The inhibitory effects of respective DS and heparin on the fibrinogen-fibrin conversion were studied with purified bovine fibrinogen and thrombin as reagents.
1) Both DS (0.05-0.8mg/ml) and heparin (1.0-5.0u/ml) showed inhibitory effects on the whole fibrin polymerization. Further study was done at every step of all the reactions of fibrinogen-fibrin conversion.
2) The fibrinopeptide release which reflects the proteolysis of fibrinogen induced by thrombin was measured. Heparin inhibited the reaction, but DS didn't at this step.
3) Then both accelerated the fibrin monomer polymerization which reflects the reaction from fibrin monomer to fibrin.
These results showed that the fibrinogen-fibrin conversion was eventually inhibited by either DS or heparin, independent of AT III. The inhibition by heparin operated mainly at the step of thrombin-fibrinogen reaction, though fibrin monomer polymerization seemed to be accelerated later. While the inhibitory mechanisms by DS could not be clarified. These results also suggest that in coagulation studies with heparin or DS administered, there is a possible discrepancy between the anti-thrombin activities estimated by clotting time and those by chromogenic substrate.

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Four S-contained aminoacids (methionine, methyl-methionine, ethyl-methionine, and ethionine) were investigated in respect of their effects on prepared guinea-pig ilea. The results obtained are as follows:
1) Methionine initially induced an increase in intestinal tone and a decrease in amplitude. The increased tone recovered to its original level within 3 to 5 minutes and the amplitude also gradually recovered its original value. Thereafter, the tone, rate, and amplitude increased to a level slightly surpassing their original levels.
2) Methyl-methionine, ethyl-methionine, and ethionine at first induced a decrease in tone, rate, and amplitude, and after 3 to 5 minutes they recovered their original values. Methyl-methionine thereafter gradually increased them to a level slightly surpassing the original values, but ethyl-methionine and ethionine did not do so.
3) In the preparations from reserpinized guinea-pigs, the tone, rate, and amplitude decreasing effects of methyl-methionine were more remarkable than those in the normal preparations.
From these experimental results the following were concluded: the effects of these four agents consisted of diphasic effects, i. e., initial effects followed by subsequent effects. The initial effects may be those of the molecules of the drug and the subsequent effects may be those of the metabolites in the intestinal cells. The molecular effects of methionine and methyl-methionine are quite contrary, but their metabolite effects are qualitatively very similar. The latter effect of methionine is greater than that of methyl-methionine which may be changed to methionine in the intestinal tissue.
In gastric ulcer treatment, methyl-methionine may be used as an agent lacking the initial stimulation on the digestive tract produced by methionine, and its secondary promoting effect on tissue metabolism on the recovery process of gastric tissue damage may be caused by methionine as a metabolite of methyl-methionine.

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