Evaluación de la capacidad neutralizante de extractos de plantas de uso popular en Guatemala como antídotos para el envenenamiento por la mordedura de Bothrops asper / Neutralizing activities of ethanolic extracts of six plants traditionally used in Guatemala as antidotes for the envenomation caused by the snake Bothrops asper

Se determinó la capacidad de los extractos de seis plantas de uso etnomédico (Acacia hindsii, Aristolochia maxima, Cissampelos pareira, Hamelia patens, Piper peltatum y Sansevieria hyacinthoides) para neutralizar los efectos proteolítico y fosfolipasa A2 (PLA2) del veneno de Bothrops asper, la principal especie causante de envenenamiento en el país. Estos efectos, indicadores de la capacidad miotóxica, hemorrágica e inflamatoria del veneno, se evaluaron en ensayos controlados in vitro. Las plantas fueroncolectadas, secadas y extraídas por percolación con etanol. Los resultados demuestran que ninguno de los extractos posee actividad PLA2 o proteo-lítica intrínseca a las dosis estudiadas. Se determinó que tres de los extractos neutralizaron pobremente (< 50%) los efectos estudiados: S. hyacinthoides neutralizó 13.90 ± 6.41% del efecto PLA2 y P. peltatum y C. pareira el 32.98 ± 5.51% y 24.52 ± 7.45%, respectivamente, del efecto proteolítico. Por ello, ningún extracto se evaluó en pruebas de neutralización de la letalidad en ratones. Se concluye que no es recomendable el uso aislado de estas plantas en el tratamiento del envenenamiento por mordedura de B. asper, aunque posiblemente las que demostraron alguna actividad puedan resultar potenciadas al usarse en combinación con otras plantas, como se hace en las recetas tradicionales. Dada la complejidad de los componentes del veneno y sus efectos fisiopatológicos, falta investigar la capacidad de las plantas estudiadas para neutralizar las coagulopatías, edema y miotoxicidad producidas durante el envenenamiento.

Many plants are reported to be used in Guatemalan traditional medicine as antidotes against various effects of the snakebite; however, very few attempts have been made to evaluate their neutralizing capacity in controlled experiments. Six plants (Acacia hindsii, Cissampelos pareira; Hamelia patens, Piper peltatum, Sansevieria hyacinthoides and Aristolochia maxima) were evaluated in vitro for their ability to neutralize phospholipase A2 (PLA2) and proteolytic effects of the venom of Bothrops asper, the snake responsible for approximately half of the snakebite envenomations in Central America. These effects are indicatives of the ability of B. asper venom to produce myotoxicity, hemorrhage and inflammation. Plants were collected, dried and extracted by maceration with ethanol. After pre-incubation of several amounts of each extract with a challenge dose of venom, S. hyacinthoides demonstrated a low neutralizing capacity (< DE 50) of the PLA2 effect (13.90 ± 6.41%); C. pareira (32.98 ± 5.51%) and P. peltatum (24.52 ± 7.45%) neutralized less than 50% of the proteolytic effect. The results suggest that neither of the tested plants should be used individually to treat the main effects of B. asperenvenomation. However, the three low-active extracts might be potentiated when used in mixtures composed of several plants, as prepared by traditional healers. Given the complexity of the venom components and the multiple pathologic effects produced by B. asper envenomation, more tests are required to fully investigate the ability of this plants to neutralize the coagulant, fibrin(ogen)olytic, edematizing and myotoxic effects of the venom.

Ética sobre el envenenamiento ofídico en el paisaje agrario de Guatemala / Ethics of snakebite envenoming in agrarian landscapes of Guatemala

El envenenamiento ofídico es una enfermedad accidental, no infecciosa o contagiosa, causada por los efectos de los venenos de serpientes de las familias Viperidae, Elapidae y Colubridae. Esta enfermedad representa un problema de salud pública a nivel mundial, afectando principalmente a los trabajadores agrícolas. A pesar de derivarse de una relación ecológica antagónica natural entre humanos y serpientes el accidente ofídico es moralmente juzgado como algo malo. En tal sentido, el examen de esta relación supone un componente ético. En el presente ensayo se discute cuál es el significado moral de las serpientes venenosas bajo las perspectivas antropocentrista y biocentrista. Se abordan los temas de riesgo ocupacional y vulnerabilidad del trabajador agrícola a la enfermedad, se elabora sobre las causas de la desatención de esta enfermedad y se reflexiona sobre cuál es la responsabilidad ética del estado, del empresario y del consumidor, en la existencia de ésta enfermedad. Finalmente se discute el papel de la epidemiología social, como una herramienta generadora de información útil para la comprensión de la realidad multidimensional del envenenamiento ofídico.

Snakebite envenoming is an accidental, non-infectious, non-contagious disease, caused by the effects of snake venoms. This disease is a relevant worldwide public health problem in tropical countries. Agricultural workers are highly exposed and therefore, commonly affected. The occurrence of snake envenoming involves some ethics concerns. In this assay, the moral significance of venomous snakes under anthropocentric and biocentric perspectives is discussed. Occupational risk and vulnerability of agricultural workers are also addressed. The ethical roles of government, agricultural enterprises and consumers in the occurrence of the disease are analyzed to try to explain why snakebite envenoming is a neglected disease. Finally, the role of the emerging social epidemiology as the contributor factor to gain involvement of stakeholders ‒which should be responsible for mitigation, prevention, treatment and control of snakebite envenoming‒ is discussed.

Evidence of complement-mediated killing of Discocotyle sagittata (Platyhelminthes, Monogenea) oncomiracidia.

Discocotyle sagittata oncomiracidia were rapidly killed when incubated in naïve plasma and immune sera from both rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta), the killing proceeding at a faster rate with blood material from the latter fish species. The lethal activity of naïve plasma and immune sera was comparable. This was abolished after incubation at 45 degrees C for 30 min and by the addition of EDTA but not EGTA supplemented with Mg(2+), indicating that complement acting via the alternative pathway is responsible for the parasiticidal effect observed. Scanning electron micrographs showed varying degrees of surface disruption in larvae exposed to fish plasma, suggesting that complement acts by breaching the oncomiracidial tegument. Control (untreated) oncomiracidia showed no damage. Ultrastructural damage was more extensive in oncomiracidia exposed to brown trout plasma than to rainbow trout plasma for equal periods, suggesting that the complement cascade may be involved in mediating host susceptibility.

[Comparative effects of complement inhibitors in vitro and in vivo experiments: an immunoenzyme method in studying subcomponent C1q inhibition and complement inhibition in model animals]. / Sravnenie deistviia ingibitorov komplementa v opytakh in vitro and in vivo: immunofermentnyi metod izucheniia ingibirovaniia subkomponenta C1q i ingibirovaniie deistviia komplementa na model'nykh zhivotnykh.

Methods of analysis of inhibition of complement system in vitro and in vivo have been developed for study of effects of medical drugs on the complement. The first one, ELISA method, for determination of inhibition of the first stage of complement activation includes binding of C1q subcomponent to immunoglobulin. The second method is based on capacity of mink serum to kill mice at the intravenous administration due to the action of mink complement. The effects of heparin, known anticoagulant, and suramin, used for treatment of trypanosomiasis, have been studied using these systems. The inhibition constants of binding suramin and heparin binding evaluated by the first method C1q were 411 +/- 29 micrograms/ml (or 0.287 +/- 0.020 mumole/l) and 36.4 +/- 1.7 micrograms/ml (or 2.28 +/- 0.10 mmole/l), respectively. This indicates that heparin binding with C1q in 10 times is higher, than that for suramin (as weight ratio) or 100 times higher in molar ratio. Administration of 3 mg of suramin or 0.3 mg of heparin to mice protected them against lethal action of intravenously injected 0.08 ml of mink serum. Blood concentrations of these compounds approximately correspond to inhibition constants for C1q binding, obtained using in vitro method.

Increase production of fibronectin by glomerular cultures from rats with nephrotoxic nephritis. Macrophages induce fibronectin production in cultured mesangial cells.

BACKGROUND: The participation of monocytes-macrophages and their products in the pathogenesis of several types of glomerulonephritis has become increasingly evident. One of the most important aspects is the potential stimulation of monocyte-macrophages of the extracellular matrix. Therefore, production of fibronectin (FN) by glomeruli of rats with nephrotoxic nephritis was studied. In addition, the effect of macrophage-conditioned medium and interleukin-1 on FN production by cultured mesangial cell (MC) was tested. EXPERIMENTAL DESIGN: Nephrotoxic nephritis was induced in rats by injection of nephrotoxic serum and glomeruli obtained at different periods of time from nephritic and normal animals were cultured. FN in glomerular supernatants was determined by enzyme-linked immunosorbent assay and newly synthesized FN by incorporation of [35S]-methionine. Macrophage-conditioned medium was obtained from cultures of peritoneal resident macrophages and elicited macrophages by different stimuli. MC were cultured with or without macrophage supernatant or interleukin-1 and FN content from MC supernatants was determined by enzyme-linked immunosorbent assay. RESULTS: These data show increase amounts of FN in nephritic cultures when compared with saline controls (time of nephritis; day 4: 3.9-, day 8: 4.35-, and day 18: 2.68-fold increase in FN) and experiments of newly synthesized FN by incorporation of [35S]-methionine had similar results. Macrophage-conditioned medium had FN stimulatory effect on cultured MC but interleukin-1 did not. CONCLUSIONS: These data suggest: (a) that there is an increased newly synthesized FN production in glomeruli from rats with nephrotoxic nephritis, (b) that macrophage produce a FN-stimulatory factor(s) for MC, and (c) that this stimulatory factor probably is not interleukin-1.