Accuracy of ultrasonography for pregnancy diagnosis on days 10 to 22 in heifers

Two operators independently conducted ultrasonic pregnancy examinations on nulliparous Holstein heifers on Days 10, 12, 14, 16, 18, 20 and 22, and assigned a diagnosis (pregnant or nonpregnant) and a score for degree of certainty in the diagnosis (1, 2 or 3 for low, intermediate or high, respectively). Pregnancy was retrospectively confirmed by the ultrasonographic detection of an embryo proper and embryonic heartbeat on Day 24 in 20 25 bred heifers; the five nonpregnant heifers were excluded from the analyses. Eleven nonbred heifers were included as an unequivocal source of nonpregnant heifers. Accuracy was not significantly greater than a guess (50%) before Day 18, but reached 100% on Days 20 and 22. Mean accuracy was higher (P<0.005) for nonpregnant (65 77 , 84%) than pregnant heifers (91.5 140 , 65%). For certainty score, there were main effects of day (P<0.0001), reproductive status (pregnant or nonpregnant, P<0.003), and an interaction of day and reproductive status (P<0.0001). The certainty score increased in all heifers among days and was higher (P<0.05) in pregnant than nonpregnant heifers on Days 16 to 20. For luteal area (area of corpus luteum, excluding area of fluid filled center, if present), there were significant main effects of day, reproductive status and a day by status interaction (P<0.0001 for each). Luteal area was approximately constant in pregnant heifers, but in nonpregnant heifers it was lower (P<0.05) on Days 16 to 22 than on Days 10 to 14. Uterine echotexture was scored on a scale of 1 to 3, characteristic of a diestrus, intermediate and estrus uterus, respectively. There were main effects of day and reproductive status (P<0.0001 for each) and an interaction of day and reproductive status (P<0.025). Uterine echotexture was approximately constant in pregnant heifers, but in nonpregnant heifers it was higher (P<0.05) on Days 16 to 22 than on Days 10 to 14. Pregnancy diagnosis on Days 10 to 14 was based on detection of the conceptus; however, detection of the conceptus was not accurate prior to visualization of the embryo proper (mean Day 22, range Days 20 to 24). In nonpregnant heifers, a correct diagnosis with high certainty was made when a small corpus luteum and uterine echotexture characteristic of estrus were detected. In the absence of these changes on Days 18 to 22, a diagnosis of pregnancy was made with high accuracy and intermediate or high certainty.     

Regulation of protein phosphorylation and sodium transport in toad bladder

It is well established that active sodium-ion transport and water flow across isolated toad bladder are increased by antidiuretic hormone (ADH) and by cAMP. These agents were also observed in previous studies to cause changes in the amount of radioactive phosphate in a specific protein in the toad bladder. This protein, found by SDS-polyacrylamide gel electrophoresis of toad bladder epithelial preparations, had an apparent molecular weight of 49,000 daltons. In the present study, a correlation was found between the ability of a variety of substances to affect the amount of radioactive phosphate in this 40,000-dalton protein and their ability to alter the rate of sodium transport. Thus several agents (ADH, cAMP, theophylline, adenine, prostaglandin E1, and Mn Cl-2) caused a decrease in the amount of radioactive phosphate in the 49,000-dalton protein and also stimulated active sodium transport across the bladder. Conversely, ZnCl-2 produced an increase in the amount of radioactive phosphate in this protein and an inhibition of sodium transport. With each of these agents, the time-course of change in phosphorylation of this protein was, in general, similar to that for sodium transport. A second phosphoprotein, with an apparent molecular weight of about 42,000 daltons, showed changes in parallel with, but less extensive than, those observed in the 49,000 dalton protein. There was no consistent relationship between changes in level of phosphorylation of either in the 49,000- or 42,000- dalton protein and changes in osmotic water permeability. The results are compatible with the possibility that regulation by ADH and by cAMP of sodium transport in the toad bladder epithelium may be mediated through regulation of the amount of phosphate in a specific protein.     

Characteristics of Sodium Flux from Serosa to Mucosa in Rabbit Ileum

Sodium flux from serosa to mucosa, J_sm^Na in rabbit ileum in vitro has been studied as a function of applied electrical potential at equal sodium concentrations in the bathing solutions. The results indicate that J_sm^Na involves two pathways, a diffusional flux through a paracellular shunt pathway and a flux that is independent of applied potential and presumably involves a transcellular pathway. The latter pathway comprises approximately 25 % of J_sm^Na in Ringer's solution containing 10 mM glucose and 25 mM bicarbonate. It is stimulated significantly by theophylline unaffected by removal of glucose or addition of ouabain but is reduced to negligible values by anoxia, dinitrophenol, and replacement of all chloride and bicarbonate by isethionate. Thus this component of J_sm^Na has a number of characteristics consistent with involvement in a specific secretory process mediating an electrically neutral secretory transport of sodium plus anion from serosa to mucosa. In addition to stimulating this process, theophylline significantly reduced the permeability of the paracellular shunt pathway to sodium.     

Characteristics of the Amino Acid Transport System in the Mucosal Border of Rabbit Ileum

The specificity of the neutral amino acid transport system in the brush border was examined by studying the ability of amino acid analogues to inhibit the unidirectional influx of phenylalanine from mucosal solution into the cells. Effects were evaluated in terms of the affinity of various substrates for the amino acid site in the transport system. The affinity of amino acids for the site was proportional to the number of carbon atoms in the side chain. Electron-withdrawing substituents in the ring of phenylalanine increased affinity and electron-releasing groups decreased affinity. Removal of the α-amino group from phenylalanine decreased affinity by a factor of approximately 50 and removal of the carboxyl group decreased affinity 12-fold. Effects on affinity of variations in the side chain of the amino acid can be comparable in magnitude to that of the carboxyl group. The effect of sodium ion on the transport system appears to be similar for all compounds tested.     

The Sodium-Alanine Interaction in Rabbit Ileum : Effect of sodium on alanine fluxes

The model of the interaction between Na and alanine at the mucosal border of rabbit ileum has been tested further by examining the efflux of alanine from the cells toward the mucosal solution. Alanine efflux shows a tendency toward saturation as cellular alanine concentration increases and is influenced by cellular Na concentration. A decrease in cell Na concentration causes an increase in the apparent Michaelis constant with little change in maximal efflux rate. Studies on strips of mucosa treated with ouabain or cyanide showed that the direction of net alanine transfer between the cells and the medium is determined by the direction of the Na concentration difference. The cells extrude alanine against a concentration difference when cell [Na] exceeds medium [Na] and accumulate alanine when cell [Na] is less than medium [Na]. The observations are consistent with the model previously suggested involving a transport site that combines with and translocates both Na and alanine, and with the concept that the Na concentration difference between mucosal solution and cytoplasm provides at least part of the energy for active transport of alanine.     

Analysis of FBJ-MuSV provirus and c-fos (mouse) gene reveals that viral and cellular fos gene products have different carboxy termini

The complete nucleotide sequence of the FBJ-MuSV proviral DNA and the cellular homolog (c-fos) of its oncogene (v-fos) have been determined. The 4026 nucleotide long FBJ-MuSV proviral DNA contains two long terminal repeats, a substitution of 1639 nucleotides of mouse cellular DNA (v-fos) and the 3′ end of the env gene derived from FBJ-MuLV. The sequences of the parental FBJ-MuLV and the cellular c-fos (mouse) gene share five of five nucleotides at the 5′ end and ten of 11 nucleotides at the 3′ end of the v-fos substitution. When compared with the v-fos sequences, the c-fos gene contains four discontinuous regions, three of which are flanked by sequences characteristic of introns. Direct sequence analysis of c-fos (mouse) RNA by primer extension demonstrates that the fourth discontinuity is due to a 104 bp deletion in the v-fos gene. As a consequence of the deletion, the predicted v-fos and c-fos gene products differ at their C termini.     

Structure of the FBJ murine osteosarcoma virus genome: molecular cloning of its associated helper virus and the cellular homolog of the v-fos gene from mouse and human cells.

The 8.2-kilobase (kb) unintegrated circular DNA form of the FBJ murine leukemia virus (FBJ-MLV) was linearized by cleavage at the single HindIII site, molecularly cloned into bacteriophage Charon 30, and subsequently subcloned into pBR322 (pFBJ-MLV-1). Both FBJ-MLV virion RNA and pFBJ-MLV-1 DNA were used to investigate the arrangement of helper virus sequences in the FBJ murine osteosarcoma virus genome (FBJ-MSV) by heteroduplex formation with cloned FBJ-MSV proviral DNA. The results showed that the FBJ-MSV genome contained 0.8 kb of helper virus sequence at its 5' terminus and 0.98 kb at its 3' terminus. Approximately 6.8 kb of helper virus sequence had been deleted, and 1.7 kb of unrelated sequence was inserted into the FBJ-MSV genome. This substituted region contains v-fos, the transforming gene of FBJ-MSV. Using a probe specific for v-fos, we have cloned homologous sequences (c-fos) from mouse and human chromosomal DNA. Heteroduplex analysis of FBJ-MSV DNA with these recombinant clones showed that both the c-fos(mouse) and the c-fos(human) sequences hybridized to the entire 1.7-kb v-fos region. However, five regions of homology of 0.27, 0.26, 0.14, 0.5, and 0.5 kb were separated by four regions of nonhomology of 0.76, 0.55, 0.1, and 0.1 kb from 5' to 3' with respect to the FBJ-MSV genome. The size of these sequences showed striking similarity in both c-fos(mouse) and c-fos(human).     

The Effect of Ca and Antidiuretic Hormone on Na Transport across Frog Skin : I. Examination of interrelationships between Ca and hormone

Ca added to the solution bathing the outside of isolated frog skin causes a decrease in net Na transport across the skin while antidiuretic hormone (ADH) causes an increase. Possible interrelations between the effects of these agents have been examined. The decrease in Na transport caused by Ca was the same before and after treatment of the skin with ADH and the increase in transport caused by ADH was unaffected by the presence of Ca. The relationship between Ca concentration and degree of inhibition of Na transport was not appreciably altered by ADH. These results indicate that Ca and ADH do not compete but act independently at two different sites and these sites appear to be located on the same barrier to Na movement in the skin. Further, Ca causes a decrease in Cl influx across the short-circuited skin but ADH has no effect on Cl movement, again suggesting that the actions of these agents are independent.