Plastination is a preservation method for biological specimens, with important advantages over classic conservation techniques with formaldehyde or alcohol. Plastinated specimens are dry, odourless, and free of carcinogenic and toxic solutions. There are only few references about the plastination of parasites. Moreover, there is no information on the effect of plastination on the morphology and morphometry of these animals. The aim of this study was to define a plastination protocol to preserve various species of parasites, namely the nematodes Parascaris equorum (Goeze, 1782); Ascaris suum Goeze, 1782 and Dirofilaria immitis (Leidy, 1856); the acanthecephalan Macracanthorhynchus hirudinaceus (Pallas, 1781); the trematodes Fasciola hepatica Linnaeus, 1758 and Dicrocoelium dendriticum (Rudolphi, 1819) and the tapeworm Taenia sp. in the best morphological and morphometric conditions. Results showed that some individuals suffered collapse (P. equorum, A. suum, and D. dendriticum). However, other parasites presented good results with almost no change after plastination (D. immitis, M. hirudinaceus and F. hepatica). In conclusion, conventional plastination allowed anatomical preservation of all helminths tested, but modifications to the protocol are needed to prevent collapse., Moisés Gonzálvez, Juana Ortiz, María Navarro, Rafael Latorre., and Obsahuje bibliografii
Diverse classes of fuzzy relations such as reflexive, irreflexive, symmetric, asymmetric, antisymmetric, connected, and transitive fuzzy relations are studied. Moreover, intersections of basic relation classes such as tolerances, tournaments, equivalences, and orders are regarded and the problem of preservation of these properties by n-ary operations is considered. Namely, with the use of fuzzy relations R1,…,Rn and n-argument operation F on the interval [0,1], a new fuzzy relation RF=F(R1,…,Rn) is created. Characterization theorems concerning the problem of preservation of fuzzy relations properties are given. Some conditions on aggregation functions are weakened in comparison to those previously given by other authors.
An organ-preserving solution, including in its composition also organic molecules, prepared at the University of Wisconsin (UW), has been successfully used for preservation of liver, pancreas and kidney, and has recently been tested for long-term storage of isolated hearts. We have compared the effectiveness of the UW solution with that of a standard crystalloid cardioplegic solution (St. Thomas, ST) in the functional and structural preservation of isolated hearts. The hearts taken from 24 rabbits were mounted on a Langendorff preparation. After assessment of the left ventricular function by an intraventricular balloon, 40 ml of either cardioplegic solution were injected to arrest the hearts (12 UW and 12 ST), which were then immersed in the same solution for 4 h at 4 °C without perfusion. After this period, the hearts were normothermally reperfused with oxygenated Krebs-Henseleit solution for 30 min, and finally left ventricular function was assessed again. An electron microscopic evaluation was performed as well. Significantly higher recovery of left ventricular developed pressure (p<0.01) and of negative dP/dt (p<0.05), was observed after preservation with UW, while no difference on positive dP/dt was found. After reperfusion, left ventricular end-diastolic pressure significantly rose with ST (p<0.01), but did not change with UW; the difference between ST and UW was significant (p<0.01). Tissue water content was significantly lower in the hearts preserved with UW (p<0.05). Electron microscopic examination revealed generally good preservation with no substantial difference between the two solutions. We conclude that UW cardioplegic solution, rather than ST solution, associated with low temperature, provides better protection of isolated hearts against ischaemia and reperfusion injury after long-term preservation. This is probably due to the combined effects of antioxidants, cell- membrane impermeable substances and oncotic agents.