Experimental and stochastic analysis of lyophilisation.

The development of the freeze-drying processes through the use of a combination of targeted experiments and the application of multidimensional computational models is applied increasingly in pharmaceutical practice, especially for scale-up purposes. This study deals with the analysis of uncertainties in the data on material properties and model parameters, and their influence on the results delivered by advanced computational models of lyophilisation. As a means of uncertainty analysis, the Stochastic Collocation Method is applied, allowing the use of existing reliable deterministic models as black boxes in the stochastic computations. As a deterministic model, the lyophilisation model is used, based on the axisymmetric approximation of a vial, and the Boundary Element Method as a solver. Five parameters, covering material properties, process conditions and model constants, are selected for the sensitivity analysis simulation of the lyophilisation of an aqueous mannitol solution. The results show that during the initial stage of the primary drying heat transfer from the shelf is crucial, and that the uncertainties in the contact surface area and material properties of the vial play a more important role than the thermal properties of the drying material. When the temperature of the material reaches its distinct primary drying stage level the mass transfer through the porous cake becomes the most important, with great sensitivity to the Knudsen diffusivity in the porous cake. We observed uncertainties in the results for the primary drying time in the order of ±6%, and uncertainties in the results for temperatures of ±0.6°C in the frozen material and ±3°C in the porous cake. The uncertainty analysis proved to be a great help in determining the critical parameters in the heat and mass transfer during the important primary drying step, which led to a better definition of the numerical model for use in the context of design space determination.

Emphysematous gastritis -- case report and review of the literature.

Emphysematous gastritis is a rare form of phlegmonous gastritis caused by invasion of the stomach wall by gas-forming bacteria. This clinical entity was first described by Fraenkel in 1889. The authors report the case of a 58-year-old patient with end-stage renal failure under treatment with hemodialysis for the past year. He was admitted on account of pain in the lower abdomen. During the diagnostic procedure, emphysematous gastritis and acute cholecystitis were confirmed. An acute abdomen developed and an emergency laparotomy was performed. During the procedure, the necrotic gallbladder was removed. The patient died on the following day due to multiorgan failure and septic shock. According to the literature, emphysematous gastritis is generally a fatal disease. Air in the wall of the stomach is a rare finding with a broad differential diagnosis.

Epicardial electrode insertion by means of video-assisted thoracic surgery technique.

BACKGROUND: The number of patients who depend on pacemaker (PM) insertion is steadily increasing. Slovenia has two centers for PM insertion, in which 250 such procedures are performed every year. Thus, with regard to the number of procedures per year per million inhabitants, Slovenia holds a middle position in the list of countries. METHOD: We report a patient with cardiomyopathy, complete A-V block (A-V block III) and permanent transvenous pacing lead replacements. The resulting thrombosis of the superior vena cava compelled us to insert an epicardial permanent pacing lead. Video-assisted thoracic surgery (VATS) technique was selected. RESULTS: Surgery was safe for the patient, of 40 minutes' duration, and with minimum blood loss. The postoperative course was devoid of complications, the patient's circulation was stable, and he was able to leave the hospital one week later. CONCLUSIONS: We believe that the choice of the thoracoscopic method of epicardial permanent pacing lead insertion is appropriate, and that the method is safe and promising as it broadens the indications for the VATS technique.