Electrothermal branding for embryo labeling
A novel embryo labeling technique based on electrothermal branding is developed. Two types of micro branding irons are fabricated and tested. One utilizes 25 /spl mu/m tungsten wire as the heating element. The other utilizes surface micromachining techniques to fabricate polysilicon branding irons. The thermal behavior of the branding irons and the heat distributions in the embryos are analytically modeled. Micron-scale labels on unfertilized bovine embryos are achieved.
Capacitation of bull spermatozoa and fertilization in vitro of cattle follicular oocytes matured in culture.
The maturation ofovarian oocytes in vitro and fertilization after transfer to mated animals have been reported for rabbits (Chang, 1955), sheep (Crosby, Ryan & Gordon, 1971), pigs (Motlik & Fulka, 1974; Leman & Dziuk, 1971) and cattle (Sreenan, 1970; Hunter, Lawson & Rowson, 1972). In-vitro maturation of follicular oocytes followed by successful fertilization in vitro has been reported for the mouse (Cross & Brinster, 1970; Iwamatsu & Chang, 1972; Mukherjee, 1972), rat (Niwa & Chang, 1975), hamster (Barros & Munoz, 1974), guinea-pig (Yanagimachi, 1974), rabbit (Brackett, Mills & Jeites, 1972) and man (Edwards, Bavister & Steptoe, 1969). There does not, however, appear to be any report on the fertilization in vitro offollicular oocytes matured in vitro for large domestic animals such as cattle. The present experiment was therefore performed to examine the possibility of capacitation ofbovine spermatozoa in reproductive tracts isolated from oestrous cows or in the uteri in situ of oestrous rabbits. Ovaries were removed from cows at a local slaughterhouse and returned to the laboratory in saline at 30°C within 1 h. Follicular were collected at 30CC by the (2-5 mm diam.) with a needle. The collected were washed twice with (KRB) 1 mg mg sodium pyruvate/100 ml, 241-9 mg sodium lactate/100 ml, 4 mg crystalline bovine serum (Armour)/ml, 50 pg streptomycin/ ml and i.u. penicillin/ml (Toyoda & Chang, The pH of the medium was adjusted
In Vivo Comparison of Synthetic Macroporous Filamentous and Sponge-like Skin Substitute Matrices Reveals Morphometric Features of the Foreign Body Reaction According to 3D Biomaterial Designs
Synthetic macroporous biomaterials are widely used in the field of skin tissue engineering to mimic membrane functions of the native dermis. Biomaterial designs can be subclassified with respect to their shape in fibrous designs, namely fibers, meshes or fleeces, respectively, and porous designs, such as sponges and foams. However, synthetic matrices often have limitations regarding unfavorable foreign body responses (FBRs). Severe FBRs can result in unfavorable disintegration and rejection of an implant, whereas mild FBRs can lead to an acceptable integration of a biomaterial. In this context, comparative in vivo studies of different three-dimensional (3D) matrix designs are rare. Especially, the differences regarding FBRs between synthetically derived filamentous fleeces and sponge-like constructs are unknown. In the present study, the FBRs on two 3D matrix designs were explored after 25 days of subcutaneous implantation in a porcine model. Cellular reactions were quantified histopathologically to investigate in which way the FBR is influenced by the biomaterial architecture. Our results show that FBR metrics (polymorph-nucleated cells and fibrotic reactions) were significantly affected according to the matrix designs. Our findings contribute to a better understanding of the 3D matrix tissue interactions and can be useful for future developments of synthetically derived skin substitute biomaterials.