Radiosensitizer effect of usnic acid on Biomphalaria glabrata embryos.

PURPOSE: Some phytochemicals have shown the potential of being radiomodifiers, especially phenolic compounds, such as lichenic secondary metabolites. To evaluate the phytochemical usnic acid as a radiomodifier, embryonic cells of molluscs have been used due to their ease of collection, high sensitivity to physical and chemical agents, well-known embryology and low cost for analysis. MATERIALS AND METHODS: This study aimed to assess the radiosensitizing action of usnic acid on Biomphalaria glabrata embryos. Samples were irradiated with 4 Gy of gamma rays from a 60Co source (dose rate 2.906 Gy/h). An acute toxicity test was performed using B. glabrata embryos in the blastula stage, in order to determine the toxicity of usnic acid and to establish the lethal Concentration for 50% (LC50). Subsequently, the radiomodifing capacity of usnic acid was estimated using assays with B. glabrata embryos. RESULTS: Irradiation increased the number of non-viable embryos compared to unirradiated controls. Additionally, it was observed that embryos exposed to a non-toxic concentration of usnic acid (0.6 µg/mL) before irradiation showed a further enhancement in non-viable embryos when compared with exposure to ionizing radiation alone. CONCLUSION: The results presented here indicate that usnic acid makes cells more sensitive to the damaging effects of radiation.

Estudio biométrico de la arterias femoral, poplítea y tibial posterior en relación a los implantes de stents / Biometric study of the femoral, popliteal and posterior tibial arteries in relation to the stents

Los aneurismas de la arteria poplítea son los más frecuentes entre los aneurismas periféricos, pudiendo ser tratados con stents a través de cirugía endovascular. Sin embargo, tales stents poseen el mismo diámetro en la parte proximal y distal, no siendo compatible con la anatomía vascular de ese segmento. El objetivo del presente estudio fue determinar la diferencia entre el diámetro del tercio distal de la arteria femoral y el diámetro de la arteria tibial posterior, además de obtener el diámetro de otras arterias del miembro inferior. Se utilizaron 28 cadáveres formolizados de individuos adultos, de ambos sexos, los que fueron disecados en la región correspondiente. Los diámetros registrados fueron los siguientes: en el tercio distal de la arteria femoral (inicio de la arteria poplítea), parte final de la arteria poplítea antes de su bifurcación en arterias tibial anterior y posterior, arterias tibial anterior y posterior (tronco tibiofibular). En el sexo masculino, desde el tercio distal de la arteria femoral hasta la arteria tibial posterior hubo una reducción del diámetro de 27,92% (p<0,0001). En el femenino, la reducción fue de 52,61% (p < que 0,0001). Al comparar el diámetro del tercio distal de la arteria femoral entre ambos sexos, se obtuvo una diferencia estadísticamente significativa (p < 0,0497), así como entre los diámetros de las arterias tibiales posteriores (p< 0,0142). Estos datos son de importancia clínica para los procedimientos de cirugía endovascular, pudiendo reducir las complicaciones en tales procedimientos. Las endoprotésis deberán adaptarse a estas diferencias de diámetro.

The popliteal artery aneurysms are the most common among peripheral aneurysms and can be treated with stents through endovascular surgery. However, these stents have the same diameter at the proximal and distal part , not being compatible with the vascular anatomy of that segment. The aim of this study was determine the difference between the diameter of the distal third of the femoral artery and the diameter of the posterior tibial artery, and to obtain the diameter of others arteries of the lower limb. We study 28 formalized cadavers of adult individuals of both sexes, which were dissected in the corresponding region. The following arterial diameters were recorded: the distal third of the femoral artery, distal part of the popliteal artery, anterior tibial artery and posterior tibial artery. In males from the distal third of the femoral artery to the posterior tibial artery there was a narrowing of 27.92% (p < 0.0001). In women , the reduction was 52.61 % (p<0.0001). By comparing the diameter of the distal third of the femoral artery between the sexes, a statistically significant difference was obtained (p<0.0497), as well as between the posterior tibial artery diameters (p < 0.0142). These data are of clinical importance for endovascular surgery procedures and may reduce complications in such procedures. Stents must adapt to these differences in diameter.

Importancia de la relación anatómica entre el nervio isquiático y el margen posterior del acetábulo en la luxación posterior de la cadera / Anatomic value of the sciatic nerve with the posterior margin of the acetabulum in posterior dislocation of the hip

La luxación posterior de la articulación de la cadera es un trauma que puede sufrir una buena parte de la población, donde se puede comprometer el nervio isquiático, produciendo serios problemas en la vida del individuo afectado. El conocimiento de la relación anatómica entre el nervio isquiático y el margen posterior del acetábulo propiciará um diagnóstico preciso y precoz de esta lesión. Con el objetivo de estudiar la relación topográfica del nervio isquiático con el margen posterior del acetábulo y entregar antecedentes anatómicos para las cirugías ortopédicas en caso de luxaciones posteriores de la cadera, se estudiaron 40 miembros inferiores formolizados, de cadáveres humanos, adultos y de ambos sexos, localizados en los laboratorios de anatomía topográfica de la Universidad Estadual de Ciencias de la Salud de Alagoas, Brasil. En 19 miembros inferiores (47,7 por ciento) el nervio isquiático pasó directamente sobre el margen posterior del acetábulo y en los 21 restantes (53,3 por ciento), el nervio estuvo distante del margen mencionado, distancia que varió de 6 a 49 mm. Los resultados obtenidos muestran la estrecha relación entre el nervio isquiático y el margen acetabular, lo que acrecienta la posibilidad de lesión del nervio em los casos de luxación posterior de la cadera...

The posterior dislocation of the hip joint is a trauma that can undergo a large part of the population, which may compromise the sciatic nerve, causing serious problems in the life of the affected individual. Knowledge of the anatomical relationship between the sciatic nerve and the posterior margin of the acetabulum will facilitate accurate diagnosis and early um this injury. In order to study the topographical relationship of the sciatic nerve with the posterior margin of the acetabulum and provide background for orthopedic anatomical in posterior dislocations of the hip were studied 40 lower limbs formolized human cadavers, adults of both sexes , located in the topographical anatomy laboratories of the Universidade Estadual de Ciencias da Saude, Alagoas, Brasil. In 19 limbs (47.7 percent) sciatic nerve passed directly over the posterior margin of the acetabulum and the remaining 21 (53.3 percent), the nerve passed distal to the acetabular margin, distance ranging from 6-49 mm. The results show the close relationship between the sciatic nerve and the acetabular margin, which increases the possibility of nerve injury in posterior dislocation of the hip...

A novel role of 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid as an activator of the phosphatase activity catalyzed by plasma membrane Ca2+-ATPase.

The hydrolysis of p-nitrophenyl phosphate catalyzed by the erythrocyte membrane Ca2+-ATPase is stimulated by low concentrations of the compound 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), a classic inhibitor of anion transport. Enhancement of the phosphatase activity varies from 2- to 6-fold, depending on the Ca2+ and calmodulin concentrations used. Maximum stimulation of the pNPPase activity in ghosts is reached at 4-5 microM DIDS. Under the same conditions, but with ATP rather than pNPP as the substrate, the Ca2+-ATPase activity is strongly inhibited. Activation of pNPP hydrolysis by DIDS is equally effective for both ghosts and purified enzyme, and therefore is independent of its effect as an anion transport inhibitor. Binding of the activator does not change the Ca2+ dependence of the pNPPase activity. Stimulation is partially additive to the activation of the pNPPase activity elicited by calmodulin and appears to involve a strong affinity binding or covalent binding to sulfhydryl groups of the enzyme, since activation is reversed by addition of dithiothreitol but not by washing. The degree of activation of pNPP hydrolysis is greater at alkaline pH values. DIDS decreases the apparent affinity of the enzyme for pNPP whether in the presence of Ca2+ alone or Ca2+ and calmodulin or in the absence of Ca2+ (with 5 microM DIDS the observed Km shifts from 4.8 +/- 1.4 to 10.1 +/- 2.6, from 3.8 +/- 0.4 to 7.0 +/- 0.8, and from 9.3 +/- 0.7 to 15.5 +/- 1.1 mM, respectively). However, the pNPPase rate is always increased (as above, from 3.6 +/- 0.6 to 11.2 +/- 1.7, from 4.4 +/- 0.5 to 11.4 +/- 0.9, and from 2.6 +/- 0.6 to 18.6 +/- 3.9 nmol mg-1 min-1, in the presence of Ca2+ alone or Ca2+ and calmodulin or in the absence of Ca2+, respectively). ATP inhibits the pNPPase activity in the absence of Ca2+, both in the presence and in the absence of DIDS. Therefore, kinetic evidence indicates that DIDS does more than shift the enzyme to the E2 conformation. We propose that the transition from E2 to E1 is decreased and a new enzyme conformer, denoted E2*, is accumulated in the presence of DIDS.

[The using of hollow bricks as a shelter for adaptation of wild rodents' colonies in captivity]. / Tijolos vazados como abrigo para adaptação de roedores silvestres em cativeiro.

Difficulties for adaptation of wild rodents' colonies in the laboratory may hamper experimental studies. We describe the use of a hollow brick inside cages, to provide shelter and reduce stress of the animals. It facilitates the cleaning of cages, since the animals stay inside the brick while they are transferred to a new cage. This method was applied in a trial for adaptation of Oryzomys nigripes in captivity. Despite transportation for more than 1500 km, mortality was zero in the group of 62 rodents and the colony expanded immediately. A hollow brick is a cheap and widespread available material for improving adaptation of wild rodents to captivity.

Tijolos vazados como abrigo para adaptação de roedores silvestres em cativeiro / The using of hollow bricks as a shelter for adaptation of wild rodents' colonies in captivity

Difficulties for adaptation of wild rodents' colonies in the laboratory may hamper experimental studies. We describe the use of a hollow brick inside cages, to provide shelter and reduce stress of the animals. It facilitates the cleaning of cages, since the animals stay inside the brick while they are transferred to a new cage. This method was applied in a trial for adaptation of Oryzomys nigripes in captivity. Despite transportation for more than 1500 km, mortality was zero in the group of 62 rodents and the colony expanded immediately. A hollow brick is a cheap and widespread available material for improving adaptation of wild rodents to captivity.

Dificuldade para o estabelecimento de colônias de roedores silvestres no laboratório podem impedir realização de estudos experimentais. Descrevemos o emprego de tijolos vazados dentro das gaiolas, com objetivo de proporcionar abrigo e reduzir o estresse dos animais. Isto facilita a limpeza das gaiolas e outros procedimentos, já que os animais permanecem espontaneamente dentro do tijolo, enquanto são transferidos para uma nova gaiola. Este método foi empregado em uma tentativa de adaptação de Oryzomys nigripes em cativeiro. Apesar do transporte por mais de 1500km, mortalidade foi zero no grupo de 62 roedores e a colônia expandiu-se imediatamente. O tijolo vazado é um material barato, facilmente disponível e contribui para a adaptação de roedores silvestres em cativeiro.

Evidences against a significant role of Mus musculus as natural host for Angiostrongylus costaricensis.

Wild rodents have been described as the most important hosts for Angiostrongylus costaricensis in Central America and southern Brazil. Sinantropic rodents apparently do not play a significant role as natural hosts. A search for natural infection failed to document worms in 14 mice captured in the house of a patient with diagnosis of abdominal angiostrongylosis and experimental infection of a "wild" Mus musculus strain and groups of albino swiss mice were carried out. Mortality was not significantly different and varied from 42% to 80% for Swiss mice and from 26% to 80% for "wild" mice. The high mortality of a "wild" M. musculus infected with A. costaricensis was very similar to what is observed with most laboratory mice strains. These data may be taken as indications that M. musculus is not a well adapted host for A. costaricensis, although susceptibility was apparently higher with "wild" populations of M. musculus as compared to Swiss strain.

Two simultaneous binding sites for nucleotide analogs are kinetically distinguishable on the sarcoplasmic reticulum Ca(2+)-ATPase.

Erythrosin B and eosin Y stimulate p-nitrophenyl phosphate hydrolysis by purified sarcoplasmic reticulum Ca(2+)-ATPase by nearly 2-3 fold in the presence of Ca(2+). This stimulation is not due to the change on the apparent affinity for substrate but is indeed due to acceleration of the turnover rate of the enzyme. Stimulation reaches a maximum at approximately 5 microM erythrosin or 20 microM eosin and is strictly dependent on the presence of Ca(2+) in reaction media, while higher concentrations of dye progressively inhibit phosphatase activity. Labeling with fluorescein isothiocyanate (FITC) largely shifts the Km for p-nitrophenyl phosphate (pNPP) and completely abolishes the stimulation of phosphatase activity induced by erythrosin in the presence of Ca(2+), apparently by FITC impairing dye binding to an activator site and allowing only manifestation of an inhibitory binding site. In the absence of Ca(2+), both erythrosin and eosin inhibit pNPP hyrolysis with Ic50 values 3-4 fold higher than the maximally stimulatory enzyme with FITC, which by its turn does not affect pNPPase activity in absence of Ca(2+). It is suggested that stimulation and inhibition of phosphatase activity are related to two simultaneous and physically different nucleotide analog binding sites.