Role of extracorporeal life support in thoracic surgery.

Besides the conventional extracorporeal circulation, commonly used in cardiac surgery, the methods of extracorporeal life support (ECLS) have been applied ever more frequently in thoracic surgery in recent years. The most commonly used modalities of such supports include extracorporeal membrane oxygenation (ECMO) and the Novalung interventional lung assist device (iLA). Successful application of ECLS has led to its more frequent use in general thoracic surgery, especially as a tool to treat hypercapnia and to ensure oxygenation and haemodynamic support. However, these methods are essential in lung transplant programmes; without their help, in most cases, it would not be possible to perform the transplantation or prevent the severe complications associated with critical primary graft dysfunction. Additionally, the extracorporeal circulation also facilitates the performing of specific surgical procedures that would not be feasible under standard conditions or would be associated with an inadequate risk. The application of extracorporeal life supports can fundamentally increase the level of resection when treating advanced intrathoracic malignancies that are in close contact with the heart and large vessels or even directly extend into them. Without the possibility of resecting such structures en bloc, together with the tumour, and, thus, achieving an R0 resection, these malignant tumours are often directly contraindicated for surgery or are operated non-radically, i.e. unsuccessfully. Complete tumour resection is the most important prognostic factor in the surgery.

Malignancy after lung transplantation.

INTRODUCTION: Lung transplantation has become a successful life-saving treatment for patients with end-stage pulmonary disorders. Long-term survival outcomes after lung transplantation have been improving with increasing experience. Malignancies occupy the third position among the causes of death, particularly between years 5 to 10 from lung transplantation. The risk factors include predominantly high doses of immunosuppressive therapy, older age, infections caused by oncogenic viruses and smoking history. METHODS: We retrospectively evaluated all patients undergoing lung transplantation between 2010 and 2019. The aim of this study was to analyze the incidence, type and location of tumors, time from detection, survival time and cause of death in patients with malignant tumors after lung transplantation. RESULTS: In total, 308 lung transplantations were performed at the 3rd Department of Surgery of the 1st Faculty of Medicine, Charles University and University Faculty Hospital in Motol between 2010 and 2019. Posttransplant malignancy was diagnosed in 32 patients; a tumor was detected in the explanted lung in 5 patients. Lung cancer was the most frequent tumor in our study and was found in 13 patients (37%); 6 patients (17%) had a nonmelanoma skin cancer; and posttransplant proliferative disease developed in 4 patients (12.5%). The incidence rate of other types of malignancy was low. Mean of survival after diagnosis was 152 days. CONCLUSION: Life time administration of immunosuppressive therapy in lung transplanted patients plays a key role in the prevention of rejection but on the other hand it represents a risk factor for cancer development. Oncological management of posttransplant cancer is based on reduction of immunosuppressive therapy, combined with surgical resection of solid organ tumors and other types of cancer therapy. Oncology screening tests should be done regularly as a method of prevention, and for an early detection of any tumor.

One-year results from cryopreserved mitral allograft transplantation into the tricuspid position in a sheep experimental model.

Mitral allografts are still used only exceptionally in the mitral or tricuspid position. The main indication remains infectious endocarditis of atrioventricular valves for its flexibility and low risk of infection. The aim of our study was to evaluate 1-year results of mitral allografts transplantation into the tricuspid position in a sheep model. Mitral allografts were processed, cryopreserved, and transplanted into the tricuspid position anatomically (Group I - 11 animals) or antianatomically (Group II - 8 animals). All survivors (4 from Group I, and 3 from Group II) were checked at 3, 6, and 12 months by echocardiography with the exception of one survivor from Group II (which was examinated only visually). Examination throughout follow-up included for mitral allograft regurgitation and annuli dilatation. At postmortem, the papillary muscles were healed and firmly anchored to the right ventricular wall in all subjects. Transventricular fixation of the papillary muscles with buttressed sutures was proven to be a stable, reproducible, and safe method for anchoring mitral allograft leaflets. There were no significant differences between the two implantation methods. Annulus support of mitral allografts might be very useful in this type of operation and could prevent annular dilatation.

Long-term outcomes and prognostic factors of patients with pulmonary carcinoid tumors.

The aim of the study was to evaluate type of surgery, long-term survival and factors influencing outcome of pulmonary carcinoid tumors. We reviewed our database of 137 patients surgically treated for typical or atypical carcinoid tumors at our department between 1998 and 2013. There were 95 (69%) patients with typical carcinoid (87 N0, 6 N1, 2 N2) and 42 (31%) with atypical carcinoid (26 N0, 8 N1, 8 N2). Patients with atypical carcinoid were older than those with typical carcinoid (median age of 57±8.1 and 50.5±15.8 years, respectively, p<0.00001). The resection performed consisted of 6 (4.4%) pneumonectomies, 110 (80.1%) lobectomies and bilobectomies, 15 (11%) sleeve lobectomies, 2 (1.5%) resections of main bronchus and 4 (3%) wedge resections. Overall 5- and 10-year survival rates for different tumors were as follows: typical carcinoid: 97.2% and 89.9%, respectively; atypical carcinoid 71.1% and 62.2%, respectively. Statistical analyses indicated that histology (typical carcinoid, p<0.00001), age (less than 45 years, p=0.004) and nodal status (N0, p=0.0002) were significant prognostic factors for better prognosis. Histological sub-type and nodal involvement appear as the most important factors influencing the prognosis. Systemic lymphadenectomy is recommended and should always be performed.

Mechanical properties of mitral allografts are not reasonably influenced by cryopreservation in sheep model.

A mitral allograft is used exceptionally in the mitral, as well as in the tricuspid position, mostly as an experimental surgical procedure. The authors decided to evaluate the possibility of inserting a cryopreserved mitral allograft into the tricuspid position in a sheep experimental model. Within the framework of this experimental project the mechanical properties of the cryopreserved mitral allograft were tested. A novel methodology studying the functional unit composed of mitral annulus, leaflet, chordae tendinaea, and papillary muscle is presented. A five-parameter Maxwell model was applied to characterize the viscoelastic behavior of sheep mitral valves. A control group of 39 fresh mitral specimens and a test group of 13 cryopreserved mitral allografts from tissue bank were tested. The testing protocol consisted of six loading cycles with 1 mm elongation every 5 min. There was no significant difference in the mean values of the determined parameters (p>0.05) which confirms the main hypothesis that cryopreservation does not influence significantly material parameters characterizing the tissue mechanics. Slight discrepancy is observed in variances of viscous parameters suggesting that the values of the test group may be spread over larger interval due to the treatment.

Lung transplantation in cystic fibrosis patients in the Czech Republic: initial single-center experience.

BACKGROUND: Lung transplantation is a well established treatment for advanced lung diseases. METHODS: We compared the clinical results of patients with cystic fibrosis (CF) entered into the waiting list with those of patients after lung transplantation. RESULTS: Among 36 patients with CF on the waiting list, 23 underwent lung transplantation, 8 died, 3 are still on the waiting list, and 2 were excluded from the waiting list. The median waiting list time of 0.48 years (range, 0.03-2.37) was insignificantly longer for patients who died compared with transplanted patients (0.97 vs 0.44 years). Mortality of waiting-list patients was 25.8%. The median survival of transplant patients of 7.48 years (range 0.00-10.85 years) was significantly lower among patients who were colonized (BCC) versus those who were not Burkholderia cepacia complex (0.19 vs 7.48 years; P = .041). The 1-, 3-, and 5-year patient survivals after lung transplantation were 72.9, 54.4, and 54.4, respectively. CONCLUSION: The results of patients with cystic fibrosis on the waiting list versus after lung transplantation in our center were similar to those reported in the literature. We confirmed a less favorable prognosis of BCC-colonized patients.

Cryopreserved semilunar heart valve allografts: leaflet surface damage in scanning electron microscopy.

OBJECTIVE: Allograft heart valves (AHV), biological valves of human origin, offer potential advantages over conventional xenografts in terms of superior hemodynamics and, perhaps, better durability. The most important factors for long-term AHV clinical performance are the processing and cryopreservation methods. The aim of this study was to evaluate the impact of current processing protocol on valve tissue morphology, mainly to address the effect of successive processing steps on the leaflet surface structure. For the detection of fine changes in endothelial covering and underlying layers, our own modification of the scanning electron microscopy (SEM) technique was utilized. MATERIAL AND METHODS: The study was based on an investigation of 20 AHV (40 specimens). Fourteen valves came from heart-beating donors (multiorgan harvesting) when the heart could not be transplanted for any reason (donor criteria, availability of recipient and/or logistics). Six were obtained at the time of routine postmortems--non heart-beating donors (NHBD). All specimens were initially fixed in Baker's solution. Tissue samples were dissected, dried with hexamethyldisilazane (HMDS), gold-coated, studied and photographed by SEM (Tesla BS 301). In order to define the integrity of the endothelium, subendothelial layers and the quality of the surface under SEM, a special six-level score system was introduced: 1-intact endothelium, 2-confluent endothelium with structural inhomogeneity, 3-disruption of intercellular contacts, 4-separation of endothelial cells, 5-complete loss of endothelium, 6-damage of subendothelial layers). AHV samples were divided into 4 groups for comparison. One aortic AHV "fresh" control sample obtained from a heart-beating donor was evaluated without any processing and was compared with (i) tissue from AHV obtained from NHBD with warm ischemia of 12 and 48 hours, (ii) samples stored at +4 degrees C in saline for 24 h, (iii) antibiotic-treated tissue for 24 h at 37 degrees C and finally with (iv) cryopreserved valves stored in liquid nitrogen (-196 degrees C) for 6-38 months. RESULTS: Our alternative for drying samples by the HMDS method proved to be suitable for thin membranes of human semilunar valves. We were able to detect early changes in the endothelium after harvesting and denudation of the endothelial covering during preservation with and without freezing. The surface of the AHV samples revealed the typical features and score system determined endothelial cell damage. Control "fresh" sample: score 2, (i) NHBD samples with warm ischemia of 12 h: score 3-4, with warm ischemia of 48 h: score 4-5, (ii) samples stored at +4 degrees C in saline for 48 h: score 5-6, (iii) antibiotic-treated tissue for 24 h at 37 degrees C: score 5, (iv) cryopreserved valves stored in liquid nitrogen for 6-38 months: score 5-6. CONCLUSION: SEM (using HMDS drying) together with other methods may be helpful for the morphological control of processing, cryopreservation and liquid nitrogen storage of AHV. Severe AHV leaflet endothelial destruction was proven on AHV grafts. These changes arose already in the initial steps of tissue processing, just after the donor heart harvesting and then at the time of antibiotic valve graft treatment. These results are considered as the starting point for the development of a better preservation protocol.

Side populations of gastrointestinal cancers are not enriched in stem cells.

The side population (SP) phenotype, defined as the reserpine-blockable ability to efflux the nucleic acid dye Hoechst 33342, has been claimed to be enriched for stem cells in several human normal tissues, cancers and cell lines, and thus may be useful for the identification and isolation of cancer stem cells. We demonstrated the presence of SP fractions in all of seven tested gastrointestinal cancer cell lines. Four cell lines were selected (HT29, HGT101, Caco2 and HRA19a1.1) for detailed phenotypic and behavioural analysis with respect to stem cell characteristics. Cell surface marker analysis showed that, contrary to non-SP cells, the SPs entirely lack the expression of CD34. This difference, however, disappeared when the cells were cultured, rendering both populations CD34-positive. Expression of other putative stem cell markers (CD133, CD44, Hes-1, beta-catenin, Musashi-1, Oct-4 and CD117) was identical on SP and non-SPs before and after culturing. Sorted SP and non-SP cells were similarly clonogenic in vitro, tumourigenic in vivo, and displayed similar multipotential differentiation potential in vitro and in vivo. Additionally, culturing cytometrically-sorted SP and non-SP cells showed that the populations are interconvertible, each giving rise to the other. Expression of ABCG2 and Mdr-1, two membrane transporter proteins that have been suggested to be responsible for the drug-effluxing capacities of SP cells, including Hoechst 33342, was identical in non-SP and SP cells, indicating that there may be additional factors responsible for the Hoechst effluxing property in gastrointestinal cancer SP cells. Here, we show that the SP and non-SP fractions, albeit phenotypically distinct populations, do not differ with respect to stem cell-like cell number or behaviour. We thus conclude that the concept of the SP phenotype as a universal marker for stem cells does not apply to gastrointestinal cancer cells. These findings stand in contrast to the observations made in many other tissues and harbour important implications for the future search for intestinal cancer stem cell markers.

The production of rhamnolipid by a Pseudomonas aeruginosa strain isolated from a southern coastal zone in Brazil.

The production and properties of a rhamnolipid-type biosurfactant, synthesized by the Pseudomonas aeruginosa LBM10 strain, isolated from a southern coastal zone in Brazil, were investigated. The assays were conducted in a rotary shaker at 30 degrees C and 180 rpm for a period of 96 h. Soybean oil and sodium nitrate were the best sources of carbon and nitrogen, respectively. A nitrogen-limiting condition (C/N ratio of 100) was favorable to biosurfactant production. The formation of stable emulsions was better in saline concentrations below 0.5%, pH values in the range from 6 to 9 and temperatures in the range from 35 to 40 degrees C, maintaining about 80% of its original activity for salinity up to 3% and 120 min of exposure at 100 degrees C. The biosurfactant may be produced with this microorganism using renewable substrates that are readily available, reaching values of 1.42 g l(-1) measured as rhamnose. This biosurfactant has interesting and useful properties for many industrial applications.

Induction therapy in lung transplantation: initial single-center experience comparing daclizumab and antithymocyte globulin.

UNLABELLED: Acute and chronic rejection remain unresolved problems after lung transplantation, despite heavy multidrug immunosuppression. Because acute rejection is associated with inferior outcomes in lung transplantation, we have routinely employed antithymocyte globulin (ATG) or daclizumab as adjuncts to reduce the incidence of rejection episodes. METHODS: We performed a controlled clinical trial of the two therapies to evaluate differences in postoperative rejection, infection, bronchiolitis obliterans syndrome (BOS) and host survival. Twenty-five consecutive lung transplant patients received ATG (n = 12; group 1) or daclizumab (n = 13; group 2) as an induction agent. The groups showed similar demographics and immunosuppression protocols, differ only in induction agent. RESULTS: No differences were observed in the immediate postoperative outcomes, such as length of hospitalization, ICU stay, or time on ventilator. There were no significant differences in the number of episodes of acute rejection, freedom from BOS, or infections. Freedom from acute rejection was significantly greater with daclizumab than with ATG (P = .037). The 1-year survival for group 1 was 67% and for group 2, 77% (P = .584). CONCLUSIONS: Daclizumab constitutes a safe and effective form of induction immunosuppressive therapy. Using a two-dose administration schedule, daclizumab prolonged the time without acute rejection compared to ATG. The differences in the incidence of infectious complications, acute rejection, or BOS as well as the short-term or long-term results were not significantly different. The results of the study justify the further use of daclizumab as an induction agent in patients following lung transplantation.

Optimization of phycocyanin extraction from Spirulina platensis using factorial design.

Phycocyanin extraction from cyanobacteria Spirulina platensis was optimized using factorial design and response surface techniques. The effects of temperature and biomass-solvent ratio on phycocyanin concentration and extract purity were evaluated to determine the optimum conditions for phycocyanin extraction. The optimum conditions for the extraction of phycocyanin from S. platensis were the highest biomass-solvent ratio, 0.08 gmL(-1), and 25 degrees C. Under these conditions it's possible to obtain an extract of phycocyanin with a concentration of 3.68 mgmL(-1) and purity ratio (A(615)/A(280)) of 0.46.

Initial single-center experience with sirolimus after lung transplantation.

BACKGROUND: Standard immunosuppression after lung transplantation includes calcineurin inhibitors, mycophenolate mofetil, and steroids. Long-term survivors of lung transplantation are often confronted with chronic kidney disease, by definition related to the intake of calcineurin inhibitors. Sirolimus has been increasingly proposed as an alternative immunosuppressive agent due to its absence of nephrotoxicity, which could be used in selected patients. METHODS: We prospectively administered sirolimus as an alternative to calcineurin inhibitors in 10 lung transplantation recipients with persistent drug nephrotoxicity. They were switched from tacrolimus to sirolimus. Four patients also had bronchiolitis obliterans syndrome. The conversion scheme consisted of an immediate stop of tacrolimus and an 6 to 8-mg loading dose of sirolimus, followed by 4 mg/d. After 5 days, the sirolimus dose was adjusted to maintain trough levels between 12 and 18 ng/mL or 6 and 12 ng/mL for combined sirolimus and tacrolimus. Patients were monitored for renal and graft function as well as clinical status. RESULTS: A significant decrease in creatinine was observed after 1 week of treatment (P = .011). Azotemia decreased after 1 month, remaining stable (P < .01). Pulmonary function tests did not show significant modification from before sirolimus, inception in patients with or without bronchiolitis obliterans syndrome. There were seven infections. One patient died of complications related to bronchiolitis obliterans. CONCLUSION: Sirolimus was a useful alternative immunosuppressant, allowing significant tacrolimus withdrawal in transplant recipients with renal impairment. Sirolimus administration allowed recovery of renal function with low morbidity; it was useful for rescue of chronic renal impairment after lung transplantation.

Allograft semilunar cardiac valves processing and cryopreservation - morphology in scanning electron microscope.

OBJECTIVE: The most important factors of long term clinical performance of biological heart valve prostheses are methods of processing and cryopreservation. That is why we decided to evaluate the impact of current Allograft Heart Valves (AHV) Bank protocol on valve tissue morphology. Scanning electron microscope (SEM) is a valuable tool for investigation of biological surfaces. In case of cardiac valves it is especially suitable for detection of fine changes in endothelial covering and underlying layers. MATERIAL AND METHODS: "Fresh" aortic and pulmonary AHV samples, harvested from "heart-beating" cadaveric donors, were compared with (1) tissue from AHV obtained from non heart-beating donors, (2) samples stored in 4 degrees C saline for 24 h, (3) antibiotic treated tissue for 24 h at 37 degrees C and finally (4) cryopreserved valves, stored in liquid nitrogen (-196 degrees C) for 6-38 months. All samples were dissected, dried with hexamethyldisilazane (HMDS), gold coated, studied and photographed by SEM (Tesla BS 301). RESULTS: Our alternative method of drying samples by the HMDS method proved to be suitable for thin membranes of human semilunar valves. We were able to detect early changes in the endothelium after harvesting, and denudation of the endothelial covering during preservation with and without freezing. CONCLUSION: SEM (using HMDS drying) along with other methods may be helpful for the morphological control of processing, cryopreservation and liquid nitrogen storage of AHV. According to the current findings we have to avoid washing of AHV in saline after harvesting.

[Resection of metastatic nondifferentiated carcinoma of sternum with thoracic wall reconstruction and simultaneous myocardial revascularization for ischemic heart disease--case report]. / Resekce sterna s rekonstrukcí hrudní steny pro metastázu nediferencovaného karcinomu v kombinaci s revaskularizací myokardu pro ischemickou chorobu srdecní--kazuistika.

Authors offer the case report of a patient with metastatic non differentiated carcinoma of sternum simultaneously suffering from ischemic heart disease. The patient underwent actinotherapy & hyperthermia followed by resection of sternum and coronary artery bypass grafting in one session. Chest wall defect was closed by means of latissimus dorsi muscle rotation. Postoperative palliative chemotherapy started 16 weeks postoperatively. Primary tumor was not found, neither preoperatively nor during the 36 months' postoperative remission.

Stem cells and cancer: an intimate relationship.

Tumour-wide 'omics' approaches have long held sway as the approach to identifying useful therapeutic targets. This view is changing with the realization that many, if not all, cancers contain a minority population of self-renewing stem cells, the cancer stem cells, which are entirely responsible for sustaining the tumour as well as giving rise to proliferating but progressively differentiating cells that are responsible for much of the cellular heterogeneity that is so familiar to histopathologists. Moreover, although many tumours probably have their origins in normal stem cells, persuasive evidence from the haematopoietic system suggests that genetic alterations in more committed progenitor cells can reactivate the self-renewal machinery, resulting in a further source of cancer stem cells. Thus, the bulk of the tumour is not the problem, and so the identification of cancer stem cells and the factors that regulate their behaviour are likely to have an enormous bearing on the way that we treat neoplastic disease in the future.

[Simultaneous cardiac and thoracic operations]. / Simultane Herz- und Lungenoperationen.

BACKGROUND: Optimal surgical strategy in patients with combined disease of heart (mainly ischemic heart disease or critical valve disease) and other thoracic organs (mainly pulmonary carcinoma) is still controversial. METHODS: From 1997 to 2004, 13 simultaneous cardiac and thoracic operations were performed in 13 patients. Most of them were necessary for combinations of symptomatic coronary artery disease (CAD) and bronchogenic carcinoma (BCA). PATIENT CHARACTERISTICS: 11 patients showed CAD, mean preoperative LVEF was 44 %. SURGICAL PROCEDURE: Surgical exposure was performed via sternotomy in 10 patients, the rest of the patients underwent thoracotomy. Seven patients were operated on cardiopulmonary bypass, the others underwent an off-pump procedure. Eleven patients underwent CABG, mean number of anastomoses were 2.1 (range 1-4), two patients underwent aortic valve replacement. One patient underwent radical removal of pulmonary adenocarcinoma with local expansion into the left atrium. For the lung cancer lobectomy was necessary in 8, pneumectomy in 1, extirpation of multiple metastases in 1, resection of the trachea in 1 patient. Histological diagnosis was epidermoid carcinoma in 6, adenocarcinoma in 3, undifferentiated carcinoma in 1, metastasis of Grawitz tumor in 1, pneumoconiosis in 1 patient. RESULTS: No patient died in hospital. One patient had to be re-explored for bleeding. Mean blood loss, duration of intubation and length of hospital stay were not different from other patients who underwent cardiac operation only. CONCLUSION: In accordance with the majority of the data published in the literature, combined procedures did not negatively influence hospital morbidity and mortality. Simultaneous operations eliminate the necessity of a second operation and do not delay the postoperative oncological therapy. Long-term results are primarily determined by histological diagnosis and by the extent of the tumor.

Accuracy of angiography and Doppler ultrasonography in the detection of carotid stenosis: a histopathological study of 123 cases.

BACKGROUND: A prospective study was performed comparing the accuracy of digital subtraction angiography (DSA) and Doppler ultrasonography (DUS) stenosis findings with measurements on histological specimens. METHOD: DSA and DUS were used to evaluate carotid stenosis and were compared with measurements on histological specimens. Intact carotid plaques from 123 cases were removed in one piece during surgery. The specimens were histologically processed and examined in transverse sections. The smallest inner and correlating outer diameters were measured and the extent of stenosis was calculated. Carotid artery stenoses were compared and statistics done. Specimens in symptomatic cases were divided into 3 groups: stenosis 30-49% (Group 1), stenosis 50-69% (Group 2) and stenosis 70-99% (Group 3). Specimens in asymptomatic cases were divided into two groups: stenosisor=60% (Group B). FINDINGS: Wilcoxon paired tests revealed significant differences between DSA, DUS and measurements on histological specimens. In severe stenoses only, no significant difference was observed between stenosis measurement according to the European Carotid Surgery Trial (ECST) angiography methodology and measurements on histological specimens. The most pronounced differences were found between angiography methodology of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and measurements on histological specimens. When investigating how often preoperative measurement classified stenosis into the same Group of stenoses as postoperative measurement, DUS was the most accurate diagnostic tool. CONCLUSIONS: This study confirmed our previous results, i.e., angiography underestimates the degree of carotid artery stenosis. DUS seems to be more accurate in classifying stenoses into different groups to the extent of narrowing of the carotid arteries. These results make the position of angiography in diagnostic algorithm of carotid stenoses investigations even more questionable.

Implantation of cryopreserved mitral allograft into the tricuspid position in an experimental study in sheep: technical aspects of implantation and immediate results evaluated by epicardial echocardiography.

AIMS: Cryopreserved mitral allograft valve (MAV) offers theoretical advantages over conventional mechanical or biological prostheses in tricuspid position, especially in infectious endocarditis patients. MAV processing and tricuspid valve (TV) replacement in a sheep model is described. METHODS AND RESULTS: In 20 adult sheep, MAV were harvested, processed and cryopreserved. One month later, recipient's TV were excised and the MAVs were transplanted into the tricuspid position in 13 sheep, under general anaesthesia, via a right thoracotomy, with an extracorporeal circulation (ECC) and cardioplegic heart arrest. Both MAV papillary muscles were anchored into the right ventricular wall by transmural stitches and the MAV anulus was sewn into the recipient's tricuspid anulus. After weaning from ECC, the anatomy and function of the MAV in the tricuspid position was assessed by epicardial echocardiography. The average duration of the ECC was 58 minutes (42-88), the cardioplegic heart arrest was 36 minutes (28-45). Weaning from EEC was always uneventful. Right atrial & pulmonary artery pressure measurements and epicardial echocardiography documented good function of all MAVs. CONCLUSION: MAV remained mechanically strong enough for implantation into the tricuspid position. Reproducible technique of MAV transplantation into the tricuspid position with excellent early postoperative haemodynamic performance was developed.

[Ischemic mitral regurgitation. Clinical review emphasizing the surgical treatment]. / Ischemická mitrální regurgitace Klinické review s durazem na chirurgickou lécbu.

Ischemic mitral regurgitation represents comparatively frequent complication of the myocardial infarction. Presence of the ischemic mitral regurgitation has a negative effect on the immediate mortality after the myocardial infarction and on the long-term survival. Ischemic mitral regurgitation is a functional, not structural impairment of the mitral valve and it is caused by altered geometry of the left ventricle. The article deals with the development and pathophysiology namely of the chronic ischemic mitral regurgitation and with the contemporary potential of surgical treatment of that serious complication of the ischemic heart disease.

Optimization of extracellular lipase production by Geotrichum sp. using factorial design.

Response surface methodology was employed to study the effects of carbon source (soy oil, olive oil and glucose) and nitrogen source concentrations (corn steep liquor and NH(4)NO(3)) on the lipase production by Geotrichum sp. The experiment included a 2(4) central composite rotatable design (CCRD) and four others 2(3) CCRD. According to the responses from the experimental designs, the effects of each variable were calculated and the interactions between them were determined. The response surface methodology was applied for the optimization of the nutrient concentrations in the culture medium for the enzyme production, at 30 degrees C. The optimum medium composition for lipase production by Geotrichum sp. was ammonium nitrate 2.1-2.5%, corn steep liquor 13-15% and soy oil 0.6% as carbon source, which lead to a lipase activity of about 20 U/ml. Using olive oil as carbon source, the optimum composition was ammonium nitrate 0.8-1%, corn steep liquor 13-15% and olive oil 0.6%, leading to an activity of 17 U/ml.