ABSTRACT
Intercornual fistulas were made in the uteri of 19 ewes in an attempt to induce chorionic fusion between fetuses. Ewes were 28 to 40 days pregnant with at least one fetus per horn. Sections were removed from the dorsomedial wall of each uterine horn, and left and right horns were sutured together around the openings to produce the fistulas. In some cases a doughnut-shaped sheet of silastic was inserted between the horns, and in most cases the chorioallantoic membranes of the respective fetuses were sutured to one another prior to suturing the uterine walls. In the 16 animals in which intercornual fistulas were constructed in the area of the intercornual ligament, no chorionic anastomosis was induced. In one of the three animals in which fistulas were produced distal to that ligament, the fistula remained patent 25 days post-surgery, and membranes of two female fetuses were joined, through the opening, by a narrow strand of chorionic tissue. We concluded that this technique was not a promising one for induction of choriovascular anastomosis.
Subject(s)
Chorion/surgery , Freemartinism/etiology , Genetic Engineering/veterinary , Membrane Fusion , Sheep Diseases/etiology , Sheep/surgery , Uterus/surgery , Animals , Cattle , Chorion/blood supply , Female , Microcirculation , PregnancyABSTRACT
Peripheral blood cultures were made on 20 Dorset sheep including 16 ewes and 4 rams. Photomicrographs of 100 cells were examined for trypsin-induced G-bands, and the length of each chromosome was measured. The banding patterns of each of the 27 pairs of chromosomes were identified and described, and the results observed in this study were compared with those previously reported. Measurements of all chromosomes in which both members of a homologous pair were identifiable were used to calculate mean relative length. Karyotypes, in which chromosomes were arranged to mean relative length, were prepared and an idiogram illustrating major bands was constructed.
Subject(s)
Chromatin/isolation & purification , Chromosomes/analysis , Staining and Labeling , Animals , Female , Karyotyping , SheepABSTRACT
Fertile White Leghorn eggs were injected with Aroclor 1242 and incubated for four to five days. More than 65 percent of the exposed embryos died prior to examination at the end of the incubation period. The five largest pairs of chromosomes from allantoic squashes were examined for the presence of chromosomal breakage in 753 metaphases from PCB-treated eggs and 196 metaphases from controls. Failure to detect chromosomal aberrations in either group indicated that Aroclor 1242, in concentrations of 10 p.p.m. or 20 p.p.m. in the egg, is not an effective clastogen in the chicken embryo.
