Preparation and the kinetic stability of hyaluronan radiolabeled with 111In, 125I and 14C.

Three different procedures for the labeling of hyaluronan (HA) with (111)In, (125)I and (14)C radionuclides were compared, and the kinetic stability of radiolabeled HA under different conditions (saline, artificial gastric juice and plasma) was established. Modification of HA structure with bifunctional chelating agents (DTPA) or with the prosthetic group (tyramine or tyrosine) was essential prior (111)In and (125)I labeling. These chemical labeling techniques were fast, simple and inexpensive, and labeled agents with a high specific activity were obtained. The only disadvantage of these methods was the occurrence of unknown functional groups in the HA molecule requiring further characterization of the compound. Conversely, HA labeling with (14)C by biotechnological synthesis was found to be rather expensive and time-consuming process. Although, the final product (14)C-HA was identical to natural HA its low specific activity presents certain limitation for its application in biological experiments. Stability studies showed that (14)C-HA and (125)I-Tm-HA were stable in all studied mediums. In the case of (125)I-Trs-HA, stability slightly decreased in rat plasma and in artificial gastric juice with increasing time. The least stable was (111)In-DTPA-HA, which degraded completely after 48h in artificial gastric juice. Kinetic stability studies may provide primary information concerning the properties of radiolabeled HA in vitro, which is essential for the use and explanation of its behavior in biological experiments.

[Incidence of pancreatic carcinoma in persons with chronic pancreatitis]. / Incidence pankreatického karcinomu u osob s chronickou pankreatitidou.

INTRODUCTION: Pancreatic carcinoma is one of the diseases which mostly fail to be diagnosed on a timely basis, and there is no way to effectively screen patients for pancreatic carcinoma either. An option for the diagnosis of the "early glandular carcinoma" therefore resides in identification and systematic screening of patients with risk of pancreatic carcinoma. METHOD: We monitored 223 patients with chronic pancreatitis on a systematic basis from 1992 to 2005. During this 14-year period, we monitored the number of cigarettes smoked per year in addition to standard parametres measured by biochemical methods, endosonography, CT and ERCP exams, and assigned the alcoholic form of chronic pancreatitis to patients consuming more than 80g of alcohol per day on a systematic basis for more than 5 years in the case of men, and 50 g of alcohol per day in the case of women, and classed the patients according the TIGARO classification. RESULTS: Alcoholic etiology was proven in 73.1% of the examined patients, chronic obstructive form of pancreatitis was diagnosed in 21.5% of patients, and only 5.4% of patients were classified into the idiopathic pancreatitis group. Pancreatic carcinoma in the region of chronic pancreatitis was found in 13 patients (5.8%); stomach carcinoma was diagnosed in 3 patients with chronic pancreatitis, and oesophageal carcinoma in 1 patient of the total of patients monitored. Malignant pancreatic disease was diagnosed primarily in patients with alcoholic pancreatitis (4.5%). During the period of 14 years, 11 patients died, 8 of the deaths being associated with pancreatic carcinoma. CONCLUSION: Both pancreatic and extrapancreatic carcinoma in gastrointestinal location is a serious complication of protracted chronic, non-hereditary pancreatitis. Systematic identification and treatment of patients with chronic pancreatitis is therefore necessary for timely diagnosis ofgastrointestinal and pancreatic malignancies.