The efficiency of energy transfer between a fluorescent donor, L-tyrosine, and a fluorescent acceptor, L-tryptophan, has been determined in R'-L-Trp-L-Ala-L-Tyr-R", R-L-Trp-L-Ala-L-Ala-L-Tyr-R", and R'-L-Trp-Gly-L-Ala-L-Tyr-R" in ethanol solution. The protecting groups R' and R" were respectively tert-butyloxycarbonyl and methyl ester. A conformational theoretical analysis of molecules studied has been performed in parallel on the basis of semiempirical conformational potential energy function. In the theoretical models all the side chains have been represented by a methyl group. From the distribution of distances between chromophores obtained theoretically, transfer efficiencies have been computed assuming a random orientation of the chromophores (k-2 equals 2/3). The comparison of calculated efficiencies with the values determined experimentally for the same value of k-2 has been used as a check for the theoretical model. Both experimental and theoretical studies have been shown that the glycyl residue procudes a reduction of dimensions when it replaces in a tetrapeptide a residue with a beta-carbon atom such as the L-alanyl residue. However, only a qualitative agreement between experimental and theoretical values of the efficiencies has been obtained.

Alanine↗

PubMedDate not supplied

Intermittent treatment with streptokinase in arterial disease of the limbs.

Sixty-two patients with arterial disease of the lower limbs were treated with streptokinase by intermittent administration. All patients had experienced recent aggravation of their arterial disease, and 22 had thrombolysis confirmed by arteriography. In 20 cases clinical study showed repermeation--in 8 cases during the first perfusion and in 8 cases during the third perfusion. During the first perfusion the fall in fibrinogen was significantly greater in the 8 patients with thrombolysis. Further, the third perfusion corresponded to a new phase of fibrinogenolysis. These results support the possibility of the relationship between plasminemia and thrombolysis, and emphasize the limits of the classic theory of Sherry, Fletcher, and Alkjaersig. Permitting phases of repeated but limited plasminemia, the interruption method used here is a compromise between the risk of hemorrhage and the efficacy of treatment at low dosage.

Angiography↗

PubMedDate not supplied

[Antithrombin III in 86 patients with venous thrombosis (author's transl)].

Antithrombin III concentration was studied in 86 patients with recurrent or extensive venous thrombosis. Two of them were found to have an hereditary antithrombin III deficiency. 25 patients receiving heparin therapy had low antithrombin III concentration. After stopping heparin treatment antithrombin rose to a normal level. Pathological antithrombin III modifications are recalled (synthesis decrease in liver diseases, intra vascular consumption during active venous thrombosis). Antithrombin III decreased activity induced by heparin treatment is pointed out.

Antithrombin III↗

PubMedDate not supplied

[Determination of the activity of plasma lactic dehydrogenase. Role of the leukocytes].

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Centrifugation↗