Amoeboid movement: A review and proposal of a ‘membrane ratchet’ model

Summary Diverse cell types, including Amoebae, leukocytes, embryonic cells and tumour cells move about on solid surfaces to accomplish such activities as feeding, bacterial destruction, embryological development and metastasis. Theories of the mechanism of this movement are reviewed and a model is proposed which invokes the existence of specific, laterally mobile, transmembranous structures in the cell membrane, which are reversibly adhesive for both the contractile apparatus of the cell internally, and the substratum externally. By this model, the movement of all these cell types can be explained.     

Carbohydrate interference of complement-dependent cell lysis

Summary The antibody-mediated cytotoxicity of three autoreactive sera, an allogeneic hyperimmune serum and a xenogeneic hyperimmune serum was abrogated by the presence of either glucosamine, galactosamine, lactulose or lactose. This inhibition could be overcome in a dose-dependent fashion by increasing the amount of complement in the cytotoxicity assay, but not by increasing the amount of antibody. Furthermore, the inhibition was specific for these sugars in that isomers and N-acetylated derivatives were not inhibitory. The results suggest that these sugars directly blocked events of the complement cascade.     

Inhibition of sensitized leukocyte's in vitro reactivity by circulating immune complexes in prostate cancer

Summary Circulating immune complexes in the sera of patients with confirmed histological diagnosis of carcinoma of the prostate, were found to interfere in the sensitized leukocyte's in vitro reactivity to prostate cancer associated antigen as evaluated by tube leukocyte adherence inhibition assay, thereby suggesting an inhibitory role of such serum factors in host's anti tumor cell mediated immune responses.4 November 1986     

Cell-to-cell coupling studied in isolated ventricular cell pairs

Summary Cell pairs isolated from adult rat and guinea pig ventricles were used to study the electrical properties of the nexal membrane. Each cell of a pair was connected to a voltage-clamp system so as to enable whole-cell, tight-seal recording. The current-voltage relationship of the nexal membrane was found to be linear, revealing a resistance r_n of 2–4 M. r_n was insensitive to the sarcolemmal membrane potential (range:–90 to +30 mV), and exerted no time-dependent gating behavior (range: 0.1 to 10 s). Lowering pH_i yielded a small increase in r_n. Vigorous elevations in [Ca²⁺]_i gave rise to an increase in r_n which was associated with a cell shortening. Uncoupling caused by aliphatic alcohols or halothane did not produce cell shortening. Cell pairs were also used to study action potential transfer.     

Eicosapentaenoic acid in tissue lipids ofPieris brassicae

Summary Larvae of the cabbage white butterfly,Pieris brassicae, have a dietary requirement for linolenic acid (C183n3) and were found to accumulate two other members of the n-3 family, C203n3 and C205n3 (eicosapentaenoic acid) especially in testicular phospholipids. Arachidonic acid was observed in trace amounts only. During diapause the relative titer of eicosapentaenoic acid increased in testicular phospholipids to about 4.2% of the fatty acids. Eicosapentaenoic acid is a possible precursor of prostaglandins, suggesting that prostaglandins of the 3-series predominate in this insect.     

Hybridization histochemistry

Summary The location of gene expression by hybridization histochemistry is being applied in many areas of research and diagnosis. The aim of this technique is to detect specific mRNA in cells and tissues by hybridization with a complementary DNA or RNA probe. Requirements for optimal specificity, sensitivity, resolution and speed of detection may not all be encompassed in one simple technique suitable for all applications, thus appropriate procedures should be selected for specific objectives. With reference to published procedures and our own extensive experience, we have evaluated fixatives, probes, labels and other aspects of the technique critical to the preservation and hybridization in situ of mRNA and detection and quantition of hybrids.     

A new semisynthetic ergot peptide alkaloid: DCN 203-922

Summary We report the synthesis, stereochemistry and preliminary pharmacological evaluation of DCN 203-922, a novel ergot alkaloid of the cyclol type, which contains in its peptide moiety the uncommon amino acid L-allo-isoleucine.Part of this paper was reported by this author at the Herbstversammlung der Schweizerischen Chemischen Gesellschaft, Bern, in October 1986.     

Effect of glucose administration on bilirubin excretion in the rabbit

Summary The effect of i.v. infusion of glucose on the hepatic handling of bilirubin was examined in rabbits. A significant increase in the excretion of conjugated bilirubin into the bile was observed, accompanied by a decrease in bilirubinemia. Hepatic bilirubin concentrations were lowered and the UDP-glucose concentrations and liver UDP-glucuronosyl and UDP-glucosyl transferase activities increased.