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EN
This paper shows advantages of using price range in volatility modeling and forecasting. It is known that price range, defined as a difference between the logarithms of the highest and the lowest price of an asset, is a useful volatility approximation. In this paper three different range-based models are compared with commonly used residual-based GARCH model in terms of goodness of fit and forecasting accuracy. Each model is estimated on daily data covering six currency pairs quoted to PLN. Despite being equally simple as residual-based GARCH model, range-based models generally perform better. Forecasts generated by range-based models are more precise, moreover they seems to better capture volatility clustering phenomenon.
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Content available remote Management of Patients With Upper Gastrointestinal Bleeding
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EN
Surgical removal of the gallbladder is indicated in nearly all cases of complicated acute cholecystitis. In the 1990s, laparoscopic cholecystectomy became the method of choice in the treatment of cholecystolithiasis. Due to a large inflammatory reaction in the course of acute inflammation, a laparoscopic procedure is conducted in technically difficult conditions and entails the risk of complications. The aim of this paper was: 1) to analyze ultrasound images in acute cholecystitis; 2) to specify the most common causes of conversion from the laparoscopic method to open laparotomy; 3) to determine the degree to which the necessity for such a conversion may be predicted with the help of ultrasound examinations. Material and methods: In 1993–2011, in the Second Department and Clinic of General, Gastroenterological and Oncological Surgery of the Medical University in Lublin, 5,596 cholecystectomies were performed including 4,105 laparoscopic procedures that constituted 73.4% of all cholecystectomies. Five hundred and forty-two patients (13.2%) were qualified for laparoscopic procedure despite manifesting typical symptoms of acute cholecystitis in ultrasound examination, which comprise: thickening of the gallbladder wall of > 3 mm, inflammatory infiltration in the Calot’s triangle region, gallbladder filled with stagnated or purulent contents and mural or intramural effusion. Results: In the group of operated patients, the conversion was necessary in 130 patients, i.e. in 24% of cases in comparison with 3.8% of patients with uncomplicated cholecystolithiasis (without the signs of inflammation). The conversion most frequently occurred when the assessment of the anatomical structures of the Calot’s triangle was rendered more difficult due to local inflammatory process, mural effusion and thickening of the gallbladder wall of >5 mm. The remaining changes occurred more rarely. Conclusions: Based on imaging scans, the most common causes of conversion included inflammatory infiltration in the Calot’s triangle region, mural effusion and wall thickening to > 5 mm. The classical cholecystectomy in acute cholecystitis should be performed in patients with three major local complications detected on ultrasound examination and in those, who manifest acute clinical symptoms.
PL
Operacyjne usunięcie pęcherzyka żółciowego jest wskazane praktycznie we wszystkich przypadkach powikłanego, ostrego zapalenia pęcherzyka żółciowego. W latach dziewięćdziesiątych metodą z wyboru w leczeniu objawowej kamicy pęcherzyka żółciowego stała się cholecystektomia laparoskopowa. Z uwagi na duży odczyn zapalny w przebiegu ostrego stanu zapalnego zabieg laparoskopowy jest przeprowadzany w trudnych technicznie warunkach i wiąże się z ryzykiem wystąpienia powikłań. Celem pracy były: 1) analiza obrazów ultrasonograficznych przypadków ostrego zapalenia pęcherzyka żółciowego; 2) ustalenie najczęstszych przyczyn konwersji z metody laparoskopowej do otwartej laparotomii; 3) określenie, w jakim stopniu za pomocą badania ultrasonograficznego można przewidzieć potrzebę konwersji. Materiał i metoda: W latach 1993–2011 w II Klinice i Katedrze Chirurgii Ogólnej, Gastroenterologicznej i Nowotworów Układu Pokarmowego UM w Lublinie wykonano 5596 cholecystektomii, w tym 4105 zabiegów laparoskopowych, co stanowiło 73,4% wszystkich przeprowadzonych cholecystektomii. Pomimo typowych objawów ostrego zapalenia pęcherzyka w badaniu ultrasonograficznym, do których zaliczamy pogrubienie ściany pęcherzyka > 3 mm, naciek zapalny okolicy trójkąta Calota, wypełnienie pęcherzyka treścią zastoinową lub ropną, wysięk śródścienny lub przyścienny, 542 chorych (13,2%) zakwalifikowano do leczenia metodą laparoskopową. Wyniki: W grupie pacjentów operowanych konwersja była konieczna u 130 osób – w 24% przypadków w porównaniu z 3,8% chorych z niepowikłaną kamicą pęcherzyka żółciowego (bez cech zapalnych). Konwersji dokonywano najczęściej w przypadkach utrudnionej oceny struktur anatomicznych trójkąta Calota, wynikającej z miejscowego stanu zapalnego, wysięku przyściennego oraz pogrubienia ściany >5 mm. Pozostałe zmiany występowały rzadziej. Wnioski: Do najczęstszych przyczyn konwersji w badaniach obrazowych należały: zapalny naciek okolicy trójkąta Calota, wysięk przyścienny i pogrubienie ściany > 5 mm. Do cholecystektomii klasycznej w ostrym zapaleniu pęcherzyka żółciowego powinni być kwalifikowani pacjenci, u których w badaniu ultrasonograficznym stwierdza się trzy główne powikłania miejscowe oraz u których występują ostre objawy kliniczne.
EN
The presence of lymph node metastases in esophageal cancer is one of the most principle prognostic indicators.The aim of the study was the assessment of cervical and abdominal lymph nodes (N/pN) by ultrasound (US) examination in patients with squamous cell carcinoma of the thoracic esophagus referred to esophagectomy.Material and methods. The analyzed study population consisted of 110 patients who underwent a combined-modality treatment (neoadjuvant chemotherapy - 74 patients or chemoradiotherapy - 36 patients). The results of US lymph node assessment were compared to the results of histopathological evaluation of lymph nodes harvested during surgery and diagnostic value of cervical and abdominal US in terms of sensitivity, specificity, positive and negative predictive value were determined.Results. The complete metastatic regression was shown by US in 14.3-22.2% of patients depending on the node location and mode of neoadjuwant treatment. There was no significant difference in the assessment of lymph nodes between chemotherapy and chemoradiotherapy patients.Conclusions. US investigation is a method recommended for the assessment of metastatic lymph nodes in squamous cell oesophageal carcinoma, especially - for cervical nodes, where its specificity amounted to 96% and sensitivity - 100%. When positive nodes are suggested by US of the neck esophagectomy should be combined with 3-field lymphadenectomy.
EN
Adenocarcinoma is the most frequent pathology diagnosed in patients with pancreatic mass lesions, and it must be differentiated into benign and inflammatory tumors.The aim of the study was to define the efficacy of ultrasound, computed tomography (US/CT) and fine-needle aspiration biopsy (FNAB) in the assessment of pancreatic mass lesions.Material and methods. The study population comprised 150 consecutive patients with heterogeneous pancreatic mass lesions treated at our department between 1999 and 2004. Imaging examinations with US/CT and FNAB were carried out in all the patients. The final nature of the tumor was established based on histopathology in patients who underwent surgery or based on the follow-up course in patients who were not referred to surgical exploration. The sensitivity and specificity of US/CT and FNAB were calculated by comparing the clinical diagnosis resulting from US/CT interpretation and FNAB results obtained before treatment with the final diagnosis.Results. FNAB appeared to be a safe and relatively simple procedure with no remarkable complications. Malignant tumors were finally diagnosed in 99 (66%), and benign were finally diagnosed tumors in 51 (34%) patients. The sensitivity and specificity were calculated to be 90% and 77.3% for US/CT and 86.9% and 100% for FNAB, respectively.Conclusions. The imaging examination with US/CT is a relatively reliable method for the differential diagnosis of pancreatic mass lesions. A positive FNAB has still remained the most accurate diagnostic method.
EN
The aim of the study was to investigate the impact of Nissen-Rossetti fundoplication on the blood flow in the microcirculation of the gastric fundus.Material and methods. Eight patients undergoing Nissen-Rossetti fundoplication were included in the study. Perfusion in the gastric fundus was measured intraoperatively with laser Doppler flowmetry. An adhesive, flat, silicon probe was attached to the serosa in the same anatomical location during every measurement. Microcirculatory blood flow was recorded before and after fundoplication without ligation and division of the short gastric vessels.Results. In each patient, fundoplication led to increases in resting perfusion. Hyperperfusion was evoked by two mechanisms: increase in average blood flow and increase in vasomotion's amplitude and frequency.Conclusions. Fundoplication constitutes a new distribution of blood flow in the microcirculation of the gastric fundus, irrespective of its indication as a treatment of reflux disease or a supplement to cardiomyotomy in patients with achalasia. The procedure, when correctly performed, leads to local reactive hyperemia. Decreases in fundal perfusion suggest that the fundoplication wrap was created under excessive tension and may lead to dysphagia and local ischemia with consequences on motility of the lower esophagus. Thus, the assessment of change in perfusion of the gastric fundus after fundoplication might be a valuable tool in the routine quality control for appropriate performance of the fundoplication wrap.
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