Role of serum components in the binding and phagocytosis of oxidatively damaged erythrocytes by autologous mouse macrophages

To investigate the role of autologous serum components in the recognition of damaged cells by macrophages, we examined the binding and phagocytosis of damage oxidatively damaged red blood cells with Cu2+ and ascorbate (oxRBCs) by autologous resident mouse peritoneal macrophages. The binding of oxRBCs by macrophages was independent of the presence of serum. However, phagocytosis by macrophages increased with serum concentration, and macrophages showed little ingestion of oxRBCs in a serum-free medium. Macrophages neither bound nor appreciably ingested native RBCs (before oxidation) in either the absence or presence of autologous serum. Mouse macrophages ingested significantly more native as well as oxRBCs in the presence of heat-inactivated fetal calf serum than in the presence of heat-inactivated mouse serum. Pretreated oxRBCs with normal serum were rarely ingested by macrophages in a serum-free medium. Phagocytosis of oxRBCs was significantly inhibited by depletion of IgG or calcium from serum, by heat inactivation of complement, or by antiserum against mouse C3. These results demonstrate that serum components such as IgG, C3, and calcium are involved in phagocytosis of oxRBCs by autologous macrophages.     

Inhibition of IgM antibody-mediated aggregation of Trypanosoma gambiense in the presence of complement.

This paper deals with the immune reaction between Trypanosoma gambiense and monoclonal IgM mouse antibody at equivalence with or without rabbit complement. Antibody-mediated trypanosome clumps formed in the absence of complement, and were readily dissociated by complement to become free. In the presence of complement, on the other hand, T. gambiense were not aggregated by the antibody. Free parasites adhered readily to cultured peritoneal macrophages. Complement-mediated dissociation of the clumped trypanosomes in the equivalence area released a large number of previously bound surface antigens. These antigens were capable of binding again to fresh IgM antibody. Experimental results further indicated that the complement system caused a functional alteration, changing the multivalent nature of the IgM antibody in the immune complex into a univalent one. This phenomenon is of great advantage to the infected host in clearing pathogens in vivo, as it allows more antibodies to attach to trypanosomes and subsequently initiate complement activity.     

Studies on the in vitro binding of D-penicillamine to cholestyramine

Summary Adsorption of D-penicillamine to cholestyramine depends on the amount of the resin, the pH and the presence of other compounds such as bile salts. In the usual drug to resin ratio (150 mg D-penicillamine and 4–8 g cholestyramine per single dose) the percentage of D-penicillamine adsorbed to cholestyramine was about 10% of the applied dose; Bile salts (10 mmoles/1) inhibited this small adsorption by 87%.     

Model of the interaction between trypsin and alpha 2-macroglobulin of porcine serum]

A comparative study of the dissociation into subunits of Porcine alpha2 M, either native or bound to trypsin (Tn), has been carried out in order to determine the modifications of the alpha2 M structure due to the formation of the Tn-alpha2 M complex. Analytical ultra-centrifugation at pH 3.5 shows that the dissociation is smaller when alpha 2 M is bound to trypsin. Electrophoresis in 4% polyacrylamide gels, in presence of 0.1% SDS, of alpha2 M and Tn-alpha2 M incubated in 1% SDS leads to the same conclusion; the enzyme must stabilize the quaternay structure of alpha2 M. In presence of SDS + beta-mercaptoethanol, only a molecular weight (M.W.) 200,000 band is revealed in electrophoresis pattern of native alpha2 M. In the case of reduced Tn-alpha2 M, some other bands of M.W. 100,000, 50,000, 30,000 appear. When trypsin is inactivated by TLCK 100,000 M.W. band is present, accompanied by the 200,000 M.W. band whose intensity is function of the alpha2 M concentration. The 100,000 M.W. band appears therefore characteristic of the formation of the complex which must imply a proteolytic cleavage in the middle of the 100,000 polypeptidic chain of alpha2 M. A model of the complex is proposed in which the enzyme forms a proteic bridge between the two halves of the alpha2 M molecule.     

Inhibition of IgM antibody-mediated aggregation ofTrypanosoma gambiense in the presence of complement

This paper deals with the immune reaction betweenTrypanosoma gambiense and monoclonal IgM mouse antibody at equivalence with or without rabbit complement. Antibody-mediated trypanosome clumps formed in the absence of complement, and were readily dissociated by complement to become free. In the presence of complement, on the other hand,T. gambiense were not aggregated by the antibody. Free parasites adhered readily to cultured peritoneal macrophages. Complement-mediated dissociation of the clumped trypanosomes in the equivalence area released a large number of previously bound surface antigens. These antigens were capable of binding again to fresh IgM antibody. Experimental results further indicated that the complement system caused a functional alteration, changing the multivalent nature of the IgM antibody in the immune complex into a univalent one. This phenomenon is of great advantage to the infected host in clearing pathogens in vivo, as it allows more antibodies to attach to trypanosomes and subsequently initiate complement activity.     

Regulation of antibody effector functions through IgG Fc N-glycosylation

Immunoglobulin gamma (IgG) antibodies are key effector proteins of the immune system. They recognize antigens with high specificity and are indispensable for immunological memory following pathogen exposure or vaccination. The constant, crystallizable fragment (Fc) of IgG molecules mediates antibody effector functions such as complement-dependent cytotoxicity, antibody-mediated cellular cytotoxicity, and antibody-dependent cell-mediated phagocytosis. These functions are regulated by a single N-linked, biantennary glycan of the heavy chain, which resides just below the hinge region, and the presence of specific sugar moieties on the glycan has profound implications on IgG effector functions. Emerging knowledge of how Fc glycans contribute to IgG structure and functions has opened new avenues for the therapeutic exploitation of defined antibody glycoforms in the treatment of cancer and autoimmune diseases. Here, we review recent advances in understanding proinflammatory IgG effector functions and their regulation by Fc glycans.     

Demonstration of dopaminergic receptors in human pituitary adenomas secreting prolactin]

3H Domperidone binding on cellular membranes from human prolactin adenomas demonstrates the presence of two dopaminergic binding sites. The mean value of the dissociation constant (Kd) for five adenomas is of 0.29 +/- 0.14 nM for the first site and of 4.19 +/- 1.56 nM for the second site. The maximal number of binding sites (Bmax) varies from one adenoma to another. The binding is completely displaced at 30 nM of tritiated Domperidone by apomorohine, a specific dopaminergic agonist.     

Extracellular wildtype and mutant SOD1 induces ER–Golgi pathology characteristic of amyotrophic lateral sclerosis in neuronal cells

Amyotrophic lateral sclerosis (ALS) is a fatal and rapidly progressing neurodegenerative disorder and the majority of ALS is sporadic, where misfolding and aggregation of Cu/Zn-superoxide dismutase (SOD1) is a feature shared with familial mutant-SOD1 cases. ALS is characterized by progressive neurospatial spread of pathology among motor neurons, and recently the transfer of extracellular, aggregated mutant SOD1 between cells was demonstrated in culture. However, there is currently no evidence that uptake of SOD1 into cells initiates neurodegenerative pathways reminiscent of ALS pathology. Similarly, whilst dysfunction to the ER–Golgi compartments is increasingly implicated in the pathogenesis of both sporadic and familial ALS, it remains unclear whether misfolded, wildtype SOD1 triggers ER–Golgi dysfunction. In this study we show that both extracellular, native wildtype and mutant SOD1 are taken up by macropinocytosis into neuronal cells. Hence uptake does not depend on SOD1 mutation or misfolding. We also demonstrate that purified mutant SOD1 added exogenously to neuronal cells inhibits protein transport between the ER–Golgi apparatus, leading to Golgi fragmentation, induction of ER stress and apoptotic cell death. Furthermore, we show that extracellular, aggregated, wildtype SOD1 also induces ER–Golgi pathology similar to mutant SOD1, leading to apoptotic cell death. Hence extracellular misfolded wildtype or mutant SOD1 induce dysfunction to ER–Golgi compartments characteristic of ALS in neuronal cells, implicating extracellular SOD1 in the spread of pathology among motor neurons in both sporadic and familial ALS.     

The action of D-penicillamine on cytochrome oxidase in vivo and in vitro

Summary The activity of cytochrome oxidase greatly decreases in the organs of rats treated with D-penicillamine for 20 days (30 mg/100 g/day). Although the drug does not affect cytochrome oxidase in vitro, it readily reduces oxidized cyt. c.     

Partial purification and some properties of a nucleoside phosphotransferase of chick embryos

Summary A nucleoside phosphotransferase purified about 40fold from chick embryos utilizes efficiently as phosphate donors deoxyribonucleoside and pyrimidine ribonucleoside monophosphates, whereas the pyrimidine deoxyribonucleoside appear to be the preferred acceptors of phosphate. The enzyme is very unstable to heat, dilution and dialysis. A marked enhancement in the stability is caused by nucleotides and it seems associated with the formation of an aggregated state of the protein.     

Effects of D-penicillamine on some oxidative enzymes of rat organs in vivo

Summary In the liver of neonate rats and in tissues of adult rats a study was made of the effect of D-penicillamine treatment in vivo on the enzymes of peroxide metabolism, lipid peroxidation and other components. It was found that D-penicillamine primarily acts by decreasing lipid peroxidation, thus stabilizing the membrane.Properties of enzymes. Serial publication Part XVI.Acknowledgment. We should like to take the opportunity to express our thanks to the Directorate of Knoll AG, Ludwigshafen. FRG, for the kind gift of Metalcaptase^®.     

Studies on the reconstitution ofP. clarkii blue carotenoprotein from its isolated subunits

Summary A blue carotenoid-protein complex (_max 635 nm) was extracted and purified from the carapace of the crayfishProcambarus clarkii. The complex was further liberated from astaxanthin, its prostetic group, causing dissociation into apoprotein subunits. Reconstitution of the complex from the various sub-units (isolated by chromatofocusing) plus astaxanthin was attempted. Apoprotein-size pigments of rose-purple color (_max 545 nm) were obtained. It was found that both monomers are required in order to a blue complex fairly similar in structure ot the native one. However, the native conformation was not completely recovered, as indicated by some differences in the UV spectrum.     

The sensitivity to plasmin digestion of human IgG proteins of different heavy chain subclasses.

Normal IgG and purified IgG proteins of all 4 subclasses were digested with plasmin. As expected, IgG3 proteins were highly susceptible to degradation. Usually, activation with streptokinase resulted in faster and more accentuated degradation, but normal IgG was more intensely degraded by nonactivated plasmin. The presence of plasmin activators in IgG preparation might account for this observation.     

宽带无线系统直接变频方式的设计与实现

为了进一步缩小宽带无线系统的体积、减小功耗,基于软件无线电的思想和专用的射频直接变频芯片,设计并实现了物理层直接变频方案。该方案使用MAX2831芯片实现射频与基带之间的直接变换,利用FPGA实现基带信号处理和射频模块的控制。详细讨论了方案的硬件结构和软件的设计方法,通过实验验证了直接变频前端的收发性能。实验结果表明,所设计的物理屡射频前端方案能够满足宽带无线通信的直接变频功能,且结构简单,便于工业应用。     

Inhibition of paraquat phytotoxicity by a novel copper chelate with superoxide dismutating activity.

A chelate with superoxide dismutase activity, D-penicillamine copper complex, was shown to inhibit paraquat toxicity in flax cotyledons (Linum usitatissimum var. Reina). Paraquat-stimulated chlorophyll loss and ethane production were markedly reduced by this complex. The role of superoxide in the action of paraquat is briefly discussed.     

Control of corpus allatum activity inDiploptera punctata: roles of the pars intercerebralis and pars lateralis

Summary Control of the corpora allata (CA) ofDiploptera punctata is maintained by at least 2 factors. The glands are directly inhibited by an allatostatin arriving at the CA via the nervi corporis cardiaci I (NCC I). Destruction of the putative source (median neurosecretory cells, MNC) of the allatostatin by radio-frequency (RF) cautery relieved the inhibition imposed on the CA of virgin females, and the glands became active. Similarly, destruction of the lateral neurosecretory cells (LNC) also relieved the inhibition. We propose that the LNC stimulated the MNC to release allatostatin. RF-cautery did not result in the activation of CA of pregnant or ovariectomized females. Activation of the CA may therefore require not only absence of the inhibitory factor but also the presence of a stimulatory one (perhaps from the ovary).     

Binding of cytophilic rabbit IgG to homologous hepatocytes.

Rabbit liver cells were able to bind cytophilic monomeric and polymeric homologous IgG via their Fc receptor binding sites (FcR). On the other hand, non-cytophilic rabbit IgG did not bind to hepatocytes, even after its aggregation. The present findings suggest that FcR on rabbit liver cells are specific for cytophilic monomeric IgG but do not significantly bind non-cytophilic, polymeric IgG.     

Forecasting temporally aggregated vector ARMA processes

If interest centres on forecasting a temporally aggregated multiple time series and the generation process of the disaggregate series is a known vector ARMA (autoregressive moving average) process then forecasting the disaggregate series and temporally aggregating the forecasts is at least as efficient, under a mean squared error measure, as forecasting the aggregated series directly. Necessary and sufficient conditions for equality of the two forecasts are given. In practice the data generation process is usually unknown and has to be determined from the available data. Using asymptotic theory it is shown that also in this case aggregated forecasts from the disaggregate process will usually be superior to forecasts obtained from the aggregated process.     

Selective killing of smooth muscle cells in culture by the ricin A-chain conjugated with monoclonal antibodies to a cell surface antigen via a dextran bridge

Monoclonal antibodies to a surface antigen of the modulated smooth muscle cells originally isolated from the rat aorta media were conjugated with ricin A-chain via an oxidized dextran bridge. The interaction of cultured cells with the conjugates obtained and with control substances was monitored following incorporation of 14C-leucine radioactivity. It was found that 14C-leucine incorporation was suppressed by 80-90% at a conjugate concentration of 10(-6)-10(-7) M. Antigen-negative cells (line IAR; rat hepatocytes) were insensitive to the conjugate at any concentration used. Control use of purified ricin A-chain, native or oxidized dextran, specific and nonspecific IgG did not affect normal 14C-leucine incorporation. The data obtained may be useful for designing targeted drug transport systems and for selective screening of modulated smooth cells in vascular pathology models in vivo.