Interactions of interferon with other immunomodulators in the regulation of human natural killer cell activity]

The cytotoxic activity of natural killer (NK) cells isolated from peripheral blood of 20 healthy donors and 34 patients with multiple sclerosis (MS) against labelled with H3-uridine target cells K-562 before and after their 1 hr treatment with reaferon (RF), T-activin (TA), myelopid (MP), opioid preparation dalargin (DL) as well as with combinations of TA, MP and DL with RF was studied in 14 hrs cytotoxic test. It has been shown that combination of RF with TA, MP and DL changed the regulatory action of these peptides on NK cell activity in healthy donors in vitro. The same combination of the preparations in patients with MS caused another changes in regulation of NK activity by them because NK cells in MS patients had had initially changed sensitivity to action of these regulatory polypeptides.     

Effects of different doses of perfluorocarbon emulsion on hemodynamics and contractility of ischemic heart]

The effect of different doses of perfluorocarbon emulsion (5, 10, and 15 ml/kg) on the hemodynamics and contractility of heart was studied on anesthetized dogs. The emulsion was introduced intravenously by the 60th minute of acute myocardium ischemia caused by partial coronary occlusion. When pO2 = 120 mm Hg, the emulsion was efficient only at doses of 10 and 15 ml/kg (an increase in cardiac ejection, in the rate of contraction and relaxation of the myocardium, reduction of vascular resistance). However, the efficiency of the emulsion at a dose of 15 ml/kg was lower, possibly, due to hypervolemia and cardiodepressive effect of introduction of excess quantity of the surface-active substance proxanol, a component of the emulsion.     

Cyclic AMP efflux is regulated by occupancy of the adenosine receptor in pig aortic smooth muscle cells

Cultured pig aortic smooth muscle cells respond to extracellular adenosine by activating adenylate cyclase and by initiating the efflux of cAMP. In the presence of extracellular adenosine, efflux is first order with respect to intracellular cAMP concentration up to at least 125 pmol/10(6) cells. The apparent first-order rate constant for the efflux of cAMP increases in a dose-dependent manner in response to extracellular adenosine or 5-N-ethylcarboxamide adenosine. The EC50 for adenosine for promoting cAMP efflux is 12 microM. For cells stimulated with 5-N-ethylcarboxamide adenosine, the EC50 is 5 microM. When extracellular adenosine is removed, efflux stops abruptly. Cellular cAMP content falls but is still in a range that supports cAMP efflux when agonist is present. Efflux is not affected by H8 (N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride), an inhibitor of cAMP-dependent protein kinase. These data suggest that in pig aortic smooth muscle cells, the efficiency of cAMP efflux is regulated by A2 receptor occupancy.     

Rhinoplasty: the light reflexes

The physical characteristics of the light reflexes of the nasal tip are defined in large part by the studio lighting configuration. By varying the lighting configuration, it is possible to alter the light reflexes as regards their number, distance apart, symmetry, and size. For the plastic surgeon, the quarter light system of the medical photographer has definite advantages over the key light system of the portrait photographer. The quarter light system consists of two lights of equal intensity with symmetrical angles of incidence placed at 45 degrees to the camera-subject axis. Measuring changes in the light reflexes as a method of determining the efficacy of surgical techniques is valid under very controlled conditions.     

Stimulation of CTP: phosphocholine cytidylyltransferase and phosphatidylcholine synthesis by incubation of rat hepatocytes with phospholipase A2

The effect of phospholipase A2 treatment of rat hepatocytes on CTP: phosphocholine cytidylyltransferase and phosphatidylcholine synthesis was investigated. Cytidylyltransferase is recovered from the cytosol and in a membrane-bound form with the microsomes. Digitonin treatment of cells causes rapid release into the medium of the cytosolic, but not the microsomal form of the cytidylyltransferase. Incubation of hepatocytes for 10 min with phospholipase A2 (0.9 units/dish) in the medium, resulted in a 33% decrease in the cytidylyltransferase activity released by digitonin treatment (2.5 +/- 0.15 nmol/min per mg compared to 3.9 +/- 0.10 nmol/min per mg in the control). In agreement with the digitonin experiments, incubation with 0.9 units/dish of phospholipase A2 resulted in a decrease in the cytidylyltransferase activity in the cytosol (from 4.3 +/- 0.10 nmol/min per mg to 2.6 +/- 0.14 nmol/min per mg) and a corresponding increase in the microsomal fraction (from 0.9 +/- 0.16 nmol/min per mg to 1.8 +/- 0.20 nmol/min per mg). The effect of phospholipase A2 on cytidylyltransferase translocation was concentration- and time-dependent. Incubation of hepatocytes in the presence of phospholipase A2 (0.9 units/dish) for 10 min prior to pulse-chase experiments resulted in an increase in radiolabel incorporation into phosphatidylcholine (from 2.4 +/- 0.02.10(-5) dpm/dish to 3.1 +/- 0.1.10(-5) dpm/dish) and a corresponding decrease in radiolabel associated with the choline (from 2.5 +/- 0.05.10(-5) to 1.4 +/- 0.03.10(-5) dpm) and phosphocholine fractions (from 8.5 +/- 0.07.10(-5) to 6.9 +/- 0.05.10(-5) dpm). We conclude that phospholipase A2 can cause a stimulation of CTP: phosphocholine cytidylyltransferase activity and phosphatidylcholine synthesis in cultured rat hepatocytes.     

Composition of fatty acids and sphingosine bases of placental gangliosides

The fatty acids and sphingosine bases from major placenta gangliosides (NeuAcLacCer, IV3NeuAc-nLc4Cer, VI3NeuAc-nLc6Cer, (NeuAc)2LacCer, II3IV3(NeuAc)2Gg4Cer and VI3NeuAc, IV6(II3NeuAc-nLcNAc)-nLc6Cer) were studied. The C18-sphingenine was shown to be present in all ganglioside fractions; fraction GD1a contained, in addition, C20-sphingenine. Saturated fatty acids were identified as major fatty acid fragments. The content of long-chain acids (22-25 C-atoms) in the monosialogangliosides was much higher than that in disialogangliosides.     

Electrostatic forces at helix-coil boundaries in DNA

The Tm of internal loop-forming (dA.dT)N domains in pBR322 DNA has been measured over a tenfold range of [Na+]. The slopes SN = dTm/d log [Na+] are linear and decrease in magnitude with decreasing loop size N, signaling a reduction in Na+ released during the transition of these domains to the coil state. Values of SN decrease linearly with increasing N-1 in accordance with the expectation of a simple model for the occurrence of a gradient of long-range electrostatic forces at helix-coil boundaries, and extrapolate almost precisely to the value of S infinity observed for (dA.dT) infinity. These results indicate (1) less counterion is released per phosphate residue from the finite loop than from the infinite-sized loop, and (2) the difference in binding is constant for each boundary formed and independent of the size of the loop within the range examined: approximately 350 base pair (bp) greater than N greater than 71 bp. The slope of the dependence of SN on N-1 indicates the region of higher charge density at the boundary extends at least 18 A into the coil and probably 40-50 A before dropping to a value characteristic of the unperturbed coil. The free energy for excess counterion binding at boundaries can be expressed by -delta G/RT = 10.47 log[Na+] + 5.234 When the loop entropy function in a statistical mechanical algorithm for the dissociation of DNA is weighted by this quantity, calculated Tm are seen to vary by only +/- 0.09 degrees C from observed.