Fetal Swine Research Articles

Two independent lipoprotein receptors on hepatic membranes of dog, swine, and man. Apo-B,E and apo-E receptors.

We have reported previously that canine livers possess two distinct lipoprotein receptors, an apoprotein (apo)-B,E receptor capable of binding the apo-B-containing low density lipoproteins (LDL) and the apo-E-containing cholesterol-induced high density lipoproteins (HDLc), and an apo-E receptor capable of binding apo-E HDLc but not LDL. Both the apo-B,E and apo-E receptors were found on the liver membranes obtained from immature growing dogs, but only the apo-E receptors were detected on th hepatic membranes of adult dogs. In this study, the expression of the apo-B,E receptors, as determined by canine LDL binding to the hepatic membranes, was found to be highly dependent on the age of the dog and decreased linearly with increasing age. Approximately 30 ng of LDL protein per milligram of membrane protein were bound via the apo-B,E receptors to the hepatic membranes of 7- to 8-wk-old immature dogs as compared with no detectable LDL binding in the hepatic membranes of adult dogs (greater than 1--1.5 yr of age). Results obtained by in vivo turnover studies of canine 125I-LDL correlated with the in vitro findings. In addition to a decrease in the expression of the hepatic apo-B,E receptors with age, these receptors were regulated, i.e., cholesterol feeding suppressed these receptors in immature dogs and prolonged fasting induced their expression in adult dogs. Previously, it was shown that the apo-B,E receptors were induced in adult livers following treatment with the hypocholesterolemic drug cholestyramine. In striking contrast, the apo-E receptors, as determined by apo-E HDLc binding, remained relatively constant for all ages of dogs studied (10--12 ng/mg). Moreover, the expression of the apo-E receptors was not strictly regulated by the metabolic perturbations that regulated the apo-B,E receptors. Similar results concerning the presence of apo-B,E and apo-E receptors were obtained in swine and in man. The hepatic membranes of adult swine bound only apo-E HDLc (apo-E receptors), whereas the membranes from fetal swine livers bound both LDL and apo-E HDLc (apo B,E and apo-E receptors). Furthermore, the membranes from adult human liver revealed the presence of the apo-E receptors as evidenced by the binding of 12--14 ng of HDLc protein per milligram of membrane protein and less than 1 ng of LDL protein per milligram. The membranes from the human liver also bound human chylomicron remnants and a subfraction of human HDL containing apo-E. These data suggest the importance of the E apoprotein and the apo-E receptors in mediating lipoprotein clearance, including chylomicron remnants, by the liver of adult dogs, swine, and man.

Comparative studies on cell lines established from normal and radiation-exposed miniature swine

Cloned cell lines were established from two swine with radiation-induced myeloproliferative disorders, including one cell culture from an animal with myelogenous leukemia and one from an animal with myeloid metaplasia. A third cloned cell line with similar morphology was established from pooled normal fetal swine cornea to compare the growth characteristics of cells from normal and irradiated swine. All three cell lines grew as foci of aggregated cells and were able to form macroscopic colonies in semisolid agar medium. The lack of normal mechanisms of contact inhibition and the observed aneuploidy indicated that these cells were morphologically transformed. Further, the cloned cells caused tumors in nude mice, clearly indicating that these cells were also malignantly transformed. A major difference between these cell lines was that type C viruses were observed only in the cells derived from swine with myeloproliferative disorders.

In vitro lymphocyte reactivity to soluble tumor extracts in sinclair melanoma swine

AbstractAn antigen‐stimulated active rosette assay was adapted as an in vitro assay for the detection of lymphocyte reactivity to soluble tumor extracts. The specificity of this assay was demonstrated with lymphocytes from non‐sensitized swine and swine sensitized to either mammalian tuberculin or DNCB‐bovine serum albumin conjugates (DNCB‐BSA). An increase in active rosette‐forming cells (A‐RFC) occurred only when sensitized lymphocytes were stimulated with specific sensitizing antigen. Lymphocytes from melanoma swine reacted in vitro to 3 M KCl extracts of autologous and allogeneic melanomas but did not react to 3 M KCl extracts of autologous and allogeneic swine skin. Lymphocytes from 33 melanoma swine and 17 normal swine were tested for in vitro reactivity to an allogeneic melanoma extract; 84.8% of the melanoma swine demonstrated lymphocyte reactivity to allogeneic melanoma extract and 23.5% of the normal swine reacted positively to allogeneic melanoma extract. The reactivity of melanoma swine lymphocytes to allogeneic melanoma extract was not due to reactivity of the lymphocytes to normal skin antigens or fetal swine antigens present in melanoma extracts; normal and melanoma swine lymphocytes demonstrated only low in vitro reactivity to 3 M KCl extracts of normal swine skin and fetal swine tissue. Lymphocytes from three melanoma swine increased in A‐RFC after incubation with each of nine allogeneic melanoma extracts, indicating that the ability to stimulate lymphocyte reactivity was not limited to a single allogeneic melanoma extract. The results of this study indicate that a tumor‐related immune response occurs in melanoma swine and that in vitro lymphocyte reactivity is directed towards a tumor‐associated antigen or tumor‐associated antigen‐like substance present in 3 M KCl extracts of swine melanoma.

Binding of fatty acids and tryptophan to alpha-fetoprotein from fetal pigs

Using gel electrophoresis and autoradiography, we have shown that palmitic, stearic, oleic and arachidonic acids as well as tryptophan bind to alpha-fetoprotein derived from fetal swine serum. It is also shown that these ligands bind to albumin from both fetal and adult swine serum. The results suggest that alpha-fetoprotein in the fetus has transport functions similar to albumin in the adult.

Lipogenic capacity of liver from perinatal swine ( Sus domesticus)

1. 1. Late fetal swine have marginal fatty acid synthesis in the liver as indicated by carbon flux studies with slices. This is in contrast to many other species. 2. 2. Several enzyme activities normally associated with lipogenesis are present in prenatal animals at moderate levels and most do not markedly fluctuate with age.

Connective tissue metabolism in swine. 3. The influence of methallibure on connective tissue development in fetal swine.

THE influence of the administration of methallibure to gravid sows between the 29th and 50th day or the 39th and 60th day of gestation on the levels of collagen, mucopolysaccharide, calcium and phosphorus in skin, aorta, cranial bones, humerus, ulna, radius and metacarpals of fetal pigs at term was studied. Methallibure treatment resulted in increased levels of collagen and decreased concentrations of mucopolysaccharide in skin and aorta. There was a significantly increased concentration of calcium in the skin of pigs from sows which had received methallibure between the 29th and 50th day of gestation. The influence of methallibure treatment on bones was unique for each bone. The shaft of the humerus and the entire radius and ulna showed increased levels of collagen and calcium and decreased amounts of mucopolysaccharide. The metacarpals and the epiphyses of the humerus showed only minimal response to methallibure treatment. The principal changes found in the cranial bones were increased calcium levels and decreased mucopolysaccharide concentrations in bones from both groups which received metallibure. The observations were explained in terms of a differential effect of methallibure on the cells which synthesize mucopolysaccharide and collagen in bones and soft tissues.

Ascorbate metabolism in swine. Influence of maternal hypoxia on fetal tissue ascorbate levels.

The effects of birth on tissue and serum ascorbate levels as well as the influence of maternal hypoxia on fetal tissue and serum ascorbate levels were investigated. Serum and adrenal ascorbate levels in neonatal swine were drastically decreased when compared with near-term (112-day-old) fetal swine. Kidney, cardiac, and muscle ascorbate levels also were found to be decreased on birth although liver levels in the newborn rose significantly above fetal levels. Hypoxic stress produced by decreasing the oxygen concentration in the maternal gas supply produced effects in 112-day-old fetal pigs which were similar to those noted for birth. An hypothesis was presented to explain the observation in which it was suggested that ascorbate may have a key role in the mechanism by which the fetal pig successfully coped with the stress of birth.

The vasa sanguinea vasorum of the fetal aorta of domestic swine.

In 122 aortas of swine fetuses of various ages the vasa sanguinea vasorum were investigated. The repartition of the vasa sanguinea vasorum was affected by age and the thickness of the media. Only aortic segments whose media included more than 29 lamellar units were vascularized.

GROWTH OF THE SWINE FETUS.

GROWTH OF THE SWINE FETUS.

Intestinal Lactase, Alkaline and Acid Phosphatase in the Swine Fetus and Newborn Pig

Intestinal Lactase, Alkaline and Acid Phosphatase in the Swine Fetus and Newborn Pig

Effect of stage of gestation on succinoxidase activity of fetal and maternal swine hearts.

SummaryA significant increase in the succinoxidase activity of fetal swine ventricles was found to occur during the latter half of gestation, on both the wet weight and per unit of nitrogen basis. As gestation approached termination, an increase in activity occurred in the left ventricles of the maternal heart. These observations show that in large animals the fetal heart increases in succinoxidase activity with increased function, as previously demonstrated in the rat and chick; and that the later stages of gestation make increased requirements of the heart as indicated by greater maternal heart enzymatic activity. Two dietary levels of Mn and position of the fetuses in the uteri had no influence on the succinoxidase activity.