Die Wirkung des Toluidinblaus und der Thrombokinase auf den Vorgang der Thrombininaktivierung

Summary The disappearance of thrombin—formed in the blood, or added to serum-follows a manomolecular reaction-type. Heparin increases the reaction-velocity of this thrombin-inactivating process.Our investigation established that toluidine blue or kinase, which, according to the literature, bind heparin, strongly reduce the speed of thrombin-inactivation too. Therefore the heparin-binding capacity of these substances is also manifested in the decrease of thrombin-inactivation.     

Plant growth inhibitory lactones fromPodocarpus neriifolius: Structure of podolactone E

Résumé Le Podolactone E, qui a la structure (4), empêche très activement la croissance des cellules végétales. C'est le plus actif des podolactones isolés jusqu'à présent.     

X-ray diffraction of the collagen contained in blood vessels]

An X-ray diffraction study has been undertaken on Human and Rabbit blood-vessels. Vessels are stretched 500% and the diagrams present a great analogy with those obtained from collagen. Thus, it appears, that it is possible to determine by X-Rays some pathological anomalies of the collagen in vessels.     

Localized mutations in the gene encoding the cytoskeletal protein filamin A cause diverse malformations in humans

Remodeling of the cytoskeleton is central to the modulation of cell shape and migration. Filamin A, encoded by the gene FLNA, is a widely expressed protein that regulates re-organization of the actin cytoskeleton by interacting with integrins, transmembrane receptor complexes and second messengers. We identified localized mutations in FLNA that conserve the reading frame and lead to a broad range of congenital malformations, affecting craniofacial structures, skeleton, brain, viscera and urogenital tract, in four X-linked human disorders: otopalatodigital syndrome types 1 (OPD1; OMIM 311300) and 2 (OPD2; OMIM 304120), frontometaphyseal dysplasia (FMD; OMIM 305620) and Melnick-Needles syndrome (MNS; OMIM 309350). Several mutations are recurrent, and all are clustered into four regions of the gene: the actin-binding domain and rod domain repeats 3, 10 and 14/15. Our findings contrast with previous observations that loss of function of FLNA is embryonic lethal in males but manifests in females as a localized neuronal migration disorder, called periventricular nodular heterotopia (PVNH; refs. 3-6). The patterns of mutation, X-chromosome inactivation and phenotypic manifestations in the newly described mutations indicate that they have gain-of-function effects, implicating filamin A in signaling pathways that mediate organogenesis in multiple systems during embryonic development.     

Synaptic connectivity of a local circuit neurone in lateral geniculate nucleus of the cat

Although receptive fields of relay cells in the lateral geniculate nucleus of the cat nearly match those of their retinal afferents, only 10-20% of the synapses on these cells derive from the retina and are excitatory. Many more (30-40%) are inhibitory and largely control the gating of retinogeniculate transmission. These inhibitory synapses derive chiefly from two cell types: intrinsic local circuit neurones and cells in the adjacent perigeniculate nucleus. It has been difficult to study the functional organization of these inhibitory pathways; most efforts have relied on indirect approaches. Here we describe the use of direct techniques to study a local circuit neurone by iontophoresing horseradish peroxidase (HRP) into it, which completely labels the soma and processes of cells for subsequent light- and electron microscopic analysis. Although the response properties of the labelled cell are virtually indistinguishable from those of many relay cells, its morphology is typical of 'class 3' neurones (see Fig. 1 legend), which are widely believed to be interneurones (but see ref. 12). Here, we refer to the cell as a 'local circuit neurone', which allows for the possibility of a projection axon, rather than as an 'interneurone', a term that commonly excludes a projection axon. We find that the labelled cell has a myelinated axon, but that the axon loses its myelin within 50 microns of the soma and has not yet been traced further. The dendrites of the labelled cell possess presynaptic terminals that act as intrinsic sources of inhibition on geniculate relay cells. We also characterize other morphological aspects of this inhibitory circuitry.     

Side-chain hydroxylation in the biosynthesis of β-ecdysone (20-hydroxyecdysone) in the blowflyCalliphora stygia

Résumé Dans la mouche a viandeCalliphora stygia le 25-hydroxycholesterol et le (22R)-22-hydroxycholesterol sont incorporés a la -ecdysone (20-hydroxy-ecdysone) beaucoup moins qu'au cholesterol et ne sont donc probablement pas des précurseurs de cette hormone.