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(1) Lesions of the enteric nervous system and the possible role of mast cells in the pathogenic mechanisms of migration of schistosome eggs in the small intestine of cattle during Schistosoma bovis infection.[TOP]

Pubmed ID :10828512
Publication Date : //
The enteric nervous system in the small intestine of cattle during Schistosoma bovis infection was studied by histological stains and immunohistochemical methods. Lesions due to migration of schistosoma eggs were located mainly in the mucous and the submucous layer overlaying the submucous vascular arcades. Granulomas destroyed ganglia, neurons, nerves fibre strands and nerve fibres. Ganglia situated within or near granulomas were infiltrated by mast cells, eosinophils, lymphocytes, globule leukocytes, neutrophils and macrophages. Mast cells were in close contact with degenerating neuronal perikarya. Whereas vasoactive intestinal peptide-like immunoreactivity in the nerves and neurons in the ganglia within and around granulomas was increased, the neurofilament-like immunoreactivity was reduced. Compared to the myenteric and external submucous plexuses, the internal submucous and mucous plexuses were the most damaged. These changes imply reduced functional capacity in the nervous tissue which might cause reduced motility, malabsorption and partly account for the loss of body weight and condition and failure to thrive which occur in schistosomosis. Biotinylated affinity purified swine anti-rabbit and mouse anti-rabbit immunoglobulins reacted nonspecifically with a subset of mast cells. The reaction revealed many mast cells in early forming granulomas and around schistosome egg tracts and infiltration of mast cells into the ganglia of intestinal nerve plexuses. The observation shows a localized, Type I hypersensitivity reaction suggesting for the release of mast cell-derived chemical mediators in the intestinal reaction to trap or evict S. bovis eggs and to cause diarrhoea.

Authors : Balemba O B, Mbassa G K, Assey R J, Kahwa C K, Makundi A E, Hay-Schmidt A, Dantzer V, Semuguruka W D,

(2) VIP stimulation of beta-naphthylamidase activity in guinea-pig thyroid sections.[TOP]

Pubmed ID :4041109
Publication Date : //
Subsequent to the discovery of vasoactive intestinal peptide (VIP) in the thyroid gland, VIP has been shown to stimulate various thyroid functions. The site of interaction of VIP with the thyroid follicular cell is at present not known, and this study has used the ultrasensitive cytochemical bioassay (CBA) for thyroid stimulators to investigate this further. Exposure of thyroid sections for 3 min to VIP resulted in increased naphthylamidase activity, with half-maximal response observed at 3 X 10(-13) M VIP. This response to such low doses of VIP is consistent with the CBA being ultrasensitive to other thyroid stimulators e.g. TSH, thyroid stimulating antibodies and forskolin. The response to VIP was abolished by rabbit anti-VIP antiserum. The dose-response curve to VIP was bell-shaped (as with the other stimulators), maximal stimulation occurring at 10(-12) M VIP. In contrast, however, to other thyroid stimulators, namely TSH, LATS-B and 3 monoclonal stimulating antibodies, whose ascending limbs of the dose-response curves extended over 3-4 orders of magnitude, the VIP curve rose rapidly from basal to maximal tissue stimulation from 10(-13) to 10(-12) M VIP, i.e. one order of magnitude. This unusual dose-response curve to VIP was parallel to that produced by forskolin. 11E8, a monoclonal 'blocking' antibody which is a potent inhibitor of TSH stimulation, did not 'block' forskolin stimulation, consistent with the belief that forskolin acts at a post-receptor site.(ABSTRACT TRUNCATED AT 250 WORDS)

Authors : Ealey P A, Marshall N J, Ekins R P,

(3) Isolation and culture of endothelial cells from the lungs of small animals.[TOP]

Pubmed ID :222181
Publication Date : //
Techniques are descirbed for the isolation and culture of endothelial cells from the lungs of small animals. The cells are collected by retrograde perfusion of blood-free lungs with buffered saline containing collagenase. The cells are characterized by light microscopy, electron microscopy of thin sections and surface replicas, and by the presence of angiotensin-converting enzyme (ACE). ACE was assayed using 3H-benzoyl-Phe-Ala-Pro as substrate and was localized by indirect immunofluorescence using guinea pig endothelial cells incubated with rabbit antibodies to guinea pig lung ACE followed by goat anti-rabbit globulins conjugated to fluorescein. Thus, endothelial cultures can be established using small animals commonly employed in studies of pulmonary processing of vasoactive substances.

Authors : Habliston D L, Whitaker C, Hart M A, Ryan U S, Ryan J W,

(4) Immunological aspects of secretin, substance P, and VIP.[TOP]

Pubmed ID :838240
Publication Date : //
Secretin, substance P, and vasoactive intestinal peptide (VIP) were studied from the immunological point of view using synthetic hormones and their related peptides which were prepared by the conventional method for peptide synthesis. Immunological properties of these hormones were characterized by radioimmunoassays specific to the respective hormones. Antisecretin antisera (NCC-R-1 and R-801) were generated in rabbits with synthetic porcine secretin absorbed on polyvinylpyrrolidone. Antiserum to substance P (R-400) was produced in a rabbit with synthetic substance P-human alpha-globulin conjugate. Generation of anti-VIP antiserum (R-502) was carried out by immunizing rabbits with synthetic VIP absorbed on polyvinylpyrrolidone. Synthetic polypeptides related to the three hormones that were examined in this study include secretin(4-27), secretin(5-27), secretin(7-27), secretin(11-27), secretin(14-27), secretin(18-27), secretin(1-22)amide, secretin(7-22)amide, Nalpha-tyrosyl-secretin, [1-Tyr]secretin, [4-Ala]secretin, [4-D-Ala]secretin, [4-Ala,5-Val]secretin, [6-Tyr]secretin, substance P(2-11), substance P (3-11), substance P(4-11), substance P(5-11), substance P(6-11), Nalpha-tyrosyl-substance P, [1-Tyr]substance P, [8-Tyr]substance P, [11-Leu]substance P, des-11-Met-substance P, VIP(7-28), VIP(11-28), VIP(18-28), VIP(1-18)amide, and VIP(1-22)AMIDE. The results revealed two antigenic regions at the amino- and carboxylterminal portions of the secretin and VIP molecules. As to substance P, the major antigenic region was located within the 3 to 11 sequence. The proline residue in position 4 and methionine in position 11 seemed to be of special importance. The immunoassays demonstrated the existence of immunoreactivities of these hormones in hot water extracts from various porcine tissues. In the pituitary, VIP and substance P immunoreactivities were detected, whereas secretin was not. Secretin, VIP, and substance P were found in the pancreas, but at low concentrations. Distributions of these hormones in various sites of the gastrointestinal tract were also demonstrated.

Authors : Yanaihara N, Sakagami M, Sato H, Yammamoto K, Hashimoto T,

(5) The synthesis of bradykinin-azoprotein and its effectivity.[TOP]

Pubmed ID :69390
Publication Date : //
Some authors succeded in binding the bradykinin in form of a haptene by an azo-bridge to the human gammaglobulin as a vehicle. In this way, the bradykinin has been supplemented to a complete antigen. The bradykinin as a strongly vasoactive substance causes--after a local intradermal injection--an intensive circumscribed increase of the permeability of the capillaries. If such animals receive an intravenous or intracardiac injection of a 1% Evans blue solution, there is a strong blue colouring in the place where the bradykinin has been applied. The guinea pigs and the rabbits which had been immunized by bradykinin-azo-protein showed a significant decrease in the local accumulation of the Evans blue-solution,, which must be attributed to the immunologic neutralization of the intradermally injected bradykinin by an anti-bradykinin-antibody. The intradermally injected bradykinin is neutralized by the bradykinin-antibody. The intravenous or intracardiac injection of bradykinin causes a strong bronchoconstriction in the guinea pig. In those animals which have been pretreated with bradykinin-azo-protein, either there was no asthmatic dyspnoea at all or a decrease of the bronchial reaction would be found. This result very probably is also caused by the production and the activity of anti-bradykinin antibodies.

Authors : Filipp G, Lehmann G, Neunhoeffer O,

(6) Release of vasoactive substances from guinea-pig lungs by slow-reacting substance c and arachidonic acid. Its blockade by nonsteroid anti-inflammatory agents.[TOP]

Pubmed ID :4400351
Publication Date : //

Authors : Vargaftig B B, Dao N,

(7) The action of tyramine on the dog isolated atrium.[TOP]

Pubmed ID :13952141
Publication Date : //
It has been confirmed that tyramine has positive inotropic and chronotropic actions on the dog isolated atrium. These responses were incompletely and reversibly inhibited by cocaine, but completely and irreversibly blocked by phenoxybenzamine. Blockade of the atrial beta-receptors by dichloroisoprenaline could be overcome by noradrenaline and by larger doses of tyramine. With the aortic strip of the reserpinized rabbit for assay, tyramine was shown to release a vasoactive material from the dog atrium whose receptors were blocked by dichloroisoprenaline. The use of an antihistamine and an anti-5-hydroxytryptamine agent (cyproheptadine) appeared to exclude the possibility that the effect was due to the release of histamine or 5-hydroxytryptamine from the atrium by tyramine. Further observations of the action of the vasoactive material on the guinea-pig ileum and on the rat fundal strip strongly suggested that the material was a catechol amine. It was concluded that under these conditions tyramine acts by liberating catechol amines from storage sites so that the amines are free to act at receptor sites. The behaviour of the atrium to tyramine in the presence of cocaine or of phenoxybenzamine suggests that the liberation of catechol amines by tyramine differs from the release due to adrenergic nerve stimulation. It is suggested that, after an infusion of tyramine, there is a much slower release of catechol amines than after stimulation of adrenergic nerves.

Authors : HALL W J,