RESUMEN
Amides were tested as internal cryoprotectants for the preservation of wild silverside (Odontesthes bonariensis) sperm. The semen was diluted in modified Mounib's medium and cryopreserved by adding 2, 5, 8 or 11% of dimethyl acetamide (DMA), dimethyl formamide (DMF) or methyl formamide (MF). Dimethyl sulfoxide (DMSO) at a concentration of 10% diluted in modified Mounib's medium was used as a control. The rate motility (17.7 ± 1.9%) and time motility (143.2 ± 9.7 s) (P < 0.05) of the sperm were higher with 2% DMF when compared with the other treatments. Despite the better motility results obtained with 2% DMF, the solution was not able to maintain cellular structure integrity of the cryopreserved sperm. The 10% DMSO and 8% MF treatment allowed for completeness of the plasma membrane (34.8% and 29%), functional mitochondria (19.8% and 16.2%) and plasma membrane fluidity (39.4% and 46.4%); furthermore, rate motility (11.8% and 10%) and time motility (81.4 s and 71.8 s) of the sperm were found to be at suitable levels when compared with 2% DMF. Thus, our evaluation suggests that 10% DMSO and 8% MF provide better cryopreservation of O. bonariensis sperm cells.
Asunto(s)
Criopreservación/métodos , Crioprotectores/farmacología , Formamidas/farmacología , Preservación de Semen/métodos , Acetamidas/farmacología , Animales , Membrana Celular/efectos de los fármacos , Dimetilsulfóxido/farmacología , Dimetilformamida/farmacología , Peces , Masculino , Semen/efectos de los fármacos , Motilidad Espermática/efectos de los fármacos , Espermatozoides/efectos de los fármacosRESUMEN
A family of 2-pyridineformamide-derived thiosemicarbazones and their gallium(III) complexes were tested against several isolates of pathogenic Cryptococcus strains. On complexation the antifungal activity significantly increases, suggesting coordination to gallium(III) to be an interesting strategy of antifungal dose reduction.
Asunto(s)
Antifúngicos/farmacología , Cryptococcus/efectos de los fármacos , Formamidas/farmacología , Galio/farmacología , Piridinas/farmacología , Tiosemicarbazonas/farmacología , Criptococosis/microbiología , Sinergismo Farmacológico , Humanos , Pruebas de Sensibilidad MicrobianaRESUMEN
The aim of the present work was to compare the efficiency of methyl-formamide (MF), dimethyl-formamide (DF) and glycerol (GL) as cryoprotectants in canine semen cryopreservation. For the experiment, pooled semen was submitted to one of the three cryoprotectants, with a final concentration of 3% in egg yolk-TRIS extender. Semen was subjectively evaluated for total and progressive motility, vigour and morphology. Sperm membrane functional integrity was assessed by hypo-osmotic swelling test (HOST), and longevity was assessed using the thermoresistance test (TRT). Fresh semen showed normal physical and morphological characteristics. After thawing, differences were observed between semen frozen using GL and DF, regarding total and progressive motility and vigour (p < 0.05), but not between MF and GL or MF and DF. Means for total motility, progressive motility, vigour and morphologically normal spermatozoa were, respectively, 69.0 +/- 5.4%, 61.0 +/- 7.4%, 2.9 +/- 0.5 and 57.1 +/- 5.0% for GL; 59.0 +/- 8.9%, 50.0 +/- 10.0%, 2.5 +/- 0.7 and 66.9 +/- 7.7% for MF; and 44.0 +/- 21.0%, 37.0 +/- 19.8%, 2.1 +/- 0.6 and 61.1 +/- 5.5% for DF. On HOST, GL was superior (p < 0.05) to MF and DF (57.8 +/- 12.4%, 35.8 +/- 18.4% and 34.4 +/- 9.4%, respectively). During the TRT, both GL and MF were superior to DF, with no differences between GL and MF. In conclusion, the use of MF as cryoprotectant showed results similar to GL, and can be considered as an alternative in canine semen cryopreservation. Further studies testing different concentrations of MF may improve its effects on cryopreservation of canine semen.
Asunto(s)
Criopreservación/veterinaria , Dimetilformamida/farmacología , Perros/fisiología , Formamidas/farmacología , Glicerol/farmacología , Preservación de Semen/veterinaria , Animales , Criopreservación/métodos , Crioprotectores/farmacología , Calor , Masculino , Preservación de Semen/métodos , Espermatozoides/citología , Espermatozoides/efectos de los fármacos , Espermatozoides/fisiologíaRESUMEN
1. Guinea pig papillary muscle in vitro upon exposure of Formamide (FMD) exerts a dose dependent positive inotropic effect. 2. The increase in tension developed by papillary muscle is associated with a marked decrease in the duration of the action potential. 3. The increase in extracellular calcium concentration does not modify the positive inotropic effect, but increases the duration of the action potential. 4. FMD markedly potentiate the increase in tension induced by caffeine 3 M suggesting a possible synergetic effect upon the release of Ca2+ ions from the S.R. 5. These experiments suggest that FMD increases the intracellular calcium concentration by exerting a direct action on intracellular calcium stores.
Asunto(s)
Formamidas/farmacología , Corazón/efectos de los fármacos , Potenciales de Acción/efectos de los fármacos , Animales , Cafeína/farmacología , Calcio/metabolismo , Electrofisiología , Cobayas , Corazón/fisiología , Ventrículos Cardíacos/efectos de los fármacos , Ventrículos Cardíacos/metabolismo , Técnicas In Vitro , Contracción Miocárdica/efectos de los fármacos , Miocardio/metabolismo , Músculos Papilares/efectos de los fármacos , Músculos Papilares/fisiología , Función VentricularRESUMEN
1. Effects of PCP at the frog neuromuscular junction were studied in vitro in sciatic nerve sartorius muscle of the toad Pleurodema-thaul. 2. Within the concentration 0.003-0.1 mM, PCP caused a dose-time-dependent block of evoked transmitter release acompanied by an increase in the rate of spontaneous quantal release. 3. PCP induced an increase in miniature endplate potential (MEPP) frequency and it was not antagonized in a Ca2(+)-free medium, indicating that it does not depend upon Ca2+ influx from the external medium, but may act by releasing Ca2+ from intraterminal stores. 4. The present data, together with previous results concerning PCP at eighth sympathetic ganglia indicate that 3,4-diaminopyridine (3,4-DAP) counteracts the effects of PCP on synaptic transmission. This result suggests that PCP interfering Ca2+ influx occurs during depolarization of motor nerve terminals.