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Biomedical subjects

H J Mest

Publications and source records attributed to H J Mest.

131 records · Page 8Linked to original sources
PubMedDate not supplied

The effects of locally applied PAF in inner ear morphology.

The effect of a PAF-containing artificial perilymph (10(-7) M PAF) on the ultrastructure of the stria vascularis was investigated in acute perilymphatic perfusion experiments in guinea-pigs. We have shown previously that locally applied PAF at this concentration reversibly changes the endolymphatic potential (EP) (Ernst et al., 1989a) which suggests an interference with ion transport. Controls which were perfused with artificial perilymph as well as experimental animals were decapitated at 10, 30 and 60 min after starting the perfusion. Subsequently, the cochleae were removed and evaluated by electron microscopy. The histological findings do not correspond to those obtained with different substances modifying ion transport in the stria vascularis, e.g., ouabain, loop diuretics. There are only minor strial changes in our study. The relevance of PAF in cochlear physiology is discussed.

Animals↗
PubMedDate not supplied

Antagonists of PAF and histamine inhibit ouabain-induced cardiac arrhythmias in sensitized guinea-pigs.

Platelet-activating factor (PAF) seems to be involved in different pathophysiological conditions, including cardiac arrhythmia. The arrhythmogenic potency of PAF has been shown experimentally by different methods. PAF antagonists inhibit the PAF-induced enhanced arrhythmogenicity. The present paper demonstrates that the threshold dose of ouabain-induced arrhythmia is decreased in sensitized guinea-pigs. Antagonists of PAF (BN 52021, WEB 2086, WEB 2170) and histamine antagonist clemastine can increase the threshold dose of ouabain-induced arrhythmia. A combination of WEB 2170 and clemastine, each of the drug is a low dose which is without effect when applying one of them only, shows a highly significant antiarrhythmic effect in this method. The threshold dose of ouabain necessary to induce ventricular flutter was increased from 89 micrograms/kg to 129 micrograms/kg and the threshold dose of ventricular fibrillation was enhanced from 101 micrograms/kg to 137 micrograms/kg. In dependence on the pathophysiological conditions, different mediators seem to be involved in the occurrence of cardiac arrhythmia. Therapeutically influencing these mediators could be a real chance to optimise the treatment of such kind of cardiac arrhythmias.

Anaphylaxis↗
PubMedDate not supplied

Local effects of PAF in guinea-pig inner ear.

The effect of PAF-containing artificial perilymph at 10(-7) and 10(-8) M on the endocochlear potential (EP) was investigated in guinea-pigs. The inner ear was perfused and the EP recorded at the same time. The characteristic decline of the EP which is highly sensitive to all stimuli could be prevented by pretreating the animals with either ginkgolide B (BN 52,021) or BM 13,177 (Sulotraban). Less effective in preventing the EP decline was Daltroban (BM 13,505). The results are discussed with respect to an involvement of PAF in cochlear physiology and in the regulation of ion transport, respectively.

Animals↗