Search PubMed⌕ Search

Biomedical subjects

J Parantainen

Publications and source records attributed to J Parantainen.

10 recordsLinked to original sources
PubMed1979

Tolfenamic acid is as effective as ergotamine during migraine attacks.

Tolfenamic acid (a potent inhibitor of prostaglandin biosynthesis), ergotamine tartrate, acetylsalicylic acid, or placebo was administered during 160 migraine attacks in twenty women in a double-blind, cross-over study. Tolfenamic acid and ergotamine were equally effective in reducing the duration and intensity of attacks, but side-effects, especially nausea, were less common with tolfenamic acid. This probably accounted for the patients' preference for tolfenamic acid. The effectiveness of tolfenamic acid in acute migraine attacks accords with the postulated role of prostaglandins in migraine.

Adolescent↗
PubMed1978

Effect of lowering of the temperature on the tissue levels of cAMP, cGMP, PGE and PGF2 alpha in spontaneously beating rat atria preparation.

Tissue levels of cAMP, cGMP, PGE, and PGF2 alpha were measured in spontaneously beating rat atria preparation at 20C and 37C. At 20C the formation of cAMP increased in correlation with the markedly increased amplitude and reduced frequency. The other biochemical parameters were not significantly affected by the low temperature.

Adaptation, Physiological↗
PubMed1978

Prostaglandins; their biological and pharmacological role.

The biological and pharmacological roles of prostaglandin system are reviewed. The most recent and important finding is the isolation and characterization of endoperoxides, thromboxanes and prostacyclin. In many respect they seem to be even more effective than the original prostaglandins and could explain many actions previously attributed to prostaglandins. Prostaglandins, endoperoxides, thromboxanes, and prostacyclin seem to have important physiological and pathophysiological roles, e.g. in the cardiovascular, gastro-intestinal and reproductive systems, the skin, and the central nervous system, as well as in inflammatory, immunological and metabolic reactions. Thus, prostaglandin-like substances, their analogues, prostaglandin antagonists, and the drugs that affect prostaglandin synthesis present good prospects for the treatment of many diseases affecting these systems. The mode of action of most anti-inflammatory and analgesic drugs can be explained by actions on the prostaglandin system. New potent and selective regulators of the prostaglandin system are being investigated and more indications are being found for using existing drugs. Although the field is generally promising, there are many contradictory findings. This calls for a cautious interpretation of the many interesting observations.

Animals↗
PubMed1978

The role of cyclic nucleotides and prostaglandins in heart function.

A short review of the role of cyclic nucleotides and prostaglandins (PGs) in normal and pathological functions of the heart is given. Possible interrelationships of these two regulatory systems have been studied by using spontaneously beating rat atria preparations. Addition of noradrenaline (NA) to the incubate (1 . 10(-6) M) caused an increase in amplitude and frequency which was preceded and parallelled by an elevation of the tissue cAMP level. A transient increase in cGMP and PGE values was also seen. Propranolol (5 . 10(-6) M) abolished the increase in amplitude and frequency as well as in cAMP and PGE concentrations. Indomethacin (1 . 10(-5) M) inhibited the formation of PGE. The increase in cGMP was blocked by phenoxybenzamine. Interchange between beta- and alpha-receptors according as the temperature is lowered has been described earlier. Hypothermia (20 degrees C) had a positive inotropic effect on the atria and increased the tissue cAMP concentration. Loading of the atria caused an increase in cAMP without any effects on cGMP or PGs. Slight hypoxia did not change the cAMP or PG levels, but elevated the cGMP values. Arrhythmias induced by hypo- or hyperpotassemia did not modify the biochemical parameters measured. PGF2alpha (1. 10(-5) M) normalized the atrial rhythm and increased the amplitude without changing cyclic nucleotide or PG levels. PGE1 (1 . 10(-4) M) increased the amplitude of normorhythmic atria and the tissue concentration of cAMP. PGE2 was the only PG tested which stimulated the heart adenylate cyclase in vitro. There seems to be close but complicated relationships between cyclic nucleotides and PGs in the heart.

Adenylyl Cyclases↗
PubMed1976

A sensitive biological assay for prostaglandin E and acetylcholine.

Superfused hamster stomach strip has been used in the bioassay of prostaglandin E2 (PGE2) and acetylcholine. The preparation proved very stable and had no spontaneous movements. The sensitivity to PGE2 (and PGE1) was in the range of 10(-9) g ml(-1) and to acetylcholine 10(-12) g ml(-1). After treatment with physostigmine the sensitivity to acetylcholine was 10(-15) g ml(-1). In acetylcholine determination the preparation is more sensitive than any other method.

Acetylcholine↗
PubMed1976

Inhibition of prostaglandin biosynthesis by tolfenamic acid in vitro.

The effect of tolfenamic acid on prostaglandin biosynthesis was investigated by using rabbit kidney medulla microsomal fraction, and the results compared with those obtained with indomethacin and acetylsalicylic acid. Tolfenamic acid inhibited the conversion of arachidonic acid to prostaglandin E2 very effectively and in a dose-dependent manner. IC50 values were 0.64 muM for tolfenamic acid, 0.76 muM for indomethacin, and 7 mM for acetylsalicylic acid. The inhibition of prostaglandin biosynthesis may be related to the good anti-inflammatory action of tolfenamic acid.

Animals↗