The importance of Na+/H+ exchanger for the generation of procoagulant activity by porcine blood platelets.

This study addresses the role of the Na+/H+ exchanger (NHE) in the generation of procoagulant activity in blood platelets. It was found that monensin (simulating the action of NHE) and gramicidin (causing sodium influx without concomitant H+ efflux) produced a dose- and time-dependent increase in platelet procoagulant activity. Alkalinization of platelet cytosol by NH(4)Cl failed to evoke a procoagulant response. Collagen-induced procoagulant response was diminished in the absence of external Na+ and in the presence of EIPA (NHE inhibitor) or GF 109203X (protein kinase C inhibitor). Phorbol ester (PMA) produced a dose- and time-dependent generation of procoagulant response which was inhibited in the absence of the external Na+ and in the presence of EIPA. Platelets stimulated by collagen and PMA accumulated (22)Na+, a phenomenon inhibited in the presence of EIPA. The data indicate that development of procoagulant activity in platelets may occur as a result of Na+ influx via Na+/H+ exchanger.

Stimulation of arachidonic acid release from thyroid phospholipids.

The present study demonstrates that exposure of pig thyroid slices to thyrotropin stimulates the arachidonate release from endogenous phospholipids. The experiments with 14C-arachidonic acid show that the release of arachidonic acid is mostly from phosphatidylcholine, phosphatidylinositol and neutral lipids. The liberation of arachidonate from thyroid phospholipids is Ca2+ dependent. The addition of calcium ionophore A23187 to medium augments the release of arachidonate. Addition of ionophore and egzogenous Ca2+ markedly stimulates the arachidonate release, what suggests that thyroid phospholipase A2 can be regulated by the extend of saturation of the enzyme with Ca2+. The arachidonate release from phospholipids caused by thyrotropin is potentiated by adenosine. This effect shows that adenosine modulates TSH action and supports the idea that adenosine takes part in the physiological regulation of thyroid cells.

Effect of thyrotropin on phospholipid composition in thyroid plasma membranes.

Differences particular in phospholipid levels from pig thyroid membranes incubated in the presence of TSH were observed, but with exception of lysophosphatidylcholine, were not statistically significant. TSH evoked about a twice increase of lysophosphatidylcholine content. A slight decrease of phosphatidylcholine, phosphatidylinositol and phosphatidylserine were found, when at the same time a slight increase of phosphatidylethanolamine and sphingomyelin level was noted. There were no statistical differences in range fluctuation of individual phospholipid levels, but direction of fluctuation (i.e. decrease or increase) were identical for every single phospholipid in all experiments. An increase of lysophosphatidylcholine and a simultaneously decrease of phosphatidylcholine contents suggests the stimulation of phospholipase A2 activity.

Phospholipids of human thyroid gland.

The phospholipids from human thyroid have been identified and determined by two-dimensional chromatography. The total amount of lipid phosphorus was higher in pathological thyroids (especially in thyroid with Graves' disease) as compared to postmortem tissue. Insignificant differences in percentage distribution of phospholipids between normal tissue and from patients with Graves' disease and nodular goiter were noted. An increase of phosphatidylcholine and a decrease of phosphatidylinositol and sphingomyelin in pathological thyroids were observed. Physiological role of phospholipids in thyroid gland is discussed.

Stability and sorption of calcitriol in plastic tuberculin syringes.

The stability of commercially formulated calcitriol 1 and 2 micrograms/mL and calcitriol formulation subsequently diluted to 0.5 microgram/mL in 0.9% sodium chloride injection, 5% dextrose injection, or water for injection was evaluated after eight hours' storage in polypropylene syringes. The apparent affinities of calcitriol for polypropylene and polyvinyl chloride were also examined. Three calcitriol 0.5 microgram/mL solutions (diluted in 0.9% sodium chloride injection, 5% dextrose injection, or water for injection) and aqueous calcitriol formulations, 1 and 2 micrograms/mL, were placed in 1-mL polypropylene tuberculin syringes and assayed by high-performance liquid chromatography initially and after two, four, and eight hours' storage under room light at ambient temperature. Samples of calcitriol 2 micrograms/mL were also exposed to polypropylene or polyvinyl chloride at room temperature for 20 days. The remaining calcitriol concentrations were determined and apparent calcitriol polymer/water partition coefficients were calculated. Calcitriol concentrations did not change substantially during the eight-hour stability study. The mean apparent polymer/water partition coefficient for polyvinyl chloride was 66 times that for polypropylene, indicating that calcitriol has a definite affinity for polyvinyl chloride but no similar affinity for polypropylene. Aqueous calcitriol solution 1 or 2 micrograms/mL or 0.5 microgram/mL in 0.9% sodium chloride injection, 5% dextrose injection, or water for injection, when stored in polypropylene syringes exposed to ambient temperature and room light, appears to be stable for eight hours. Calcitriol appears to have greater affinity for polyvinyl chloride than for polypropylene.

[Thyroid gland inositol-1-phosphate synthase (its purification and characteristics)]. / Syntaza mio-inozytolo-1-fosforanowa z tarczycy (oczyszczanie i charakterystyka).

Pig thyroid myoinositol-phosphate synthase was purified about 30 times using ammonium sulphate fractionation and DEAE cellulose chromatography. The enzyme preparation showed the activity of more than 70 mU/mg of protein. A partially purified synthase is a very labile enzyme. Its activity showed optimum value at pH 7.0. This activity appeared to be controlled by NH4+, Na+, and Li+ ions. The biological role of thyroid synthase has been discussed.

Stability of various total nutrient admixture formulations using Liposyn II and Aminosyn II.

The compatibility of a safflower oil-soybean oil lipid emulsion (Liposyn II) with dextrose and amino acid injection (Aminosyn II) with or without electrolytes was studied in total nutrient admixtures (TNAs). The admixtures studied were divided into two groups. In group 1, 15 admixtures representing six different combinations of Liposyn II, Aminosyn II, and dextrose injection were studied. In group 2, nine admixtures representing nine combinations of Liposyn II, Aminosyn II with Electrolytes, and dextrose injection were studied. Both 10% and 20% concentrations of the fat emulsion, amino acid concentrations of 7, 8.5, and 10%, and dextrose injections of 10, 40, 50, and 70% were used. The core admixture components were placed in an ethylene vinyl acetate container in the following sequence: fat, amino acids, dextrose. One of two combinations of electrolytes and trace metals was added to each admixture at the end of mixing. Multivitamins were added to each TNA just before 24-hour storage at room temperature (25 +/- 4 degrees C). Four admixtures were tested after one day at room temperature, six after two days at 5 degrees C plus one day at 30 degrees C, and 14 after nine days at 5 degrees C plus one day at room temperature. Measurements of pH, emulsion particle size, and zeta potential (electrostatic surface charge of lipid particles) were made after visual inspection of each admixture. Concentration of individual amino acids and dextrose were determined by appropriate chromatographic techniques initially and at the end of the storage period. The TNAs retained a uniform, milk-like appearance under all storage conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Stability of total nutrient admixtures using various intravenous fat emulsions.

The stability of four lipid emulsions with amino acids and dextrose in total nutrient admixtures (TNAs) was studied. The admixtures were divided into three groups. In group 1, 24 admixtures representing 20 different combinations of Liposyn II (safflower oil-soybean oil fat emulsion) with various manufacturers' amino acids (FreAmine III, Travasol, Novamine, Nephramine, and RenAmin) were tested. In group 2, 19 TNAs representing 14 combinations containing soybean-oil emulsions (Intralipid, Travamulsion, and Soyacal) and Aminosyn II amino acids were studied. In group 3, 14 TNAs representing 9 combinations containing the above soybean oil emulsions and Aminosyn II with Electrolytes were tested. Both 10% and 20% concentrations of fat emulsion, various amino acid concentrations ranging from 5.4% to 11.4%, and dextrose injections of 10, 20, 40, 50, and 70% were used. The admixtures were compounded in an ethylene vinyl acetate container. The mixing sequence involved transfer of fat emulsion to the empty container, followed by amino acids and dextrose. One of two electrolyte and trace metal profiles was added to each core admixture after compounding. Multivitamins were added just before the 24-hour room-temperature (25 +/- 4 degrees C) storage. Admixtures were tested initially and after one day at room temperature or nine days at 5 degrees C plus one day at room-temperature storage. Measurements of pH, emulsion particle size, osmolality, and zeta potential (electrostatic surface charge of lipid particles) were made after visual inspection of each admixture. In general, the TNAs retained a uniform, milk-like appearance under both storage conditions. The values of pH, zeta potential, particle size, and osmolality remained essentially unchanged throughout the study. Under the conditions of this study, the TNA formulations tested are stable for up to 10 days.

Stability of Liposyn II fat emulsion in total nutrient admixtures.

Compatibility and safety of a safflower oil-soybean oil lipid emulsion (Liposyn II, Abbott) with amino acids and dextrose in total nutrient admixtures (TNAs) were studied. Sixty-two admixtures representing 31 different combinations of fat emulsion, amino acid injection, and dextrose injection were tested. Both 10% and 20% concentrations of the fat emulsion and three concentrations each of amino acid injection and dextrose injection were used; the core admixture components were placed in empty flexible plastic bags in three different sequences: fat, amino acids, dextrose; fat, then dextrose and amino acids simultaneously; and amino acids and dextrose simultaneously, then fat. One of two mixtures of electrolytes and trace metals was added to each sample at the end of mixing. Six samples were tested after one day at 25 degrees C, 35 after two days at 5 degrees C plus one day at 30 degrees C, and 21 after nine days at 5 degrees C plus one day at 25 degrees C. Multivitamin injections were added to each TNA just before the 24-hour room-temperature storage. pH, emulsion particle size, and zeta potential (electrostatic surface charge of lipid particles) were measured after visual inspection of each sample. Amino acids were separated by high-performance liquid chromatography and measured. Dextrose was measured by size-exclusion chromatography. In a controlled study of 24 dogs, six-hour infusions of TNAs containing Liposyn II 20% were administered for 14 days, after which all major organs and tissues were studied microscopically. At all storage times in the compatibility study, all TNAs retained a uniform, milk-like appearance.(ABSTRACT TRUNCATED AT 250 WORDS)

Activity of 5'-nucleotidase, AMP deaminase, adenosine deaminase, acid and alkaline phosphatase and nucleotide pyrophosphatase in human thyroid.

The activity of 5'-nucleotidase, AMP deaminase, adenosine deaminase, acid phosphatase, alkaline phosphatase and nucleotide pyrophosphatase was assayed in human thyroid glands. The 5'-nucleotidase activity was higher than that of AMP deaminase which suggested that AMP undergoes degradation primarily as a result of dephosphorylation in thyroid tissue. A high acid phosphatase activity was noted as compared to that of alkaline phosphatase activity. In toxic goitre the increase in adenosine deaminase and acid phosphatase was observed together with the decrease in pyrophosphatase activity.

Intracellular distribution of AMP deaminase in the pig thyroid gland.

AMP deaminase and adenosine deaminase activities were assayed in the subcellular fractions of pig thyroid gland. AMP deaminase is localized in the cytosolic fraction; however, this enzyme showed remarkable tendency to bind with the subcellular particulate fractions. Adenosine deaminase is also localized in the cytosolic fraction but in contradistinction to AMP deaminase, adenosine deaminase under the same experimental conditions has no tendency of binding to subcellular particulate fractions. The significance of AMP deaminase binding to subcellular particulate fractions is discussed.

Effect of iodide on glucose, N-acetylglucosamine and leucine incorporation into acid-insoluble fraction of pig thyroid proteins in vitro.

The effect of KI on D-[1-14C]glucose and N-acetyl-D-[1-14C]glucosamine incorporation into thyroid proteins was studied in vitro. It was found that KI in a concentration of 0.1 mmol 1-1 had no effect on the incorporation of the sugars under study. However, under the same experimental conditions KI inhibited L-[1-14C]leucine incorporation into proteins. It is suggested that KI, appropriate concentrations, inhibits the synthesis of peptide chains but has no effect on the incorporation of sugars into proteins.