Search results for "Pigs"
showing 10 items of 331 documents
Papaverine decreases the efflux of42K in guinea-pig atrial heart muscle
1980
The effects of papaverine on resting potential and efflux of42K were investigated in guinea-pig left atria. Papaverine significantly reduced the potassium efflux in beating preparations. In resting preparations, the efflux of potassium was only slightly affected. However, the resting potential was significantly reduced by papaverine by about 5 mV.
Bacterial Cytolysin Perturbs Round Window Membrane Permeability Barrier In Vivo: Possible Cause of Sensorineural Hearing Loss in Acute Otitis Media
1998
ABSTRACT The passage of radioiodinated streptolysin-O (SLO) and albumin through the round window membrane (RWM) was studied in vivo. When applied to the middle ear, SLO became quantitatively entrapped in this compartment and no passage to the cochlea occurred. However, flux of radioiodinated albumin through the toxin-damaged RWM was observed. We propose that the passage of noxious macromolecules, such as proteases, from a purulent middle-ear effusion may be facilitated by pore-forming toxins, resulting in cochlear damage and sensorineural hearing loss.
Specific suppression of pentylenetetrazol-induced epileptiform discharges in CA3 neurons (hippocampal slice, guinea pig) by the organic calcium antag…
1989
Antiepileptic actions of the organic calcium antagonists flunarizine (cinnarizine derivate) and verapamil (papaverin derivat) on pentylenetetrazol-induced epileptic bioelectric activity were tested in CA3 neurones of hippocampal slices. In all experiments both calcium antagonists reduced the amplitudes and/or durations of paroxysmal depolarizations as well as their rate of occurrence, when the bath concentrations of flunarizine or verapamil exceeded 20 mumol/l. When they were added to the bath solution before pentylenetetrazol application, recordings of the resting membrane potential, of the membrane resistance, of action potentials and of spontaneous as well as of evoked excitatory and inh…
Evaluation of the in-vitro cidal activity and toxicity of a novel peroxygen biocide: 2-butanone peroxide
2007
The monomer of 2-butanone peroxide is a novel peroxygen derivative with potential use as biocide in the hospital environment. The aim of this study was to test the biocidal activity of different concentrations of the compound against American Tissue Culture Collection strains from 11 different micro-organisms, including bacteria, mycobacteria, spores, fungi and virus, following the European Standard guidelines. Toxicity tests were also carried out following United States Environmental Protection Agency Standards. 2-Butanone peroxide exhibited biocidal activity at 0.12% against Legionella pneumophila, at 0.5% against Escherichia coli, Pseudomonas aeruginosa and Enterococcus hirae, and at 1% …
Structure of the altitude adapted hemoglobin of Guinea pig in the R2-state
2010
Background: Guinea pigs are considered to be genetically adapted to a high altitude environment based on the consistent finding of a high oxygen affinity of their blood. Methodology/Principal Findings: The crystal structure of guinea pig hemoglobin at 1.8 A u resolution suggests that the increased oxygen affinity of guinea pig hemoglobin can be explained by two factors, namely a decreased stability of the Tstate and an increased stability of the R2-state. The destabilization of the T-state can be related to the substitution of a highly conserved proline (P44) to histidine (H44) in the a-subunit, which causes a steric hindrance with H97 of the b-subunit in the switch region. The stabilizatio…
Ultracytochemical localization of Ca2(+)-ATPase activity in the middle ear mucosa of the guinea pig.
1989
Ca2(+)-ATPase activity was studied ultra-cytochemically in the middle ear mucosa of the guinea pig. On electron microscopic examination, the most intense reaction was found on the microvilli. Reaction products were also observed on the cilia and around and between the secretory granules on the apical side of the cells in their secretory phase. The basolateral membranes contained few reaction products, while very little or no activity was found on the basal membrane.
Different intracellular cation-content present in right and left ventricle dependent on varying extracellular Ca2+-concentrations.
1979
Abstract The different intracellular cation-contents present in the right and left ventricle depend on varying Ca2+-concentrations. The effect of extracellular Ca2+-concentrations varied within the physiological range has been studied on an isolated guinea pig heart preparation, showing excellent stable experimental conditions. By increasing the extracellular Ca2+-concentration from 0.45 m m to 3.6 m m the tissue contents of calcium and potassium were increased dependent on [Ca]e whereas that of Na was reduced. This was due to a change in the composition of the intracellular cations as the extracellular space (inulin) and water-content of the heart muscle tissue were not influenced by incre…
COX-2 expression in the guinea pig cochlea is partly altered by moderate sound exposure.
2006
The cyclooxygenase-2 isoform (COX-2) was found recently to be constitutively expressed in the guinea pig inner ear. To gain knowledge about its role in sound perception, alterations in the COX-2 level of moderate noise-stimulated cochleae were determined. Staining intensities were quantified in different regions using an immunohistochemical staining procedure and computer-assisted system. After 70 dB and 90 dB noise exposure for 1 h at 8000 Hz, COX-2 downregulation was observed in the organ of Corti, which was most prominent in Deiters' cells near Hensen cells and outer hair cells. In pillar cells, COX-2 levels were only slightly reduced after 70 dB but strongly diminished after 90 dB expos…
Generation and release of eosinophil chemotactic factor from human polymorphonuclear neutrophils by arachidonic acid
1978
This study describes the generation and release of an eosinophil chemotactic factor from human polymorphonuclear neutrophils, rat basophilic leukemia cells, and from a lymphocyte monocyte basophil suspension by arachidonic acid (AA). The eosinophil chemotactic factor (ECF) is highly specific for eosinophils and resembles the ECF activity obtained from human polymorpho-nuclear neutrophils after stimulation with the Ca ionophore or during phagocytosis. In this regard, AA-induced ECF represents a biological activity distinct from oxidized AA and its conversion products. AA may therefore have a dual function: it represents an important mechanism of cell activation; as AA is converted into prost…
Immunoelectron-microscopic localization of synaptophysin in the organ of Corti of the guinea pig.
1997
Synaptophysin has been localized previously in the mammalian cochlea at the light-microscopic level and in few reports by electron microscopy using either a preincubation procedure or the avidin-biotin reaction. Here we present results of the electron-microscopic analysis for postembedding immunoreactivity of synaptophysin in the cochlea of the guinea pig of LR-White-embedded samples. Strong synaptophysin immunoreactivity is located in the cytoplasm of the efferent nerve endings at the base of inner and outer hair cells. Besides this, some antibodies to synaptophysin were also identified in the cytoplasm of outer hair cells. To get more information about the cellular content of synaptophysi…