Rhône-Poulenc

About: Rhône-Poulenc is a based out in . It is known for research contribution in the topics: Alkyl & Catalysis. The organization has 8909 authors who have published 8934 publications receiving 182241 citations. The organization is also known as: Rhone-Poulenc.

A role for capsaicin sensitive, tachykinin containing nerves in chronic coughing and sneezing but not in asthma: a hypothesis.

Abstract: Sensory nerves with endings in the airway mucosa mediate respiratory protective reflexes such as coughing, sneezing, mucus secretion, and bronchoconstriction, which are common symptoms of airway disease. Studies in experimental animals suggest that these reflexes have unique afferent pathways, though these have been difficult to identify in man. One pharmacological tool that is increasingly used in studies of neural reflexes is capsaicin, the pungent agent of hot peppers. Capsaicin seems to excite rather selectively a population of tachykinin peptide containing, chemosensitive afferent nerves.' 2 In rodent airways capsaicin produces severe bronchoconstriction and a pronounced inflammatory response, which seems to be mediated by substance P, neurokinin A, and possibly other tachykinin peptides.36 Tachykinins contract human bronchi in vitro78 and produce bronchoconstriction when inhaled by asthmatic subjects.9 The density of substance P immunoreactive nerves'0 and expression of the neurokinin, receptor gene\" have been reported to be increased in the asthmatic lung. Consequently neuropeptide release, via an axon reflex, has been proposed to be particularly important in the pathology of asthma.'2 The proinflammatory effects so apparent in rodents, however, cannot be reproduced even when high doses of capsaicin are repeatedly inhaled by normal or asthmatic subjects6 and capsaicin sensitive nerves seem unlikely therefore to have a major role in asthma. Instead, experimental and clinical data indicate that their most important function in the human respiratory tract is to mediate protective reflexes. The hypothesis now is that hyperreactivity in these afferent nerves-that is, sensory hyperresponsiveness-contributes to respiratory symptoms in patients with chronic non-productive cough and nonallergic chronic rhinitis. genes.'5 These tachykinins, and calcitonin gene related peptide, are present in a population of non-myelinated capsaicin sensitive afferent nerves.5 Capsaicin induced neuropeptide release is preceded by increased cation permeability over the cell membrane. In larger concentrations capsaicin is neurotoxic and rapidly causes death of nerve cells. The tachykinins act on neurokinin 1,2, or 3 receptors (which have highest affinity for substance P, neurokinin A, and neurokinin B, respectively), located on airway and vascular smooth muscle, submucosal glands, parasympathetic nerves, and airway epithelium.\"6 In guinea pigs and rats tachykinin peptides produce bronchoconstriction, vasodilatation, plasma protein leakage from the tracheobronchial microcirculation, mucus secretion, and facilitation of cholinergic neurotransmission.'6 These effects are mimicked by capsaicin, suggesting an important sensory efferent role for these nerves. Thus in rodent airways neuropeptides released from capsaicin sensitive sensory neurones, presumably via an axon reflex,'7 have pronounced bronchoconstrictor and proinflammatory actions. Interestingly, the most obvious responses to intravascular administration of tachykinins or capsaicin in the sheep,'8 pig,'9 dog,20 and cat2l are a vasodilator response in the tracheobronchial circulation and mucus secretion.22 When present, airway smooth muscle contraction in rat, rabbit, ferret, and dog is largely mediated through parasympathetic cholinergic pathways.6 In the cat capsaicin produces a reflex bronchodi2atation. Furthermore, plasma protein extravasation has not been observed in cat or dog airways.24 Hence the characteristic bronchoconstrictor and proinflammatory effects have not been confirmed in non-rodent animal species.

European project for the development of high T/sub C/ current leads

Abstract: A European BRITE/EURAM project for the development of current leads in the kA range using high-T/sub C/ superconductor parts has been started recently. The partners in this two-year project are two chemical companies, Hoechst and Rhone-Poulenc, and two companies in the field of electrical engineering, Siemens and Alcatel Alsthom. The goal of these four companies is to develop current leads for 4.2-K systems making use of high-T/sub C/ superconducting materials, to manufacture them, to demonstrate their performance in comparison with conventional all-metal current lead, and to develop relevant models. The objective is the realization of a demonstration current lead toward the end of the project. This device will operate at a steady-state current of 1000 A and an insulation voltage of 20 kV. The losses will be reduced to one-third of the losses of a conventional metallic current lead. First results are given on Y- and Bi-based current lead models, including calculations and the characterization of large bulk high-T/sub C/ samples up to a length of 200 mm with a I/sub C/ value reaching 2000 A. >

Modified hydrophobic cationic thickening compositions

Abstract: Water soluble quaternary ammonium ethers of polysaccharides or polyols wherein the quaternary ammonium ether substituents correspond to the formula ##STR1## wherein R 1 is a monohydroxylated or polyhydroxylated alkyl group containing between about one and about six carbon atoms; R 2 and R 3 are independently, alkyl groups containing between about one and about six carbon atoms; R 4 is an alkyl group containing between about six and about 24 carbon atoms; and X is a halide, wherein the degree of substitution of said ethers ranges from about 0.001 to about 0.5. is provided. The composition have multiple uses as thickeners and are particularly suited for use in personal care products.