros derivados -indice cardíaco, volumen sistólico, y frecuencia cardíaca-; elaborándose una clasificación clínica-hemodinámica de la cardiopatía chagásica. En una segunda fase, se valoró la reserva cardíaca frente al esfuerzo; y, en una tercera fase, se estudió el comportamiento del clearence miocárdico de Rubidio 86 como parámetro de perfusión miocárdica o flujo miocárdico efectivo. Se muestran ejemplos de los efectos de drogas que esta metodologia permitió valorar en paciets chagásicos (efecto de isosorbide sublingual y efecto de Dipiridamol), y que se aplicó al estudio de pacientes chagásicos y no chagásicos marcapaseados crónicamente -239 marcapasos con un seguimiento máximo de 10 años-, estudiándose la performance ventricular del corazón marcapaseado crónicamente. Muestra imágenes de los bordes de isocuentas sistólica-diastólica, obtenidas en la computadora de la Cámara Gamma, iniciando así el estudio de las disquinesias, hipoquinesias o aquinesias de la miocardiopatía chagásica