Ricin: the toxic protein of castor oil seeds.
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Biomedical subjects
Publications and source records attributed to G A Balint.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
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Artemisinin and its derivatives are a potent new class of antimalarials, originated from Artemisia annua, L. The clinical efficacy of these drugs is characterized by an almost immediate onset and rapid reduction of parasitaemia. Their efficacy is high in such areas as well where multidrug-resistance is rampant, but in these areas, their combination with other (effective) antimalarials (e.g., mefloquine) is highly recommended. In this short review, the chemical structures, pharmacological properties, and clinical uses of artemisinin drugs are discussed.
It is known that cAMP and cGMP, as an "intracellular second messenger system" play a significant role as a signal system, in the mechanism of action of anti-ulcerogenic (cytoprotective) drugs. According to our present, preliminary investigations it seems that during different experimental circumstances the gastric mucosal 3'-5'-cyclic-cytidine-mono-phosphate (cCMP) 3'-5'-cyclic-uridine-monophosphate and (cUMP) levels were changed--similarly to CAMP and cGMP--and these changes might be a possible indicator of a further, most probably secondary, signal- system role.
Homozygous Brattleboro rats were investigated and compared to normal (physiological) Wistar strain rats regarding their gastric mucosal endogenous prostacyclin (PG-I(2)) level. It seems that the Brattleboro animals have a significantly lower level of this important protective material. Wistar rats having an artificial pituitary stalk lesion (which is the artificial equivalent of homozygous Brattleboro animals) showed no differences in endogenous mucosal prostacyclin level compared to normal Wistar rats. Therefore, we concluded that this hitherto unknown property of the homozygous Brattleboro rats is genetically determined.
Graded single and multiple oral doses of prostacyclin enhance, in a direct dose-dependent manner, the DNA and RNA content of rat gastric (antral and fundic) mucosa, resulting in a decreased RNA/DNA ratio. This latter phenomenon is a convincing sign of new cell formation. The arithmetical (theory of functions) analysis of the data resulted in equations, defined mathematically, of prostacyclin's dose-dependent effect.