Applications of Monte Carlo Simulation in Modelling of Biochemical Processes

The biochemical models describing complex and dynamic metabolic systems are typically multi-parametric and non-linear, thus the identification of their parameters requires nonlinear regression analysis of the experimental data. The stochastic nature of the experimental samples poses the necessity to estimate not only the values fitting best to the model, but also the distribution of the parameters, and to test statistical hypotheses about the values of these parameters. In such situations the application of analytical models for parameter distributions is totally inappropriate because their assumptions are not applicable for intrinsically non-linear regressions. That is why, Monte Carlo simulations are a powerful tool to model biochemical processes

Surgical treatment of patients with chronic constipation - experience of Clinic of Coloproctology - Varna

BACKGROUND: Patients with chronic constipation can be difficult to manage either medically or surgically. We used Roma classification as criteria for including patients in our study. There are many diseases which could lead to chronic constipation. If they are treated by a surgeon, there can be obtained a permanent therapeutic effect. The group of patients with idiopathic chronic constipation couldn't obtain satisfying effect by surgical treatment, which was presided by inaccurate and embarrassed selection. Our aim is to present the results of experience of Clinic of General and Operative Surgery, Varna, Bulgaria.MATERIAL: For a period of 10 years, we have been operated 52 patients with diagnosis as morbus Pair (15 patients), megacolon (31 patients), and idiopathic chronic constipation (6 patients). The main indication for undergoing surgical treatment was the retention of more then 20% of the applied barium enema after the 5th day from irrigography. There were applied the followed operative methods: colectomy, subtotal colectomy, hemicolectomy, resection of the colon sygmoideum, anterior resection of the rectum and mobilization of the lineal flexure. We did analysis of the results. The evaluation of curativeness to applied methods was done. We followed the quality of life of our patients from 11 months to 6.2 years (median 3.2 years).CONCLUSION: The presence of organic disease is associated with very good therapeutic effect from the surgical treatment of chronic constipation. The problem with idiopathic chronic constipation remains unsolved when colectomy with ileo-recto anastomosis was undergone. The right selection of patients is a crucial factor for the success of the surgical treatment

Myosin as cofactor and substrate in fibrinolysis

AbstractMyosin accelerates plasminogen activation by tissue-type plasminogen activator (tPA), and is degraded extensively by plasmin. Myosin binds both tPA and plasminogen, and enhances activation of des1-77-plasminogen by tPA but not by urokinase-type plasminogen activator (uPA). Myosin decreases KM and increases kcat for des1-77-plasminogen activation by tPA, to yield catalytic efficiencies in excess of 8000 M−1 s−1. The effect of myosin is attributed to its C-terminal portion, the myosin rod. With a KM of 3 μM, myosin is a high-affinity substrate for plasmin. The findings indicate that myosin is a cofactor for plasminogen activation and a substrate for plasmin

CALCULATION OF LOSSES OF ACTIVE POWER AND ENERGY IN TRANSMISSION LINES AND TRANSFORMERS, AS A PART OF THE ELECTRICAL DISTRIBUTION POWER NETWORK

The paper inhere discusses the impact of renewable distributed generation sources upon the power and energy losses in electrical distribution power networks where these sources are attached. In addition a set of mathematical expressions to calculate these active power and energy losses are presented with the respective examples and implementation

Peritoneal metastases in colorectal cancer

Peritoneal carcinomatosis (PC) is a common evolution of cancer of the gastrointestinal tract, and has been traditionally regarded as a terminal disease with short median survival. During the last 20 years, due to its favourable oncologic results, a new loco-regional therapeutic approach, combining cytoreductive surgery with intra-operative intraperitoneal chemotherapy has achieved an important development. After liver metastatic disease, peritoneal carcinomatosis is the second most frequent cause of death in colorectal cancer patient is defined as a stage IV tumour which prognosis is the worst. The extent of peritoneal carcinomatosis is, however, difficult for assessment preoperatively, and precise evaluation is most often performed during surgical exploration. Cytoreductive surgery associated with chemotherapy for the treatment of peritoneal carcinomatosis should be performed in young patients with limited and resectable carcinomatosis, in specialized institutions involved in the management of peritoneal surface malignancies

Local excision for early rectal cancer - is it proper surgical decision?

Sphincter preservation, disease control, and long-term survival are the main goals in the treatment of rectal cancer. Although transanal local excision is attractive because it is a sphincter spar ing procedure, some contradictory data exist in the literature about its ability to locally control disease and provide over all survival comparable with radical procedures, even for patients with early stage tumor. In patients with early rectal cancer (T1), local excision may be an alternative approach in highly selected patients. For more advanced rectal cancer, radical surgical resection is the treatment of choice.METHODS: We reviewed the literature to identify the current recurrence and survival rates of both techniques as well as the salvage surgery success, only 1 study was prospective, 5 were comparative, and 5 were case reports. We present a case report of a woman with local excision of rectal tumor. Five years later a rectal recurrence has showed up. We describe the case and make some conclusions.Scripta Scientifica Medica 2009; 41(2): 169-171

Endoscopic Submucosal Dissection for Early Colon Cancer

Endoscopic submucosal dissection (ESD) was first implemented in early gastric cancer allowing for en-bloc resection of the lesions. With the experience came the expertise to introduce ESD for early colon cancer (ECC). ESD demonstrates several advantages in comparison with the endoscopic mucosa resection. It allows accurate histological assessment of the depth of invasion, minimizes the risk of local recurrence and helps in the determination of additional therapy. Indications for ESD are placed only after adequate endoscopic morphological classification of the lesions excluding higher risk of nodal metastases. This chapter provides an overview of the application of ESD techniques in ESD for ECC and provides assessment on its technical aspects and complications. In order to decrease the rate of complications a standard protocol for the ESD should be adopted. The protocol includes recommendations for patient selection, bowel and patient preparation, appropriate equipment (knives, endoscopes, and power devices). The chapter will review the current ESD techniques and oncological results. ESD could have great impact on the treatment of early colon cancer. Its role is already proven in rectal localizations and despite the challenges it should be adopted for the colon. Safe strategy for ESD is the cornerstone in decreasing complications, which includes suitable resection of specialized ESD devices