This study was conducted on the atrioventricular node (AVN) and atrioventricular bundle (AVB) of fivefour-month-old ovine fetuses. The histological structure of these components was studied by routinehistological techniques and use of specific staining methods. The AVN was caudally located adjacent to theroot of the aorta. It was almost spherical in shape and consisted of twisty cells. The node...

Surface layer proteins (SLPs) are essential for induction of abortion by Campylobacter fetus subsp. fetus in experimentally challenged ewes. These proteins are encoded by multiple sap genes and vary in size and antigenicity. The role of SLP antigenic variation during experimental ovine infection was investigated. Following subcutaneous challenge, the SLPs were highly antigenic, and antibodies w...

Uterine and umbilical uptakes of plasma amino acids were measured simultaneously in eighteen singleton pregnant ewes at 130 ± 1 days gestation for the purpose of establishing which amino acids are produced or used by the uteroplacenta under normal physiological conditions and at what rates. The branched-chain amino acids (BCAA) had uterine uptakes significantly greater than umbilical uptakes. N...

sheep as an experimental animal has been used in many veterinary researches. the developmental study of the ovine cervicothoracic ganglion in the fetal stages will reveal the anatomy of the sympathetic nervous system in the adult sheep and morphological and morphometrical relation between this ganglion and surrounding structures. the aim of this research was to follow morphological and morphome...

Red cell life span within the fetal circulation has not been reported, although erythrocyte life span has been studied in the adult and newborn. The present study quantified red cell life span in 12 chronically catheterized fetal sheep at 97-136 days gestation (term = 150 days) with the use of autologous red cells labeled with [(14)C]cyanate. Cyanate forms a permanent covalent bond with hemoglo...

Early studies of amino acid transport across the ovine placenta suggested that amino acids taken up by the placenta from the maternal circulation are delivered to the fetus with no major loss (placental amino acid utilization) or addition (placental amino acid production) (1). Recent data indicate that for some amino acids, this suggestion is not valid, and that amino acid metabolism is an impo...