A radioimmunoprecipitation method in the serodiagnosis of HIV infection: the development of the optimal conditions for its performance and the evaluation of the possibilities for its use

The optimum conditions for using the method of radioimmunoprecipitation (RIP) for the detection of human immunodeficiency virus (HIV) in serum samples have been established. Out of several available cell lines persistently infected with HIV, specially selected line 17 has been chosen. The characteristic feature of this is the high and stable (under the conditions of prolonged cultivation) accumulation of virus-specific proteins in infected cells. The optimum conditions for making the test and its evaluation have also been established. The data of literature on the advantages of the method of RIP over such traditional methods as the enzyme immunoassay and immunoblotting have been confirmed. Thus, the presence of specific antibodies in several serum samples registered as false negative has been established. The intertypical reactivity of two serotypes of the virus, HIV-1 and HIV-2, has been studied. Cross reactivity of antibodies with respect to the HIV gene gag, but not with respect to viral glycoproteids, has been established. Ideas on the expediency and prospects of using RIP for the serological control of HIV infection are presented.     

Isolation of monoclonal antibodies reacting with peribacteriod membranes and other components of pea root nodules containing Rhizobium leguminosarum

Plant and bacterial antigens contributing to nodule development and symbiosis in pea (Pisum sativum L.) roots were identified after isolation of a set of monoclonal antibody (McAb)-producing hybridoma lines. Rats were immunised with the peribacteriod material released by mild osmotic shock treatment from membrane-enclosed bacteroids of Rhizobium leguminosarum bv. viceae. In order to diversify the range of McAb specificities, this material was either used as immunogen directly (method 1), or after immunodepletion of a set of glycoprotein and lipopolysaccharide antigens (method 2), or after deglycosylation (method 3). After fusion and screening of cloned hybridoma lines, these three immunisation methods gave respectively 4, 2 and 1 classes of McAb with unique antigen specificities. Ultrastructural immunogold localisation studies showed four different antigens to be present on peribacteriod and plasma membranes (identified by MAC 64, 202, 206 or 209); in addition, a glycoprotein of plant origin but present in the infection-thread matrix was identified by MAC 204. Although none of the epitopes recognised by these McAb was nodule-specific, several were found to be more abundant in extracts of nodule tissue than in uninfected roots (MAC 64, 202, 204, 206). Two McAb reacted with new bacterial antigens: MAC 203 identified a bacterial antigen expressed upon infection but not in free-living cultures of Rhizobium, and MAC 115 identified a bacterial polypeptide (55 kdaltons) that was present in both free-living and bacteroid forms. There were also some McAb of broader specificity that react with antigens present in both plant and bacterial cytoplasms.Abbreviations ELISA enzyme-linked immunosorbent assay - Ig inmunoglobulin - kDa kilodalton - LPS lipopolysaccharide - McAb monoclonal antibody - PBM peribacteroid membrane - SDS-PAGE sodium dodecyl sulfate-polyacryl-amide gel electrophoresis - TFMS trifluoromethane sulfonic acid     

Oscillations in a collapsed-tube analog of the brachial artery under a sphygmomanometer cuff

To determine whether self-excited oscillations in a Starling resistor are relevant to physiological situations, a collapsible tube conveying an aqueous flow was externally pressurized along only a central segment of its unsupported length. This was achieved by passing the tube through a shorter and wider collapsible sleeve which was mounted in Starling resistor fashion in a pressure chamber. The tube size and material, and all other experimental parameters, were as used in our previous Starling resistor studies. Both low- and high-frequency self-excited oscillations were observed, but the low-frequency oscillations were sensitive to the sleeve type and length relative to unsupported distance. Pressure-flow characteristics showed multiple oscillatory modes, which differed quantitatively from those observed in comparable Starling resistors. Slow variation of driving pressure gave differing behavior according to whether the pressure was rising or falling, in accord with the hysteresis noted on the characteristics and in the tube law. The results are discussed in terms of the various possible mechanisms of collapsible tube instability, and reasons are presented for the absence of the low-frequency mode under most physiological circumstances.     

Book Reviews

Books reviewed in this article:
NICOTIANA: PROCEDURES FOR EXPERIMENTAL USE . Edited by R. D. D urbin
VIROIDS AND VIROID DISEASES . By T. O. D iener     

Studies on the role of cyclic guanosine 3':5'-monophosphate and extracellular Ca2+ in the regulation of glycogenolysis in rat liver cells.

Catecholamines increased guanosine 3':5'-monophosphate (cyclic GMP) accumulation by isolated rat liver cells. The increases in cyclic GMP due to 1.5 muM epinephrine, isoproterenol, or phenylephrine were blocked by phenoxybenzamine but not by propranolol. The possibility that cyclic GMP is involved in the glycogenolytic action of catecholamines seems unlikely since cyclic GMP accumulation is also elevated by carbachol, insulin, A23187, and to a lesser extent by glucagon. Furthermore, carbachol had little effect on glycogenolysis while insulin actually inhibited hepatic glycogenolysis. The rise in cyclic GMP due to carbachol was abolished by atropine and that due to all agents was markedly reduced by the omission of extracellular calcium. However, the glycogenolytic action of glucagon and catecholamines was only slightly inhibited by the omission of calcium. The only agent which was unable to stimulate glycogenolysis in calcium-free buffer was the divalent cation ionophore A23187. There was a drop in ATP content of liver cells during incubation in calcium-free buffer which was accompanied by an inhibition of glucagon-activated adenosine 3':5'-monophosphate (cyclic AMP) accumulation. The presence of calcium inhibited the rise in adenylate cyclase activity of lysed rat liver cells due to glucagon or isoproterenol but not that due to fluoride. These results suggest that the stimulation by catecholamines and glucagon of glycogenolysis is not mediated through cyclic GMP nor does it depend on the presence of extracellular calcium. Cyclic GMP accumulation was increased in liver cells by agents which either inhibit, have little affect, or accelerate glycogenolysis. The significance of elevations of cyclic GMP in rat liver cells remains to be established.     

The effect of isoproterenol and its analogs upon adenosine 3′,5′-monophosphate and guanosine 3′,5′-monophosphate levels in mouse parotid gland in vivo: Relationship to the stimulation of DNA synthesis

The ability of a large number of catecholamine analogs to stimulate DNA synthesis in the mouse parotid gland in vivo was compared to their effect on the levels of adenosine 3′,5′-monophosphate (cyclic AMP) and guanosine 3′,5′-monophosphate (cyclic GMP) in this tissue. In the normal parotid gland the level of cyclic GMP is very low (10^?9 moles/kg wet wt), being only 1/800th of the cyclic AMP concentration. Isoproterenol increases the levels of cyclic AMP and cyclic GMP 30- and 3-fold, respectively. The increase in cyclic AMP is biphasic with an apparent early maximum at 2.5 min and a main peak at 15 min while the increase in cyclic GMP is monophasic with maximum levels at 15 min. Other analogs showed a similar effect on cyclic AMP levels but the time course of increases in cyclic GMP was very variable with peak stimulation as early as 1 min in some cases. The ability of analogs to cause the accumulation of cyclic AMP was correlated with their capacity to activate adenylate cyclase in parotid extracts and to act as β-adrenergic agonists in other systems. All compounds which raised cyclic AMP levels stimulated DNA synthesis but a number of other analogs also stimulated DNA synthesis. The effects of these analogs have been correlated with their ability to raise the intracellular concentration of cyclic GMP. Cholinergic agents also cause the accumulation of cyclic GMP but the effect of the analogs does not appear to be mediated through the cholinergic system as atropine does not block their effects and cholinergic agonists do not stimulate DNA synthesis. It is suggested that cholinergic agonists and the catecholamine analogs act primarily on the duct and acinar cells, respectively.Significant with inhibitors of the rises in cyclic nucleotide levels suggest that in isoproterenol stimulation it is the rise in cyclic GMP which is the more significant event in relation to stimulation of DNA synthesis.