[The application of argon plasma coagulation in thoracic surgery: principles, surgical technique and clinical results]. / Prilozhenie na argon-plazmena koagulatsiia v grudnata khirurgiia--printsipi, operativna tekhnima, klinichni rezultati.

BACKGROUND: In recent years, together with the well-known high-frequency electro-coagulation, the application of plasma coagulation has been also introduced in the clinical practice. The argon plasma coagulator (APC) is one of the representatives of this surgical technique. By its nature, the APC represents a non-contact electrothermal tissue coagulation, combining the principle of the augmented surface and enhanced autogenous haemostatic mechanisms. AIM: The main objective of this study was to evaluate whether APC is an effective and safe modality in the open pulmonary surgery. MATERIALS AND METHODS: For the period from 01.01.2003 to 30.01.2004 year, in the Clinic of Thoracic Surgery, we have applied the technique of APC to 15 patients. The distribution by sex was: 10 males and 5 females. According to the nosological units, the distribution was as follows: pulmonary carcinoma in 3, pulmonary echinococcosis in 4, pleural empyema in 6, pulmonary abscessus in 1 and esophageal ahalasia in 1 patient. In our practice, we have used an argon plasma coagulator of BERCHTOLD GmbH. A power setting of 20W with exposition time 15 s and an argon gas flow setting of 1,5-2 1/h have been used in our series. Energy dose applied in our patients didn't exceed 300 J/cm2. RESULTS: The results we have obtained demonstrate the following fundamental advantages of APC: a possibility to work with long electrode--tissue distance; a possibility for large surface coagulation as well as coagulation under variable angle, limited and well controlled depth of penetration, substantial reduction of carbonization; regular distribution of the energy over the whole coagulating surface, a possibility to treat effectively larger bleeding surfaces. CONCLUSIONS: Although initial, our experience gives us the confidence to recommend the use of APC as an effective and safe procedure in the pulmonary surgery.

[Thermodynamic and kinetic aspects of the hydrolysis of ethyl(R)-2- (benzyloxycarbonylamino)-3-sulfamoylpropionate in the presence of free and immobilized alpha-chymotrypsin]. / Thermodynamische und kinetische Aspekte der Hydrolyse des (R)-2- (Benzyloxycarbonylamino)-3-sulfamoylpropionsäure-ethylesters in Gegenwart von freiem und trägergebundenem alpha-Chymotrypsin.

The hydrolysis of ethyl (R)-2-(benzyloxycarbonylamino)-3-sulfamoylpropionate (blocked cysteic acid S-amide) by native and immobilized alpha-chymotrypsin was studied. The experiments were performed using a constant enzyme/substrate ratio of 1:8 and at a temperature of 10-40 degrees C; the immobilized enzyme was bound to a dialdehyde cellulose matrix. A kinetic equation (Eq.10) was found to be applicable which confirms that the mechanism of the enzyme reaction consists of several stages, irrespective of the enzyme state. The temperature dependence of the reaction velocity was investigated and applied using the Arrhenius equation. The constant value thus obtained for the activating energy showed that the active centres retained their character during immobilization. The differences between the velocities of the reaction with immobilized and with native enzyme corresponded to the different number of active centres during the reaction time. Based on these results a kinetic model of the mechanism of the studied reaction is presented which includes an initial balanced stage of the chemosorption type.