Biomedical subjects

C Tapparelli

Publications and source records attributed to C Tapparelli.

21 records · Page 2Linked to original sources

PubMed1986

Methylergometrine, an active metabolite of methysergide.

In conscious dogs methysergide (MS) caused constriction of the saphenous vein at about 3000 times lower doses than methylergometrine (MT) when infused locally, but it elicited only a short-lasting venoconstrictor response when injected systemically intravenously. MS and MT proved to be equally active venoconstrictor agents when administered orally. Analysis of canine plasma by high-performance liquid chromatography showed that after both oral and intravenous administration of MS large amounts of MT appeared in the plasma, whereas only low and transient levels of MS could be detected. It is suggested that one of the first steps in metabolism of MS is demethylation at position 1 of the indole, leading to the formation of MT, which may be a main active principle of the therapeutic effectiveness of MS in the interval treatment of migraine headache.

Administration, Oral↗

PubMed1986

Functional studies on human veins after storage at--190 degrees C.

Human saphenous veins were immersed in foetal calf serum containing 1.8 M dimethylsulphoxide, slowly frozen to -70 degrees C and stored in liquid nitrogen (-190 degrees C). Comparative in vitro studies on helical strips from unfrozen and frozen and thawed veins revealed that after thawing of frozen stored veins the contractile force development was unchanged, and the evidence suggested that the monoamine oxidase activity was unimpaired. There was a good correlation between the pD2 values of various 5-hydroxytryptamine receptor agonists and the blocking activities of various antagonists tested against 5-hydroxytryptamine (5-HT) and noradrenaline on unfrozen and frozen and thawed veins. It is suggested that cryopreservation is a useful technique for storing human veins for pharmacological studies.

Adrenergic alpha-Antagonists↗

PubMedDate not supplied

Cyclosporine A nephrotoxicity studied by the combined application of kidney cell lines, hepatocytes, and endothelial-platelet cocultures.

Established renal epithelial cell lines of human, pig, and dog origin (293, LLC-PK1, MDCK) were examined in terms of nephrotoxicity and ability to biotransform cyclosporine A (CsA). All three cell lines exhibited a comparable concentration dependent cytotoxicity to CsA treatment. Alterations in cell function included a decreased transport of lysine, an inhibition of growth, and an activation of lysosomal and mitochondrial activity as indicated by the increased uptake of neutral red (NR) and increased reduction of the tetrazolium dye MTT at 1-6 microM CsA. Increased leakage of lactic dehydrogenase and activities of gamma-glutamyl transpeptidase (GGT) and N-acetyl-beta-D-hexosaminidase were observed at 48 h and 12 microM CsA. A discrimination between CsA and the less nephrotoxic cyclosporine-(CsH) was shown for DNA synthesis and NR uptake. The contribution of extrarenal parameters on kidney cell function was studied by the addition of medium from hepatocytes exposed to CsA to the kidney cell lines. A more potent inhibition of DNA synthesis and enhanced reduction of MTT resulted than by addition of equimolar CsA directly to the kidney cells. These data indicate that hepatocyte constituents present in the medium due to CsA treatment affect kidney cell function; additionally, the presence of CsA metabolites may contribute to the CsA-induced nephrotoxicity. The vascular nephrotoxicity induced by CsA, an increased deposition of platelets in the renal arterioles, was mimicked by cocultures of endothelial cell monolayers and platelets. CsA increased the aggregability and adherence of platelets to the endothelial cell monolayers, whereas CsH had no effect.

Animals↗