2,201 research outputs found

    Pressure and protein denaturation

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    Kinetic analyses have indicated that moderate hydrostatic pressures, up to some 700 atmospheres, oppose reversible and irreversible denaturations of certain enzyme systems, apparent at temperatures above the normal optimum of the enzyme reaction, as well as at lower temperatures in the presence of denaturants such as alcohol (1-4). Qualitative observations have shown that such pressures also retard the precipitation of highly purified human serum globulin and egg albumin at 65° (5) and slow the destruction of specific antitoxic activity at the same temperature (6). In this study we have obtained quantitative data with regard to the influence of various pressures, up to 10,000 pounds per sq. in., and of low concentrations of ethyl alcohol on the time course of precipitation of human serum globulin (1) at 65° and pH 6.0

    The retention of S35-labelled bovine serum albumin on normal and immunized rabbit liver tissue

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    The S35-label of S35-BSA was detected in the liver tissue of rabbits to the extent of 0.02 per cent (10 µg or sime 1014 molecules) of the injected material at 140 days after injection. The rate of loss of antigen at the termination of the experiment was of such an order that significant amounts would be expected to persist for at least several years. Data are reported which extend the retention data previously reported on S35-labelled hemocyanin. They indicate that amounts of the order of 0.05 per cent (25 µg.) of antigen material persist at 330 days after injection. All of the radioactivity of material retained in the liver tissue 6 weeks after injection was immunologically related to the original S35-BSA antigen. Preliminary studies are reported which indicate that the retained antigen is bound to ribonucleic acid. A new method is described for the isolation of p-azophenylsulfonate bovine serum albumin from tissue extracts by means of a Dowex 2 adsorbent

    The biological activity of soluble antigen-antibody complexes: II. Physical properties of soluble complexes having skin-irritating activity

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    Previous work by Germuth and McKinnon (1), Trapani et al. (2), and ourselves (3) has established the fact that soluble antigen-antibody complexes formed in excess antigen can, (a) induce symptoms similar to anaphylaxis, (b) cause contraction of isolated smooth muscle from normal guinea pigs, and (c) increase the permeability of skin capillaries in a manner similar to that obtained in passive cutaneous anaphylaxis. These findings immediately raise many questions as to the fundamental mechanisms involved. For example, is the free antigen playing some role; is the toxicity dependent upon some change in the molecular structure of either antigen or antibody upon combination; is the complex itself toxic without any change in the molecular structure of the components; is the antigen-antibody ratio important; and, is complement involved? The work reported here involves a study of the possible role of free antigen and the nature of the complex. Some study was also made of untreated and decomplemented antiserums and, although there was no difference, this cannot rule out the possible participation of the test animal's (guinea pig's) own complement

    Competition of haptens

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    Groups of rabbits were injected with either bovine serum albumin, sheep red cell stroma, or keyhole limpet hemocyanin to which 2,4-dinitrophenyl and/or p-azophenyl arsonate groups had been coupled. Groups of animals received either doubly coupled antigen or an equivalent mixture of singly coupled antigens. Materials were injected intravenously as a solution or subcutaneously and intramuscularly in complete Freund's adjuvant. The presence of dinitrophenyl groups on the immunizing antigen could suppress, partially or completely, the antibody response to p-azophenyl arsonate when this hapten was located on the same molecule. Suppression was dependent on the ratio of haptenic groups on the molecule, appeared to be greatly affected by the method of immunization, and could be demonstrated in all three antigen systems. Partial suppression was manifested in decreased frequency and delayed appearance of the response as well as decreased maximal antibody titers. These findings appear irreconcilable with the possibility of direct clonal selection of antibody-producing cells by unprocessed antigen

    Qudit Colour Codes and Gauge Colour Codes in All Spatial Dimensions

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    Two-level quantum systems, qubits, are not the only basis for quantum computation. Advantages exist in using qudits, d-level quantum systems, as the basic carrier of quantum information. We show that color codes, a class of topological quantum codes with remarkable transversality properties, can be generalized to the qudit paradigm. In recent developments it was found that in three spatial dimensions a qubit color code can support a transversal non-Clifford gate, and that in higher spatial dimensions additional non-Clifford gates can be found, saturating Bravyi and K\"onig's bound [Phys. Rev. Lett. 110, 170503 (2013)]. Furthermore, by using gauge fixing techniques, an effective set of Clifford gates can be achieved, removing the need for state distillation. We show that the qudit color code can support the qudit analogues of these gates, and show that in higher spatial dimensions a color code can support a phase gate from higher levels of the Clifford hierarchy which can be proven to saturate Bravyi and K\"onig's bound in all but a finite number of special cases. The methodology used is a generalisation of Bravyi and Haah's method of triorthogonal matrices [Phys. Rev. A 86 052329 (2012)], which may be of independent interest. For completeness, we show explicitly that the qudit color codes generalize to gauge color codes, and share the many of the favorable properties of their qubit counterparts.Comment: Authors' final cop

    EFFECT OF SECONDARY INJECTIONS OF ANTIGEN UPON THE RETENTION IN LIVER OF A PRIMARY INJECTION

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    The retention of antigen in rabbit liver tissue, resulting from a primary intravenous injection, is influenced by immunization brought about by subsequent intravenous injections of the same antigen. In rabbits given a single primary intravenous injection of radioactive antigen, the retention of radioactivity in liver tissue, after a period of 21 days, was greater than when the primary injection was followed by secondary injections of the same, but non-radioactive antigen. The results were similar for both S35-azohemocyanin and S35-azo-bovine-serum-albumin, except the hemocyanin was retained to a greater extent than the albumin. There was very little if any correlation between the number of secondary injections and retention of the initial injection. Quantitative antibody nitrogen data, obtained for the serum of each rabbit showed, in general, an inverse relationship between circulating antibody and radioactivity retained, i.e. the higher the circulating antibody titer, the lower the retention of radioactivity in liver tissue. Passively administered homologous antibody did not produce a change in the retention of the primary injection of antigen nor did secondary injections of a heterologous native protein injected according to the same immunization schedule as the homologous azoprotein. From these results it may be concluded that an intracellular antibody-forming activity influences the loss (or retention) of antigen deposited in liver tissue and that the mechanism is immunologically specific

    URINARY EXCRETION OF FOREIGN ANTIGENS AND RNA FOLLOWING PRIMARY AND SECONDARY INJECTIONS OF ANTIGENS

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    Two soluble antigens, BSA and KLH labeled with sulfanilate-35S, when injected intravenously into normal animals, were excreted in the urine to over 70% in 24 hr. Over the next 6 days, 25% more was excreted after which time only a trace could be detected. Much of the antigen remaining from the primary injection appeared in the urine following a secondary injection of the unlabeled protein carrier at 7 days after primary injection. The antigen material found in the urine was quite heterogeneous with respect to physical properties and much of it was associated with RNA material as shown by chromatographic analyses. The main difference between the labeled material released following the primary and secondary injection was the higher degree of association of antigen material with nucleotide material after secondary injection as compared with primary injection. Further study is needed to distinguish qualitative from quantitative changes of the components, antigen and nucleic acid, and also the nature of their association. Possible similarities were found for the RNA-antigen material released from tissue after secondary injection of unlabeled antigen, and the material that was isolated previously from liver
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