Antigenic activity of lobster (Homarus vulgaris) arginine kinase and its cyanogen bromide fragments]

The antigenic saturation of lobster arginine kinase (38 000 daltons) by its specific antibodies has been studied. It was found that seven antigenic binding sites are simultaneously reactive on the surface of the enzyme in the presence of a large excess of antibodies or of their Fab fragments. After cyanogen bromide cleavage, the antigenic reactivity is distributed on several fragments of various sizes.     

Immunochemical characterization of antibody-coated nanoparticles

A new method using surface plasmon resonance (SPR) through the BIAcore was used to demonstrate the specific interaction between an anti-CD4 monoclonal antibody (IOT4a), adsorbed on poly(methylidene malonate 2.1.2) (PMM 2.1.2) nanoparticles, and the CD4 molecule. The results obtained were compared with the interaction of the same immunonanoparticles with rabbit anti-mouse Fc antibodies. The molar ratio (Fc)/(Fab) was 1, suggesting that the same number of epitopes on the Fc and the Fab fragments were accessible after IOT4a adsorption onto nanoparticles. Comparing the observed association rates of free antibody and antibody adsorbed on nanoparticles, the number of molecules of IOT4a antibody on PMM 2.1.2 nanoparticles was estimated as between 2.6 and 3 per nanoparticle. The properties of the antibody-coated nanoparticles are compatible with their use as antibody-targeted pharmacophores.     

Microméthode de dosage des anticorps antiallotype chez la Souris par un test de liaison avec le fragment Fc marqué à l'iode radioactif

Summary We describe a new binding test of anti-allotype antibodies anti-Igla from C 57 Bl/6 mouse serum with Fc fragments of CBA mouse IgG labelled with 131 (or 125) iodine. The precipitation of bound antibodies is achieved by rabbit anti-mouse Fab serum.

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L'auteur remercie le D^r N. A. Mitchison pour ses suggestions et pour l'hospitalité de son département.     

Anti-DNA antibodies: aspects of structure and pathogenicity

Anti-DNA antibodies contribute to the pathology of systemic lupus erythematosus. Their depositon in tissue lesions could result from localization of preformed immune complexes of antibodies with DNA or nucleosomes, or from cross-reaction of anti-DNA antibodies directly with tissue proteins. Structural analyses contribute to understanding their pathogenic potential. Primary structures of lupus immunoglobulin G double-stranded DNA-binding autoantibodies are determined by immunoglobulin genes with mutated variable region segments, indicative of selection by immunizing antigen. Arginine, lysine and asparagine residues in complementarity-determining region favor DNA binding. Heavy-chain variable regions make major contributions to DNA binding; affinity and specificity of binding are modulated or can be abrogated by the light-chain variable domain. Crytallographic structure is known for a few antibody-DNA complexes and several ligand-free Fab fragments. Computer modeling supplements this limited information. Structural information of lupus antibody interactions with both DNA and cross-reacting molecules will support use of ligands to inhibit tissue deposition of the antibodies and prevent lesion formation in lupus. Received 4 July 2002; accepted 23 July 2002 RID="*" ID="*"Corresponding author.     

An immunohistochemical study of the clearance of apoptotic cellular fragments

We investigated the distribution and fate of apoptotic bodies during human development and in the adult, using an antibody (M30) that recognizes a neo-epitope formed early in the apoptotic cascade by caspase cleavage of cytokeratin 18. In the fetus, we found extensive accumulation of M30-positive, non-phagocytosed fragments in the red pulp of the spleen, subcutaneous and submucosal vessels, the interstitium of the lung, and the glomerular mesangium of the kidneys. In the liver, M30-immunoreactive fragments were found inside macrophages in the sinusoids. The number of these fragments and the intensity of the immunostaining increased with the gestational age of the fetus. In the adult, M30-positive fragments were barely detectable in normal tissues. However, many pathological situations, including both chronic degenerative processes and metastatic cancer, were associated with accumulation of M30-positive fragments in the red pulp of the spleen. In the liver and kidney, no fragments could be detected. Remarkably, 13 of the 16 patients with metastasized cancer showed pronounced accumulation of M30-positive fragments containing hematoxylin-reactive material in the red pulp of the spleen. In the non-cancerous cases, such DNA-containing fragments were only seen in 9 of 94 cases. The results show that when apoptotic activity is high, as during development in the fetus or during metastasis and other pathological processes in the adult, the phagocytic clearance of apoptotic bodies can be overloaded. These apoptotic fragments then accumulate in the spleen. The visual detection of apoptotic fragments is concluded to reflect increased cell turnover. Received 1 July 2002; accepted 1 July 2002     

基于统计和未登录词碎片字典的未登录词识别方法

介绍了一种基于统计和未登录词碎片字典的未登录词识别方法。该方法首先在基于分词的基础上对一篇文本进行统计识别未登录词，然后利用来登录词碎片字典识别来登录词。实验结果表明：该方法较已有的来登录词识别方法曼适用于识别文本中不断涌现的新词，在未登录词的召回率和准确率性能指标上达到了较好的效果。     

Ultrastructural investigation of fetal rat brain hemisphere tissue in nonadherent stationary organ culture

Fetal rat brain fragments grown in nonadherent stationary organ culture for 50 days have been investigated ultrastructurally. Synaptogenesis and myelin formation occurred at the same time as the corresponding time-dependent events in the developing brain in vivo. Intermediate junctions were observed between cellular processes lining a central cavity in the fragments and later associated with astrocytes at the surface. Gap junctions and tight junctions were also present. In some fragments cilia were observed in the central cavity. Subependymal basement membrane labyrinths were observed in all fragments after 10 days in culture. The ultrastructural characteristics and the tissue-like structure in general were preserved for at least 50 days in this tissue culture system. The brain fragments may therefore be a valuable supplement to existing culture methods for nervous tissue.     

Ultrastructural investigation of fetal rat brain hemisphere tissue in nonadherent stationary organ culture

Summary Fetal rat brain fragments grown in nonadherent stationary organ culture for 50 days have been investigated ultrastructurally. Synaptogenesis and myelin formation occurred at the same time as the corresponding time-dependent events in the developing brain in vivo. Intermediate junctions were observed between cellular processes lining a central cavity in the fragments and later associated with astrocytes at the surface. Gap junctions and tight junctions were also present. In some fragments cilia were observed in the central cavity. Subependymal basement membrane labyrinths were observed in all fragments after 10 days in culture. The ultrastructural characteristics and the tissue-like structure in general were preserved for at least 50 days in this tissue culture system. The brain fragments may therefore be a valuable supplement to existing culture methods for nervous tissue.Research fellow from the Norwegian Research Council for Sciences and Humanities. This work was supported by the Norwegian Cancer Society.     

Cyanidin-3-β-glucoside,a newly recognized basis for resistance in cotton to the tobacco budwormheliothis virescens (Fab.) (lepidoptera: Noctuidae)

Summary Cyanidin-3--glucoside was shown to be an important factor of resistance in cottonGossypium hirsutum L. leaves to the tobacco budwormHeliothis virescens (Fab.). This provides a potential basis for achieving insect resistance in non-glanded cotton and other crops infested byHeliothis.In cooperation with the Mississippi Agriculture and Forestry Experiment Station, Mississippi State. Mention of a trademark, proprietary product or vendor does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products or vendors that may also be suitable.     

Cellular catabolism in apoptosis: DNA degradation and endonuclease activation

Recent research has focused on identifying the biochemical events associated with the apoptotic process. These include specific degradation of the chromatin which was described by Wyllie in 1980 [1], with the report of the appearance of discretely sized DNA fragments from apoptotic rat thymocytes. The fragments corresponded in size to strands of DNA that were cleaved at internucleosomal regions and create a ‘ladder patterns’ when electrophoresed on an agarose gel. Because of its near universality, internucleosomal DNA degradation is considered a diagnostic hallmark of cells undergoing apoptosis. It is of great interest to identify the enzymes involved, and some of the candidates will be discussed.     

Ultrastructural study of the glomerular filtration barrier and of tubular reabsorption with anti-peroxidase antibodies and their fragments]

Using anti-peroxidase Sheep IgG or their pepsic or papainic fragments intravenously injected to Wistar Munich normal Rats, the glomerular filtration barrier was localized at the lamina densa in ultrastructural studies. No evidence was found favoring the existence of a second barrier. The filtration barrier is absolute for the IgG but not for the pepsic and especially the papainic fragments which are reabsorbed by the proximal tubule.     

Complex formation betweenγ-immunoglobulin and calmodulin in calcium-free conditions

We show that -immunoglobulin (IgG) binds calmodulin (CaM) in a Ca²⁺-independent manner, with Kd value of (1.7±0.5)×10^–7M. A single IgG molecule maximally bound 10 CaM molecules. The binding is to the heavy chain or Fab portion, but not the Fc portion, of the IgG molecules. Ca²⁺ greatly diminished the interaction between IgG and CaM, with IC₅₀=8–9M. These data give a novel insight into protein-protein interactions.     

Successful cryopreservation of auricle fragments from rat hearts at −196°C

Summary The influence of electrolyte composition and glucose concentration of a cryprotective medium on the survival of auricle fragments from adult rat hearts after storage at –196°C was investigated. Using a K⁺-, Mg⁺⁺-, Ca⁺⁺-rich solution with increased glucose concentration, a high rate of surviving fragments was found after cryopreservation.     

Specific cleavage of insulin-like growth factor-binding protein-1 by a novel protease activity

Insulin-like growth factor-binding protein-1 (IGFBP-1) is secreted in a highly phosphorylated form that binds IGF-I with high affinity and is resistant to proteolysis. We have purified IGFBP-1-specific protease activity from the urine of an individual with multiple myeloma. This protease efficiently cleaves both phosphorylated and non-phosphorylated IGFBP-1 at Ile130-Ser131, generating fragments that together have higher association and dissociation rates for IGFs compared with intact IGFBP-1. The proteolytic fraction contained azurocidin, a protease homologue hitherto considered inactive. After cleavage of IGFBP-1, there was a lower affinity, but higher capacity for IGF-I binding, suggesting both N- and C-terminal fragments may interact with ligand independently. There was decreased inhibition of IGF-II-stimulated cell growth and glucose uptake. Alone, proteolysed IGFBP-1 stimulated glucose uptake in muscle. We conclude that specific cleavage of IGFBP-1 at target tissues is important in cellular growth and metabolism and opens novel strategies for targeting IGFBP-1 in treatment of disease.     

Étude électrophorétique concernant les protéines et les acides nucléiques tissulaires a propos de l'inhibition de la cancérogenèse

Summary Cancerous or leukotic tissue fragments modified by a 24 h subcutaneous implantation in the rabbit, become capable of favouring the inhibition of cancerogenesis.This paper is concerned with the study of proteins and nucleic acids of the so-treated implants.     

Primary tissue cultures from organ fragments: a simplified method.

Organ fragments washed in Ca++ and Mg++--free saline, treated with trypsin and placed directly into culture flasks adhered within seconds to the vessel surface. If the fragments were suspended in culture medium before they were added to the flasks, they did not adhere. This technique permits the rapid attachment and subsequent growth of the primary tissue cultures.     

Inhibition de la cancérogenèse spontanée chez les souris R III et AkR par des implants de tissus cancéreux modifiés

Summary (1) After a 24-h passage in a rabbit, fragments of spontaneous isologous mammary carcinoma were implanted under the skin of young R III females. This procedure was found to prevent the appearance of spontaneous mammary tumours in a high percentage of these animals. The subsequent appearance of carcinoma was to be observed in only 23% of treated animals as compared with 51% in controls.(2) After a 24-h passage in a rabbit, fragments of leukotic isologous tissue, implanted subcutaneously in young AkR females, reduced subsequent spontaneous leukomogenesis from 85 to 38%.     

Photolyse ultraviolette et photoréactivation des bactéries — Aspects de dépolymérisation et repolymérisation des acides nucléiques bactériens

Summary Electrophoretic analysis of bacterial substance proves the departure, from UV irradiated microbes screened from light for a certain time, of substances which were responsible for increasing the charge density by surface unit during the first moments which follow the irradiation by UV rays. Spectrophotometric analysis of liquids having contained these bacilli proves concommitantly the diffusion of those substances from the bacterial substance to the aqueous phase and reveals their nature. The photoreactivity which is possible during the first moments following the UV irradiation of bacilli, due to the presence of the fragments of depolymerisation of nucleic acid macromolecule in the bacterial substance, becomes impossible after the departure (diffusion) of those fragments to the aqueous phase. These observations seem to show that the phenomenon of photo-reactivity is connected with the repolymerisation of the macromolecule primitively divided of desoxyribonucleic acid.     

Degradation of ribosomal RNA from Escherichia coli by ribonuclease U2 and in vitro transcription of "RNA-fragments" into complementary DNA]

Under well defined conditions ribosomal RNAs purified from Escherichia coli can be degraded by ribonuclease U2 giving rise to RNA fragments of 60--70 nucleotides. In vitro, these fragments are efficiently transcribed into a complementary DNA by DNA polymerase RNA dependent, partially purified from extracts of E. coli. In vivo, "RNA-fragments-U2" inhibit the development of plant tumors.     

RNA fragments rich in G and A nucleotides obligatory for in vitro DNA replication of phages phi-X 174 and lambda]

Evidence was presented that in vitro conversion of single-stranded DNA of phage phi X 174 to the double-stranded replicative form by partially purified DNA-dependent DNA polymerase I requires a specific RNA fragment acting as primer (25-50 nucleotides). RNA fragments highly rich in nucleotides A and G were obtained by partial degradation of E. coli M 500 Sho-R ribosomal RNA with pancreatic ribonuclease. They become covalently bound to the newly synthesized DNA chain of the replicative form of phage phi X 174. These RNA fragments are also required for in vitro replication of lambda phage DNA.