An accurate prediction of high-frequency circuit behaviour, Journal of Telecommunications and Information Technology, 2005, nr 1

An accurate way to predict the behaviour of an RF analogue circuit is presented. A lot of effort is required to eliminate the inaccuracies that may generate the deviation between simulation and measurement. Efficient use of computer-aided design and incorporation of as many physical effects as possible overcomes this problem. Improvement of transistor modelling is essential, but there are many other un-solved problems affecting the accuracy of RF analogue circuit modelling. In this paper, the way of selection of accurate transistor model and the extraction of parasitic elements from the physical layout, as well as implementation to the circuit simulation will be presented using two CMOS circuit examples: an amplifier and a voltage controlled oscillator (VCO). New simulation technique, electro-magnetic (EM)-co-simulation is introduced

Usefulness of Pure Laparoscopic Hepatectomy for Hepatocellular Carcinoma in a Severely Cirrhotic Patient

The number of patients undergoing laparoscopic hepatectomy has rapidly increased in recent years, and indications for this procedure are gradually expanding. Pure laparoscopic hepatectomy is reportedly useful in cases with severe liver cirrhosis. A 55-year-old woman under observation for liver cirrhosis was found to have hepatocellular carcinoma in liver segment III and was referred to our hospital for surgery. The tumor was located in the edge of liver segment III, where percutaneous ablation therapy was unsuitable. Since her hepatic functional reserve was poor, pure laparoscopic partial hepatectomy was performed. The postoperative course was favorable, with no ascites retention, edema or weight gain. The greatest advantage of pure laparoscopic hepatectomy for hepatocellular carcinoma with concomitant liver cirrhosis is that postoperative ascites retention is minimal, meaning that there is little risk of water-electrolyte imbalance associated with ascites retention or hypoproteinemia. This is believed to be because the abdominal incision is small and mobilization of the liver is minimized, reducing the destruction of the routes of collateral lymph flow and blood flow generated in patients with liver cirrhosis. Pure laparoscopic hepatectomy may be a treatment choice for patients with hepatocellular carcinoma and concomitant severe liver cirrhosis

The Application of a Three-Step Proteome Analysis for Identification of New Biomarkers of Pancreatic Cancer

We searched for novel tumor markers of pancreatic cancer by three-step serum proteome analysis. Twelve serum abundant proteins were depleted using immunoaffinity columns followed by fractionation by reverse-phase high-performance liquid chromatography. Proteins in each fraction were separated by two-dimensional gel electrophoresis. Then the gel was stained by Coomassie Brilliant Blue. Protein spots in which the expression levels were significantly different between cancer and normal control were identified by LC-MS/MS. One hundred and two spots were upregulated, and 84 spots were downregulated in serum samples obtained from patients with pancreatic cancers, and 58 proteins were identified by mass spectrometry. These candidate proteins were validated using western blot analysis and enzyme-linked immunosorbent assay (ELISA). As a result of these validation process, we could confirm that the serum levels of apolipoprotein A-IV, vitamin D-binding protein, plasma retinol-binding protein 4, and tetranectin were significantly decreased in patients with pancreatic cancer

Hepatocyte apoptosis is enhanced after ischemia/reperfusion in the steatotic liver

Liver steatosis is associated with organ dysfunction after hepatic resection and transplantation which may be caused by hepatic ischemia/reperfusion injury. The aim of the current study was to determine the precise mechanism leading to hepatocyte apoptosis after steatotic liver ischemia/reperfusion. Using a murine model of partial hepatic ischemia for 90 min, we examined the levels and pathway of apoptosis, and the peroxynitrite expression, serum alanine aminotransferase levels, and liver histology 1 and 4 h after reperfusion. In the steatotic liver, the peroxynitrite expression increased after ischemia/reperfusion. Significant hepatocyte apoptosis in the steatotic liver was seen after reperfusion, caused by upregulation of cleaved caspases 9 and 3, but not caspase 8. Serum alanine aminotransferase levels were elevated and histological examination revealed severe liver injury in the steatotic liver 4 h after reperfusion. In mice treated with aminoguanidine, ischemia/reperfusion-induced increases in serum alanine aminotransferase levels and apoptosis were significantly reduced in steatotic liver compared with mice treated with phosphate buffered saline. Survival of mice with steatotic livers significantly improved by treatment with aminoguanidine. Our data suggested that the steatotic liver is vulnerable to hepatic ischemia/reperfusion, leading to significant hepatocyte apoptosis by the mitochondrial permeability transition, and thereby resulting in organ dysfunction

Purpose, use, and preparation of clinical practice guidelines for the management of biliary tract and ampullary carcinomas

Apart from periampullary carcinoma, the prognosis of biliary tract carcinomas, including hilar cholangiocarcinoma, extrahepatic biliary tract carcinoma, and gallbladder carcinoma, remains poor. Sophisticated diagnostic skills and treatment methods and their application are naturally required to achieve better treatment results for biliary tract carcinomas. However, it is not too much to say that, due to the paucity of high-level evidence for the management of these carcinomas, medical care by healthcare providers in clinics and at medical institutes throughout the world is currently delivered without common consensus and common standards. The clinical practice guidelines for the management of biliary carcinoma outlined here were produced with the aim that they could be used by physicians involved in the care of biliary tract carcinomas, as indicators that could help them provide their patients with the most appropriate care possible at this time. Also, the guidelines were prepared to provide measures that could assure patients with biliary tract carcinomas of safe medical care. The present guidelines are characterized by their clarification of clinical questions assumed to be often shared by healthcare professionals. For clarity, we divided the contents of the guidelines into eight areas. In each area, clinical questions are presented, together with recommendations of clinical actions in response to the question. As mentioned already, there is a paucity of high-level evidence in this area; therefore, the recommendations are classified into grades, of which there are five: A, strongly recommend performing the clinical action; B, recommend performing the clinical action; C1, the clinical action may be useful, although there is a lack of high-level scientific evidence; C2, clinical action not definitively recommended ecause of insufficient scientific evidence; D, recommend not performing the clinical action. The grading of the recommendations is based on the determination of the level of evidence in references on which the recommendation is based

Stenting and interventional radiology for obstructive jaundice in patients with unresectable biliary tract carcinomas

Together with biliary drainage, which is an appropriate procedure for unresectable biliary cancer, biliary stent placement is used to improve symptoms associated with jaundice. Owing to investigations comparing percutaneous transhepatic biliary drainage (PTBD), surgical drainage, and endoscopic drainage, many types of stents are now available that can be placed endoscopically. The stents used are classified roughly as plastic stents and metal stents. Compared with plastic stents, metal stents are of large diameter, and have long-term patency (although they are expensive). For this reason, the use of metal stents is preferred for patients who are expected to survive for more than 6 months, whereas for patients who are likely to survive for less than 6 months, the use of plastic stents is not considered to be improper. Obstruction in a metal stent is caused by a tumor that grows within the stent through the mesh interstices. To overcome such problems, a covered metal stent was developed, and these stents are now used in patients with malignant distal biliary obstruction. However, this type of stent has been reported to have several shortcomings, such as being associated with the development of acute cholecystitis and stent migration. In spite of these shortcomings, evidence is expected to demonstrate its superiority over other types of stent

Radiation therapy and photodynamic therapy for biliary tract and ampullary carcinomas

The purpose of radiation therapy for unresectable biliary tract cancer is to prolong survival or prolong stent patency, and to provide palliation of pain. For unresectable bile duct cancer, there are a number of studies showing that radiation therapy is superior to the best supportive care. Although radiation therapy is used in many institutions, no large randomized controlled trials (RCTs) have been performed to date and the evidence level supporting the superiority of this treatment is low. Because long-term relief of jaundice is difficult without using biliary stenting, a combination of radiation therapy and stent placement is commonly used. As radiation therapy, external-beam radiation therapy is usually performed, but combined use of intraluminal brachytherapy with external beam radiation therapy is more useful for making the treatment more effective. There are many reports demonstrating improved response rates as well as extended survival and time to recurrence achieved by this combination therapy. Despite the low level of the evidence, this combination therapy is performed at many institutions. It is expected that multiinstitutional RCTs will be carried out. Unresectable gallbladder cancer with a large focus is usually extensive, and normal organs with high radio sensitivity exist contiguously with it. Therefore, only limited anticancer effects are to be expected from external beam radiation therapy for this type of cancer. The number of reports on ampullary cancer is small and the role of radiation therapy in this cancer has not been established. Combination treatment for ampullary cancer consists of either a single use of intraoperative radiation therapy, postoperative external beam radiation therapy or intraluminal brachytherapy, or a combination of two or three of these therapies. Intraoperative radiation therapy is superior in that it enables precise irradiation to the target site, thereby protecting adjacent highly radiosensitive normal tissues from irradiation. There are reports showing extended survival, although not significant, in groups undergoing intraoperative or postoperative radiation therapy compared with groups without radiation therapy. To date, there are no reports of large RCTs focusing on the significance of radiation therapy as a postoperative adjuvant treatment, so its usefulness as a postoperative adjuvant treatment is not proven. An alternative treatment is photodynamic therapy. There is an RCT demonstrating that, in unresectable bile duct cancer, extended survival and improved quality of life (QOL) have been achieved through a combination of photodynamic therapy and biliary stenting, compared with biliary stenting alone. Results from large RCTs are desired

Preoperative biliary drainage for biliary tract and ampullary carcinomas

We posed six clinical questions (CQ) on preoperative biliary drainage and organized all pertinent evidence regarding these questions. CQ 1. Is preoperative biliary drainage necessary for patients with jaundice? The indications for preoperative drainage for jaundiced patients are changing greatly. Many reports state that, excluding conditions such as cholangitis and liver dysfunction, biliary drainage is not necessary before pancreatoduodenectomy or less invasive surgery. However, the morbidity and mortality of extended hepatectomy for biliary cancer is still high, and the most common cause of death is hepatic failure; therefore, preoperative biliary drainage is desirable in patients who are to undergo extended hepatectomy. CQ 2. What procedures are appropriate for preoperative biliary drainage? There are three methods of biliary drainage: percutaneous transhepatic biliary drainage (PTBD), endoscopic nasobiliary drainage (ENBD) or endoscopic retrograde biliary drainage (ERBD), and surgical drainage. ERBD is an internal drainage method, and PTBD and ENBD are external methods. However, there are no reports of comparisons of preoperative biliary drainage methods using randomized controlled trials (RCTs). Thus, at this point, a method should be used that can be safely performed with the equipment and techniques available at each facility. CQ 3. Which is better, unilateral or bilateral biliary drainage, in malignant hilar obstruction? Unilateral biliary drainage of the future remnant hepatic lobe is usually enough even when intrahepatic bile ducts are separated into multiple units due to hilar malignancy. Bilateral biliary drainage should be considered in the following cases: those in which the operative procedure is difficult to determine before biliary drainage; those in which cholangitis has developed after unilateral drainage; and those in which the decrease in serum bilirubin after unilateral drainage is very slow. CQ 4. What is the best treatment for postdrainage fever? The most likely cause of high fever in patients with biliary drainage is cholangitis due to problems with the existing drainage catheter or segmental cholangitis if an undrained segment is left. In the latter case, urgent drainage is required. CQ 5. Is bile culture necessary in patients with biliary drainage who are to undergo surgery? Monitoring of bile cultures is necessary for patients with biliary drainage to determine the appropriate use of antibiotics during the perioperative period. CQ 6. Is bile replacement useful for patients with external biliary drainage? Maintenance of the enterohepatic bile circulation is vitally important. Thus, preoperative bile replacement in patients with external biliary drainage is very likely to be effective when highly invasive surgery (e.g., extended hepatectomy for hilar cholangiocarcinoma) is planned

Guidelines for chemotherapy of biliary tract and ampullary carcinomas

Few randomized controlled trials (RCTs) with large numbers of patients have been conducted to date in patients with biliary tract cancer, and standard chemotherapy has not been established yet. In this article we review previous studies and clinical trials regarding chemotherapy for unresectable biliary tract cancer, and we present guidelines for the appropriate use of chemotherapy in patients with biliary tract cancer. According to an RCT comparing chemotherapy and best supportive care for these patients, survival was significantly longer and quality of life was significantly better in the chemotherapy group than in the control group. Thus, chemotherapy for patients with biliary tract cancer seems to be a significant treatment of choice. However, chemotherapy for patients with biliary tract cancer should be indicated for those with unresectable, locally advanced disease or distant metastasis, or for those with recurrence after resection. That is why making the diagnosis of unresectable disease should be done with greatest care. As a rule, pathological diagnosis, including cytology or histopathological diagnosis, is preferable. Chemotherapy is recommended in patients with a good general condition, because in patients with general deterioration, such as those with a performance status of 2 or 3 or those with insufficient biliary decompression, the benefit of chemotherapy is limited. As chemotherapy for unresectable biliary tract cancer, the use of gemcitabine or tegafur/gimeracil/oteracil potassium is recommended. As postoperative adjuvant chemotherapy, no effective adjuvant therapy has been established at the present time. It is recommended that further clinical trials, especially large multi-institutional RCTs (phase III studies) using novel agents such as gemcitabine should be performed as soon as possible in order to establish a standard treatment