Variations of cyclic nucleotide monophosphate levels during spontaneous uterine contractions.

Oscillations on the concentrations of cyclic nucliotides occurred during spontaneous rhythmic contractions in rat uterus. The levels of cyclic GMP and cyclic AMP were highest at the beginning of the contraction respectively the relaxation.     

Naloxone-reversible effect of opioids on pinocytosis in Amoeba proteus

A characteristic feature of induced pinocytosis in Amoeba proteus is the formation of broad channels by invagination of the cell membrane. This process, which requires Ca2+, occurs in response to depolarising cations. High Ca2+ levels reduce pinocytosis induced by cations such as Na+ and Tris+, whereas pinocytosis induced by K+ is less affected by Ca2+ (ref. 4). Agents which interfere with the calcium metabolism of the amoeba will therefore either stimulate or inhibit pinocytosis induced by Na+ (ref. 5). Among the agents which are supposed to reduce Ca2+ influx across cell membranes or otherwise decrease cellular availability of Ca2+ are the opiates and opioid peptides, high doses of which have been reported to affect the amoeba. Accordingly, Met-enkephalin, morphine and codeine potentiate the inhibition of pinocytosis caused by Ca2+-binding agents and reverse the calcium blockade of pinocytosis mediated by caffeine. In this report we show that pinocytosis induced by Na+ or Tris+ is suppressed by beta-endorphin, Metenkephalin and morphine. These effects were abolished or diminished by an opiate receptor antagonist, (-)naloxone, by increasing the Na+ concentration, or by addition of Ca2+.     

Immune electrophoretic analysis of bovine milk and purified bovine milk protein fractions

Zusammenfassung Immunoelektrophoretisch liessen sich aus Kuhmilch mit Hilfe einiger Kaninchen-Anti-Milchseren mindestens 12 Immunpräzipitate nachweisen. Von diesen waren 6 Präzipitate serologisch mit Blutserumproteinen verwandt (u. a. Albumin und-Globulin). Ferner wurden Präparate von-Kasein,-Laktoglobulin und-Laktalbumin analysiert.     

Spider silk proteins: recent advances in recombinant production,structure–function relationships and biomedical applications

Spider dragline silk is an outstanding material made up of unique proteins—spidroins. Analysis of the amino acid sequences of full-length spidroins reveals a tripartite composition: an N-terminal non-repetitive domain, a highly repetitive central part composed of approximately 100 polyalanine/glycine rich co-segments and a C-terminal non-repetitive domain. Recent molecular data on the terminal domains suggest that these have different functions. The composite nature of spidroins allows for recombinant production of individual and combined regions. Miniaturized spidroins designed by linking the terminal domains with a limited number of repetitive segments recapitulate the properties of native spidroins to a surprisingly large extent, provided that they are produced and isolated in a manner that retains water solubility until fibre formation is triggered. Biocompatibility studies in cell culture or in vivo of native and recombinant spider silk indicate that they are surprisingly well tolerated, suggesting that recombinant spider silk has potential for biomedical applications.     

Materials science. The hardest known oxide

A material as hard as diamond or cubic boron nitride has yet to be identified, but here we report the discovery of a cotunnite-structured titanium oxide which represents the hardest oxide known. This is a new polymorph of titanium dioxide, where titanium is nine-coordinated to oxygen in the cotunnite (PbCl2) structure. The phase is synthesized at pressures above 60 gigapascals (GPa) and temperatures above 1,000 K and is one of the least compressible and hardest polycrystalline materials to be described.     

MHC2TA is associated with differential MHC molecule expression and susceptibility to rheumatoid arthritis, multiple sclerosis and myocardial infarction

Antigen presentation to T cells by MHC molecules is essential for adaptive immune responses. To determine the exact position of a gene affecting expression of MHC molecules, we finely mapped a previously defined rat quantitative trait locus regulating MHC class II on microglia in an advanced intercross line. We identified a small interval including the gene MHC class II transactivator (Mhc2ta) and, using a map over six inbred strains combined with gene sequencing and expression analysis, two conserved Mhc2ta haplotypes segregating with MHC class II levels. In humans, a -168A --> G polymorphism in the type III promoter of the MHC class II transactivator (MHC2TA) was associated with increased susceptibility to rheumatoid arthritis, multiple sclerosis and myocardial infarction, as well as lower expression of MHC2TA after stimulation of leukocytes with interferon-gamma. We conclude that polymorphisms in Mhc2ta and MHC2TA result in differential MHC molecule expression and are associated with susceptibility to common complex diseases with inflammatory components.     

Matrix metalloproteinases in tumor invasion

Controlled degradation of extracellular matrix (ECM) is essential for the growth, invasion, and metastasis of malignant tumors, and for tumor-induced angiogenesis. Matrix metalloproteinases (MMPs) are a family of zinc-dependent neutral endopeptidases collectively capable of degrading essentially all ECM components and they apparently play an important role in all these aspects of tumor development. Furthermore, recent evidence suggests that MMPs also play a role in tumor cell survival. In this review, we discuss the current concept concerning the role of MMPs and their inhibitors in tumor invasion, as a basis for prognosis and targeted therapeutic intervention in cancer.