The structure of histargin.

The structure of histargin, an inhibitor of carboxypeptidase B, produced by Streptomyces roseoviridis MF118-A5 strain, has been defined as N-[(S)-1-carboxy-4-guanidinobutyl]-N'-[(S)-1-carboxy-2-(imidazol-4 -yl) ethyl]ethylenediamine, by spectral analysis and chemical synthesis.

Inhibition of brain prostaglandin D synthetase and prostaglandin D2 dehydrogenase by some saturated and unsaturated fatty acids.

The activities of rat brain prostaglandin D synthetase and swine brain prostaglandin D2 dehydrogenase were inhibited by some saturated and unsaturated fatty acids. Myristic acid was most potent among saturated straight-chain fatty acids so far tested. The IC50 values of this acid were 80 microM for prostaglandin D synthetase and 7 microM for prostaglandin D2 dehydrogenase, respectively.

Adenocarcinoma of the endometrium following prolonged use of an intrauterine device.

An Extremely rare case with the endometrial carcinoma induced by the prolonged (for 20 years) use of IUD (Oota Ring) was reported. The patient was a 57-year-old woman who visited our clinic claiming spotting, and the cancer was revealed by a D & C examination. Since no high risk factors for endometrial carcinogenesis were noted in this patient, it was inferred that prolonged use of IUD played an important role as a cocarcinogen.

Effect of heparin treatment in cases of severe toxemia.

Severe toxemia of pregnancy is associated with hypercoagulability and hyperlipemia in general. Heparin, a substance having an anticoagulant action and a lipemia-clearing action, was used clinically, and the changes induced by the heparin administration were examined. The GI value was significantly improved.

Inhibition of phenylalanine hydroxylase, a pterin-requiring monooxygenase, by oudenone and its derivatives.

Phenylalanine hydroxylase was shown to be inhibited by oudenone and its derivatives in vitro. At a concentration of 2.3 x 10(-3) M, oudenone inhibited phenylalanine hydroxylase by 50%, and some of the oudenone derivatives showed more potent inhibition.

Contribution of vagal tone to initiation and termination of ventricular tachycardia: report of three cases.

The role of vagus nerve in modulating ventricular dysrhythmia has recently been emphasized. We report here on two patients who had ventricular tachycardia (VT) which was terminated and converted to sinus rhythm by either eyeball pressure or a Valsalva maneuver. Moreover, in one of these patients and in a third patient, VT was initiated following administration of vagolytic agents.

2-Amino-5-methyl-5-hexenoic acid, a methionine analog produced by Streptomyces sp. MF374-C4.

2-Amino-5-methyl-5-hexenoic acid (AMHA), a new methionine analog, was isolated from a fermentation broth of Streptomyces sp. MF374-C4 based on its reversal of the effect of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in a test system that determines the size of growth zones of revertants (His+) of Salmonella typhimurium TA1535. AMHA also inhibited growth of the tester strain in a synthetic medium.

Supernormal responses to premature stimulation in Ca-dependent action potentials.

The responses of Ca-dependent action potentials to premature stimulation were studied in the isolated canine ventricular muscle. When very premature stimuli were applied, supernormally augmented responses with propagation occurred, while responses with long preceding intervals were small and not conducted.

The effect of hypoxia on the refractoriness of the canine ventricular muscle.

The effect of hypoxia on the relationship between refractoriness and transmembrane action potential was studied in isolated canine papillary muscle preparations. Test stimuli were applied at variable intervals after every 10 to 15 driving stimuli, and action potentials were recorded through an intracellular microelectrode located near the stimulus site. During hypoxia of 30 to 90 min duration, induced by nitrogenization of the perfusate, action potential duration (APD) was tremendously decreased in association with decline in the amplitude and rising velocity.

Dehydrodicaffeic acid dilactone, an inhibitor of catechol-O-methyl transferase.

In the screening of catechol-O-methyltransferase inhibitors, three compounds were isolated from the culture filtrate of a mushroom, Inonotus sp. One was 3,4-dihydroxycinnamic acid (caffeic acid) which had been reported as an inhibitor of this enzyme. The others were the dextrorotatory 2,6-bis-(3',4'-dihydroxyphenyl)-3,7-dioxabicyclo-[3,3,0]-octane 4,8-dione (dehydrodicaffeic acid dilactone) andits antipode.