Browsing by Author "Wolff, Daniel"
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- ItemComparative study between conservative solutions with and without formaldehyde in human placenta(SOC CHILENA ANATOMIA, 2012) Wolff, Daniel; Villa, Pablo; Neirreitter, Alejandra; Ruibal, Cecilia; Armand Ugon, Gustavo; Salgado, Guillermo; Cantin, MarioThe fixation and conservation techniques of anatomic material are commonly performed with solutions containing formaldehyde, given its low cost. These have several disadvantages such as the irritating odor, stiffness, discoloration of the structures, toxicity, carcinogenic, teratogenic and mutagenic risk for those who are exposed. Therefore it is desirable to use solutions without formaldehyde. The aim of this study was to compare 2 methods of anatomical conservation, one with formalin (Montevideo's solution) and one without formalin (Prives method) using the human placenta as an experimental organ model evaluating its macroscopic parameters. We used 46 human placentas from normal deliveries and term pregnancy. The placentas were separated into two groups (n=22 and n=24 respectively). The first group of placentas was perfused with formaldehyde solution and the second group in a solution without formaldehyde. Then both groups were immersed and maintained in their respective solutions for two weeks and then withdrawn leaving the air at room temperature for 2 weeks. Quantitative variables were analyzed for weight and diameter of each piece, and qualitative variables as consistency, color, odor and growth of micro/macro organisms were evaluated. Data collection was performed prior to washing at 14, 21 and 28 days. The results showed that conserved placentas with Prives method showed better conservation in relation to its diameter, consistency, color and less irritating odor in relation to placentas treated with formalin solution. In no case was growth of micro or macro organism. In conclusion, using advantageously at alternative solutions to formaldehyde, as the formula of Prives method, better preserved macroscopic characteristics of placentas without generating an irritating smell, stopping the decomposition process.
- ItemLarge cation-selective pores from rat liver peroxisomal membranes incorporated to planar lipid bilayers(1986) Labarca, Pedro; Wolff, Daniel; Soto, Ubaldo; Necochea, Cecilia; Leighton, FedericoFusion of a highly purified fraction of rat liver peroxisomal membranes to planar lipid bilayers incorporates large, cation-selective voltage-dependent pores. ThePK/PCl ratio of these pores, estimated in KCl gradients, is close to 4. The pores display several conductance states and spend most of the time open at voltages near 0 mV, closing at more positive and negative voltages. At voltages near 0 mV the most frequent open state has a conductance of 2.4 nS in 0.3m KCl. At voltages more positive and more negative than 10 mV the most frequent open state displays a conductance of 1.2 nS in 0.3m KCl. With these results pore diameters of 3 and 1.5 nm, respectively, can be estimated. We suggest that these pores might account for the unusually high permeability of peroxisomes to low molecular weight solutes. Fusion also incorporates a perfectly anion-selective, two-open states channel with conductances of 50 and 100 pS in 0.1m KCl.