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.

Common contact sensitizers in the Czech Republic. Patch test results in 12,058 patients with suspected contact dermatitis*.

The patch test results of 12 058 patients (4416 male and 7642 female) referred to 9 clinics in the Czech Republic between January 1997 and December 2001 were evaluated. Patients were tested with the same series of allergens by using the standardized patch testing method. The current standard tool for diagnosing allergic contact dermatitis (ACD) in the Czech Republic is the Trolab test panel (Hermal, Reinbeck, Germany) which consists of 23 allergens. Only a few data exists on ACD in the Czech Republic. All patients were tested with the 23 allergen European standard series. Of these patients, 7661 (63.5%) had 1 or more positive reactions. On average, there were 2.8 positive reactions per patient. ACD, according to clinical relevance, was diagnosed in 5339 (69.7%) of these patients. The most frequent allergens were metals (22.9%), especially nickel sulfate (13.8%), and followed by Myroxylon pereirae resin (balsam of Peru) (7.3%), fragrance mix (5.8%), formaldehyde (4.2%) and lanolin alcohol (3.0%). Our results were compared with results from other countries. We conclude that the European standard series is suitable for detection of ACD in the Czech Republic.