PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 8349069

A multifunction and programmable computerized barostat.

T Hachet·M Caussette
View original source ↗Export metadata ↓

Abstract

A new computerized barostat allowing digestive tone measurement but also programmed distensions is described. The apparatus consists of a pump, driven by a computer, which injects or aspirates air in a flacid bag placed in a part of the gastrointestinal tract when relaxation or contraction occurs. Several parameters can be programmed for tone measurement: mean pressure, window pressure and air flow rate. Isovolumic or isobaric distensions can be performed using three modes: linear, stepwise or step by step with intermediate deflation. The height (mL or mmHg) of the steps and the duration of the distensions and the deflations can also be programmed. Three automatic and one manual safety systems are included. In comparison with previously described barostats the main feature of this apparatus is that it is entirely computerized and can be used for programmed distensions.

Explore related subjects

AtropineColonGastroenterologyHumansManometryMedical Informatics ComputingMuscle TonusStomachJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

T Hachet, M Caussette. 1993. A multifunction and programmable computerized barostat.. https://pubmed.ncbi.nlm.nih.gov/8349069/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1998

Characterization of muscarinic receptors in the human melanoma cell line SK-Mel-28 via calcium mobilization.

In melanoma cells of primary and metastatic human melanomas muscarinic cholinergic receptors are present. Muscarinic receptors were shown to be expressed in morphogenetically active embryonic cells. Therefore, the possibility exists that in melanomas an embryonic trait is re-expressed after transformation. In the present study, we demonstrated the presence of muscarinic receptors in the human melanoma cell line SK-Mel-28 by immunofluorescence with the monoclonal antibody M 35 and characterized the receptors further by measuring calcium mobilization after muscarinic stimulation. Cell suspensions were stained with fura-2 and fluorescence was followed at 380 nm excitation in a fluorimeter cuvette. After the addition of acetylcholine or carbachol a steep decrease in fluorescence intensity indicated calcium mobilization from intracellular stores (peak reaction), which was followed by a constantly lowered fluorescence level indicating a steady influx of extracellular calcium in the presence of agonist. By quantitative evaluation, dose-response curves were obtained from which an ED of 4.3 x 10(-6) M was calculated for acetylcholine and an ED of 2.2 x 10(-5) M was calculated for carbachol. After preincubation with antagonists the dose-response curve of acetylcholine was shifted to the right. The inhibition constant of pirenzepine was calculated as 3.9 x 10(-7) M, of methoctramine as 6.8 x 10(-7) M and of 4-DAMP-mustard as 1.9 X 10(-8) M. Comparison with the data from the literature and those obtained in the chick embryo indicates that the muscarinic receptor in SK-Mel-28 melanoma cells pharmacologically behaves as the M3 type and corresponds to the embryonic muscarinic receptor characterized by us in earlier studies.

Atropine↗
PubMed1998

The role and source of 5'-deoxyadenosyl radical in a carbon skeleton rearrangement catalyzed by a plant enzyme.

The last step in the biosynthesis of tropane alkaloids is the carbon skeleton rearrangement of littorine to hyoscyamine. The reaction is catalyzed by a cell-free extract prepared from cultured hairy roots of Datura stramonium. Adenosylmethionine stimulated the rearrangement 10-20-fold and showed saturation kinetics with an apparent Km of 25 microM. It is proposed that S-adenosylmethionine is the source of a 5'-deoxyadenosyl radical which initiates the rearrangement in a similar manner as it does in analogous rearrangements catalyzed by coenzyme B12-dependent enzymes. Possible roles of S-adenosylmethionine as a radical source in higher plants are discussed.

Atropine↗
PubMed1998

Cholinergic agonists increase intracellular Ca2+ in cultured human microglia.

Microglia are resident phagocytic cells in the central nervous system (CNS), and can be activated in response to various stimuli including neurotransmitters. Using fura-2 imaging, we investigated the effects of carbachol (CCh), a cholinergic agonist, on [Ca2+]i in cultured human microglia. Treatment of microglia with CCh (100 microM) produced a transient increase in [Ca2+]i, which was atropine-sensitive and was associated with release from intracellular Ca2+ stores. Successive applications of CCh showed a change in the amplitude of the [Ca2+]i signal consistent with desensitization. These results show that human microglia express functional muscarinic receptors and respond to cholinergic agonists. The rapid change of [Ca2+]i in microglia may serve as a second messenger to trigger downstream cascades which contribute to signalling pathways in CNS pathology.

Atropine↗