The role of Haemophilus somnus in early embryonic death. I. The effect of the organism on embryos by day 8 postbreeding

A study using 23 healthy, mature, virgin Holstein-Friesian heifers was designed to determine if H. somnus caused detrimental effects in early bovine embryos and the mechanism(s) that induced these effects. Superovulated heifers were artificially inseminated 12 and 24 h after standing estrus using highquality, Haemophilus-free semen from a single ejaculate of one bull. Treatment heifers (n=12) were exposed by intrauterine infusion 12 h after the second insemination to approximately 1.5 x 10(9)H. somnus organisms (Iowa strain 1229) suspended in 10 ml of sterile 0.85% phosphate buffered saline (PBS). Control heifers (n=11) were inseminated and the infused with sterile PBS. Embryos were recovered 8 d after the second insemination using non-surgical technique and evaluated microscopically and graded on their estimated survivability. Representative embryos were also examined for in vitro culture survival time, histopathological changes, vital stain uptake and bacterial contamination. Following embryo recovery, uterine flush solution was centrifuged at 10,000 x G. Sediment was submitted for bacteriologic examination and supernatant preserved for quantitation of H. somnus immunoglobulins. Results to date indicate that H. somnus had a detrimental effect on early bovine embryos. H. somnus was recovered from the tissues of one treated animal. Significantly more (P 相似文献   

Body surface area of the golden Syrian hamster.

The body surface areas (BSAs) of 30 Syrian hamsters were actually measured. From these areas, the Mass Coefficients (K values) for the Dubois and Dubois equation (5.31) and for the Meeh-Rubner equation (11.89), were computed. These values were independent of weight and sex. To verify the applicability of the Mass Coefficients, the BSAs of another 20 animals were calculated and compared with the actually measured BSAs. The difference between measured and calculated BSAs was not significant. Therefore, these values can be used with their respective equations to compute BSA in Golden Syrian hamsters.     

Analysis of the inhibitory effect of inorganic phosphate on development of four-cell hamster embryos in vitro

Hamster 4-cell stage embryos were cultured in a protein-free, glucose-free medium to study the nature of developmental inhibition by inorganic phosphate (Pi). In the absence of Pi, between 40 and 55% of embryos were able to develop to the blastocyst stage but addition of Pi to the medium reduced this proportion to 5-20%. The inhibition did not appear to be due to contamination of the Pi salt with heavy metals because EDTA did not relieve the effect. Inhibition by Pi showed no dose-response relationship over the range tested (1-350 microM). In contrast, another divalent anion (sulphate) produced no inhibition of 4-cell embryo development at concentrations as high as 5.6 mM. Embryos were less sensitive to inhibition by Pi after the third cleavage division had occurred, and development of mid or late 8-cell embryos was unaffected by Pi. After exposure to Pi for 1 h, embryos could recover and continue development but longer exposure was detrimental to subsequent development. These results indicate that the inhibitory effect is specific to phosphate ions, is not due to contaminants in the Pi salt, is evoked by very low concentrations of Pi, is stage-specific, and is reversible following brief exposure of embryos to Pi. These effects may be artifacts of the culture milieu, or they may reflect some unknown characteristic of the early cleavage stage hamster embryo.     

The effects of nitrous oxide on the developing hamster embryos

Pregnant hamsters were exposed to different concentrations of nitrous oxide during the period of organogenesis. Teratogenic effects were observed in a small but significant number of fetuses. Types of malformations included cleft palate, limb defects, gut herniation, and fetal edema. A dose-effect relationship was not observed. It is not clear from our observations whether the observed effect on the fetuses was due to the excess of nitrous oxide, hypoxia, or a combination of both. Comparison with published literature indicates that further studies on the effects of nitrous oxide in placental animals are needed.     

The effect of glutamine on the development of sheep embryos in vitro

The effects of glutamine (Gln) on the in vitro development of sheep embryos cocultured with sheep oviduct epithelial cells (SOEC) or cultured in medium alone were investigated. The in vitro development was evaluated after culture in synthetic oviduct fluid (SOF) medium to Day 6, and then the viability of some of the morula/blastocyst stage embryos was assessed by transfer into recipient ewes. In Experiment 1, sheep embryos were cultured from Day 2 to Day 6 in SOF containing 0 or 1 mM Gln with or without (SOEC) support in a 2 x 2 factorial design. An interaction was found between the effects of Gln and SOEC (P<0.001). The addition of Gln increased blastocyst formation (6%, 2 36 vs 35%, 11 31 ) and the rate of pregnancy (50%, 4 8 vs 100%, 5 5 ) when the embryos were cultured in medium alone, but had no beneficial effect in the presence of SOEC. In Experiments 2 and 3, sheep embryos were cultured from Day 1 to Day 6 in SOF supplemented with 1 mM Gln, with 1 mM alpha-ketoglutarate or without supplementation (control). In Experiment 2, no other amino acids were added, but in Experiment 3 SOF was supplemented with 19 other amino acids. In Experiment 2, when Gln was the only amino acid, the rate of blastocyst formation was increased by the addition of Gln (24%, 8 35 ), but alpha-ketoglutarate caused no increase in blastocyst formation (3%, 1 34 ) compared to the control group (6%, 2 34 ). In Experiment 3, when 19 other amino acids were added, neither Gln nor alpha-ketoglutarate affected the rate of blastocyst formation or the subsequent development of embryos in recipient ewes. These results showed that Gln, when used as a single amino acid, has a beneficial effect on the development of sheep embryos in serum free culture without somatic cells. The data suggest that Gln is used as a source of amino groups rather than as a source of energy since no beneficial effects were found when its deaminated carbon skeleton (alpha-ketoglutarate) was used or when other amino acids were present.     

Surgical day care: measurements of the economic payoff.

A careful and detailed cost analysis that measured all the costs, direct and indirect, generated in the course of an episode of surgical care demonstrated that there are very large savings from the substitution of surgical day care for inpatient care. Surgical day care appears to be an ideal alternative to inpatient care, from the points of view of those who pay for medical care (governments) as well as those who provide it (hospitals and health professionals) and those who receive it (patients). From an economic perspective the potential savings have not been achieved, and present policies provide no incentives to encourage these savings. These problems, together with strategies to encourage cost savings, are discussed.     

The hyperlipemic hamster - a model for testing the anti-atherogenic effect of amlodipine

Male Golden Syrian hamsters were subjected to a hyperlipemic diet. At intervals ranging from 2 to 14 weeks, the animals were examined for changes in serum constituents and structural modifications of lesion-prone areas: the cardiac valves, coronary arteries and aortic arch. Serum was characterized by a gradual increase in cholesterol, triglycerides and a decrease in total peroxyl-radical trapping potential. The sequence of modifications of the endothelial cells, smooth muscle cells, and migrating plasma monocytes as well as of the extracellular matrix were established. Amlodipine treatment of hyperlipemic hamster was assessed. Amlodipine exhibited an athero-protective effect, acting as antioxidant, reducing the LDL uptake by the vessel wall and consequently, limiting the size and extent of lesioned areas. The hyperlipemic hamster is a reliable model to unravel the cellular alterations leading to atheroma formation, and for testing the effect of drugs in this process.     

Influence of single amino acids on the development of hamster one-cell embryos in vitro

One-cell hamster embryos placed in culture have always shown a complete block to development at the two-cell stage. In a preliminary study using a chemically defined culture medium containing 20 amino acids (HECM-1), many one-cell embryos were able to escape the "two-cell block" and develop to the four-cell stage. Use of a simpler formulation containing only the amino acids hypotaurine and glutamine revealed marked inhibitory and stimulatory effects of adding the other amino acids. In the first experiment, 19 amino acids were separately examined for effects on one-cell embryo development. Six amino acids (phenylalanine, valine, isoleucine, tyrosine, tryptophan, and arginine) inhibited embryo development (reduced mean cell number; MCN), and three others (glycine, cystine, and lysine) stimulated development (increased MCN), compared with basic medium containing only glutamine and hypotaurine (low control). When the responses with the six inhibitory amino acids were totalled, only 3 of 185 (2%) one-cell embryos reached the six-or seven-cell stage compared to a total of 15 of 76 (20%) embryos that developed to these stages using the three stimulatory amino acids. When tested together in a second experiment, the six inhibitory amino acids significantly reduced the MCN, from 4.28 +/- 0.44 (low control) to 3.71 +/- 0.55. In this group, 17 of 117 (15%) of one-cell embryos reached more than four-cell and only 4 of 117 (3%) reached six- or 7-cell stages, compared with 39 of 117 (33%) and 12 of 117 (10%), respectively, for the basal medium group.(ABSTRACT TRUNCATED AT 250 WORDS)     

The role of Haemophilus somnus in bovine early embryonic death. III. The effect of the organism on embryos by day 21 postbreeding

A study using 11 healthy, mature Holstein-Friesian heifers was designed to determine whether 1) H. somnus induces gross and/or histopathological changes of the uterine tract and embryos, 2) H. somnus has a short and/or long-term effect on the ovarian activity, 3) prior exposure to H. somnus would modulate the effect of a second exposure to the organism. Superovulated heifers were artificially iseminated 12 and 24 h after standing estrus using high-quality, Haemophilus-free semen from a single ejaculate of one bull. Control heifers (Group 1, n = 2) were infused by intrauterine route, 12 h after the second insemination, with 10 ml of 0.85% sterile phosphate buffered saline (PBS) as a placebo. The treatment heifers were exposed by intrauterine infusion, 12 h after the second insemination, to approximately 1.5 x 10(9)H. somnus organisms (Iowa strain 1229) suspended in 10 ml of 0.85% sterile PBS. Group 2 (n = 2) treatment heifers were exposed 21 d prior to embryo recovery; Group 3 treatment heifers (n = 3) were exposed 5 mo prior to embryo collection; and Group 4 treatment heifers were exposed twice, 5 mo apart with the second exposure 21 d prior to embryo recovery. All animals were slaughtered and the whole genital tract was removed for pathological examination and embryo recovery. There were minimal pathological changes in the uterus. However, H. somnus significantly affected (P 相似文献   

Body surface area of Africans: a study based on direct measurements of Nigerian males

Direct measurement of body surface area (Ab) was made on 20 male adult Nigerians of African descent by coating and planimetry. The results were compared with estimated Ab values obtained using six widely accepted height and weight prediction equations. The results show that existing formulas do not predict surface areas of our subjects accurately. Measured Ab values of our subjects were 6-22% greater than predicted values obtained from non-African nomograms. Using these results, we computed new variables for height and weight formulas that accurately predict the surface area of Africans. The closest fit to measured values is given by the equation Ab(m2) = 0.001315 x Height 1.2139 (cm) x weight 0.2620 (kg) +/- 0.04815 (SEE). The new variables are significantly different from those of existing equations. Our height variable is several times greater than the weight variable and reflects a greater importance of height than weight in determining the surface area of Africans than is the case with Caucasians.     

The effect of exogenous nucleosides on postimplantation development of mouse embryos

Exogenous nucleosides, either singly or in combination, do not enhance postimplantation development of mouse embryos in vitro, and adenosine, guanosine and thymidine are toxic to the embryos at high concentrations.     

The effect of cell-to-cell contact on the surface morphology of Chinese hamster ovary cells

In the previous report (Porter et al., in this issue) morphological changes in Chinese hamster ovary (CHO) cells during the cell cycle were described. In this report we describe the role of intercellular contact on these changes. We find that intercellular contact is required for cells to exhibit the morphologies Porter et al. described for S and G₂. When cells are synchronized by mitotic selection and plated onto cover slips at very low density such that no intercellular contact occurs, the cells remain in a G₁ configuration (rounded and highly blebbed through G₁, S, and G₂). This G₁ morphology is also observed in nonsynchronized log phase cells plated at low densities and allowed to grow for several generations. The addition of conditioned medium from confluent cultures does not induce low density cells to change morphology during the cell cycle. These results indicate that extensive intercellular contact is required for the complete expression of the morphological changes associated with the cell cycle (as described by Porter et al.). It is concluded that although classic contact inhibition of movement and of growth may be absent in this transformed cell line, some contact-dependent response persists.     

The effect of oxygen on the development of preimplantation mouse embryos in vitro

The optimal oxygen tension for development of preimplantation mouse embryos to the blastocyst stage in vitro was found to be between 2.5% and 5%. One- and two-cell embryos had a more sharply defined range of oxygen tension capable of supporting development than 8-cell and morula stages. At all stages of development, more embryos developed to the blastocyst stage under 5% O2 compared to the numbers of developing under higher oxygen tensions (20% and 40% O2). The blastocysts developing under 20% O2 had fewer blastomeres than those which developed under 5% O2. As the time required for development to the blastocyst stage in vitro increased, there were fewer blastomeres present at the blastocyst stage. These results indicate that the cleaving mouse embryo has an optimal oxygen requirement in vitro of about 5%. At higher oxygen tensions, fewer embryos develop to the blastocyst stage and in those which do develop, there are fewer cell divisions. If a gradient of oxygen tension exists across the blastomeres from the outside of the embryo to its centre, the blastomeres might be using this gradient to obtain imformation about their location within the embryo and respond accordingly. Thus blastomeres on the outside at a higher oxygen tension would divide at a slower rate and form trophectoderm whereas those on the inside at a lower oxygen tension would divide more rapidly and contribute to the inner cell mass.     

The beneficial effect EDTA on development of mouse one-cell embryos in chemically defined medium.

An improved methology for culturing noninbred (ICR) mouse one-cell embryos is described. The successful development of one-cell embryos into blastocysts in chemically defined (Whitten's) medium was significantly enhanced by the presence of EDTA. More than 70% of ICR one-cell embryos developed into blastocysts in Whitten's medium in the presence of 10.8 μM EDTA, while, without EDTA, only 15–30% of embryos reached blastocyst stage. A concentration of 10.8 μM EDTA also promoted the development of 65–90% of inbred $\text{C57BL}\text{6}$ one-cell embryos in Whitten's medium. This beneficial role of EDTA is probably related to the chelation of some metal ion(s) other than Ca²⁺ or Mg²⁺.     

The relation between surface area and anchorage dependence of growth in hamster and mouse fibroblasts.

Anchorage dependence can be defined as an increase in proliferation which is seen when cells are allowed to attach to a solid surface. We have measured this increase by time-lapse cinematography and other methods, and have compared it with measurements of the change in surface area which also occurs. Anchorage dependence can be varied over very wide limits in cells of the NIL-8 hamster fibroblast line by varying the concentration of serum in the medium. Thus in a concentration of 5% serum, the transition probability (a measure of growth rate) of attached cells is 8 times greater than in suspension. When the serum concentration is raised to 66%, attached and suspended cells grow at the same rate. We have found that this change in growth is accompanied by a corresponding change in the exposed surface area of the cells. Thus in 5% serum, the area of attached is 3 times greater than suspended cells, while in 66% serum, the areas of attached and suspended cells are equal. There is also a significant relationship between the area and the total amount of growth achieved, since both suspended colonies and attached confluent monolayers appear to stop growing at the same surface: volume ratio. Several aspects of this relationship between anchorage dependence and area are also seen when other different types of cell are cultured in the suspended and attached state, all at the same serum concentration. These experiments show that change in exposed surface area can provide a complete explanation for the anchorage dependence of NIL-8 cells and suggest the possibility that this might also be true of animal cells in general.