Perfluorocarbons as oxygen-transport fluids.

1. An overview of the proposed biological applications of perfluorocarbons and their emulsions as oxygen-transport fluids is presented. 2.

Lymphoid tissue responses to perfluorocarbon emulsion in mice.

The effects of either intraperitoneal or intravenous injection of low doses (5 or 10 ml/kg) of the proprietary emulsified perfluorocarbon-based blood substitute, Fluosol-DA 20%, on mouse lymphoid tissue and antibody production against sheep erythrocytes (SRBC) have been investigated. Mean liver weight was significantly increased and gut mesenteric lymph node (MLN) weights decreased in all animals injected with Fluosol-DA, irrespective of route of administration. In contrast, spleen weight decreased following intravenous injection of emulsion at 5 ml/kg.

Changes in plasma enzyme concentrations in response to blood substitution with perfluorocarbon emulsion in the conscious rat.

The effects of near total blood replacement with the proprietary perfluorocarbon (PFC)-based emulsion, Fluosol-DA 20%, on plasma concentrations of 2 enzymes, lactate dehydrogeanse (LDH) and alkaline phosphatase (ALP), have been examined in conscious, chronically catheterized rats. A pronounced fall in both plasma LDH (p less than 0.05) an ALP (p less than 0.

Oral immunization of mice with attenuated Salmonella enteritidis containing a recombinant plasmid which codes for production of the B subunit of heat-labile Escherichia coli enterotoxin.

We used Salmonella enteritidis serotype dublin strain SL1438, a nonreverting, aromatic-dependent, histidine-requiring mutant, as a recipient for a recombinant plasmid coding for production of the nontoxic B subunit of the heat-labile Escherichia coli enterotoxin. The S. enteritidis derivative EL23 produced heat-labile enterotoxin subunit B that was indistinguishable from heat-labile enterotoxin subunit B produced by strains of E.

Plasma growth hormone concentration in the chronically catheterized ovine fetus during spontaneous term delivery and premature delivery induced by continuous intravascular infusion of low doses of adrenocorticotropin or cortisol to the fetus.

Fetal plasma growth hormone concentrations were measured in 15 pregnant ewes over the last 5 days before delivery. In five chronically catheterized pregnant ewes that underwent spontaneous vaginal delivery 146 +/- 2 days (mean +/- SD) of gestation, fetal plasma growth hormone concentrations fell from 124.6 +/- 44.

Blood transfusion or blood substitution?

Blood transfusion has become a universally accepted, life-saving procedure in modern clinical medicine. In addition, specific blood fractions are widely used in the therapeutic treatment of haematological disorders. Problems are, however, encountered in conventional transfusion practice and in the clinical use of blood components.

Effects of a perfluorocarbon emulsion, Fluosol-DA, on rat lymphoid tissue and immunological competence.

The effects of administration of low doses (5 or 10 ml/kg body wt) of the proprietary perfluorocarbon emulsion blood substitute, Fluosol-DA 20%, on rat lymphoid tissue and antibody production against sheep red blood cells (SRBC) have been studied. Spleen and mesenteric lymph nodes (MLN) were significantly heavier at eight days after injection of Fluosol, whereas liver and thymus weights were unchanged. The mean plasma antibody titre to sheep red blood cells was significantly (P less than 0.

Changes in intravascular fluid composition following blood replacement with perfluorocarbon emulsion in the rat.

The effects of near total blood replacement with the proprietary perfluorocarbon emulsion, Fluosol-DA, have been examined in conscious, chronically catheterized rats. Animals survived for up to 48 h with a haematocrit of less than 2%. No overt changes in cardiovascular or respiratory functions occurred during blood replacement but thereafter, animals showed a progressive deterioration of haemodynamic control.

Intracellular distribution of heat-labile enterotoxin in a clinical isolate of Escherichia coli.

The intracellular distribution of heat-labile enterotoxin in a human isolate of enterotoxigenic Escherichia coli varied significantly as a result of changing incubation time, media, and degree of aeration. Direct comparison with a K-12 plasmid recipient revealed a similar but less dramatic response to environmental factors.

Comparison of changes in ovine plasma chorionic somatomammotropin concentrations in the fetus and mother before spontaneous vaginal delivery at term and adrenocorticotropin-induced premature delivery.

Fetal and maternal plasma ovine chorionic somatomammotropin concentrations have been measured in eight pregnant ewes immediately prior to spontaneous vaginal delivery at 146 +/- 2 gestational days. In seven additional ewes, fetal and maternal plasma ovine chorionic somatomammotropin concentrations were measured immediately before and during induction of premature delivery by infusion of 1 microgram X hr-1 synthetic adrenocorticotropin (ACTH1-24) to the fetus commencing at either 120 to 122 gestational days (n = 3) or 130 to 132 gestational days (n = 4). Both fetal and maternal plasma ovine chorionic somatomammotropin concentrations fell significantly (p less than 0.

Acute physiological responses during blood substitution with colloidal gelatin in conscious rats.

The effects of exchange-transfusion with a proprietary gelatin-based plasma volume expander, Haemaccel, have been investigated in conscious, chronically-catheterized rats. No adverse changes in basic cardiovascular or respiratory functions occurred during the procedure although an increase in intravascular fluid sodium but not potassium concentration was observed.

The effects of xylazine on uterine activity, fetal and maternal oxygenation, cardiovascular function, and fetal breathing.

Various pharmacologic agents used in the experimental study of physiologic processes may have pronounced effects on the systems under study. We have studied the effects of xylazine (Rompun) on myometrial activity, fetal and maternal pH, blood gases, heart rate, and fetal breathing movements in chronically catheterized fetal sheep. Xylazine is widely used as a premedication for various forms of animal operations, including the instrumentation of the chronically catheterized fetal sheep preparation.

In vivo SCE analysis using bromodeoxyuridine, iododeoxyuridine, and chlorodeoxyuridine.

Sister-chromatid exchange (SCE) frequencies were determined for mouse and rabbit bone-marrow cells following incorporation of 3 different halogenated analogues of thymidine. For both species the SCE frequency was highest for chlorodeoxyuridine, lowest for iododeoxyuridine and intermediate for bromodeoxyuridine. The study demonstrates that halogenated pyrimidine analogues other than brominated compounds can be used for in vivo SCE analysis and that their effects on baseline SCE frequencies are qualitatively similar to results of previous in vitro studies.

Acute responses during blood substitution in the conscious rat.

Changes in the cellular components of blood in response to exchange transfusion with the fluorocarbon emulsion blood substitute Fluosol-DA 20% have been examined in conscious chronically catheterized rats. Continuous isovolemic exchange transfusion at 1 ml X min-1 for 40 min reduced the mean haematocrit from 36% to less than 2%. The animals behaved normally during blood replacement and no significant changes in mean arterial blood pressure, heart rate or respiration rate were observed.

Fetal and adult hemoglobin in the chronically catheterized sheep fetus.

The switch from fetal to adult hemoglobin (Hb) has been investigated in fetal and newborn lambs. In the period between 125 and 145 days gestation, the proportion of fetal cells containing adult Hb increased significantly in catheterized fetuses. This increase paralleled the rise in fetal plasma cortisol under several different experimental conditions.

Changing patterns of steroid production in the fetus and placenta and their effects on development.

A variety of radioimmunoassays specifically characterized for use with fetal and maternal ovine plasma have been used to measure steroid hormone concentrations in small plasma samples drawn simultaneously from mother and fetus. By repeated sampling from the same animal preparation the changes over time of plasma concentrations of cortisol, pregnenolone and its sulphate, and oestrone and oestrone sulphate have been systematically studied. In animals delivering spontaneously at term the fetal plasma cortisol concentration rises between 120 and 130 days gestation and plays an important part in the maturation of several vital physiological systems, including the fetal thyroid axis.

Comparison of continuous transcutaneous and continuous intravascular PO2 measurement in fetal sheep.

Continuously monitored carotid arterial PO2 (PaO2) and transcutaneous PO2 (tcPO2) from the scalp of fetuses from ewes not in labor have been compared under epidural anesthesia at different levels of fetal oxygenation. A reasonably good correlation existed between the two readings at normal and high PO2 values. In sharp contrast, at low PaO2 levels there was a considerable bias between the two.