Persistence of genetic damage in lymphocytes from former uranium miners.

Lymphocytes from former uranium miners who finished work underground one or more decades ago were analysed with respect to possibly persisting genetic damage induced by their radiation exposure. A modified micronucleus-centromere test was used which determined the frequency of micronucleus-containing binucleate cells after cytochalasin B treatment and the percentage of centromere-free micronuclei, assessed with the help of immunofluorescence labeling of centromere protein B. Whereas the overall frequency of micronucleus-containing cells was not significantly elevated above the level found in a control group, former miners showed a greater percentage of centromere-free micronuclei, i.e. micronuclei containing only acentric fragments. Our results are in excellent agreement with those of an earlier uranium miner study and lend support to the assumption that genetic damage from alpha radiation can persist for many years after exposure, possibly due to genomic instability. The frequency of micronucleus-containing cells, but not the percentage of centromere-free micronuclei, significantly increased with time since last exposure in the mines. This can be attributed, at least in part, to the fact that miners who have finished working underground longer ago tend to be older, and there is an increase of the frequency of micronucleus-containing cells with age.

Clinical trial: endoscopic evaluation of naproxen etemesil, a naproxen prodrug, vs. naproxen - a proof-of-concept, randomized, double-blind, active-comparator study.

BACKGROUND: Nonsteroidal anti-inflammatory drugs are associated with upper gastrointestinal mucosal injury. Naproxen etemesil is a lipophilic, non-acidic, inactive prodrug of naproxen that is hydrolysed to pharmacologically active naproxen once absorbed. We hypothesized that with lesser topical exposure to naproxen from the prodrug, there would be reduced gastroduodenal mucosal injury compared with naproxen. AIM: To compare the degree of endoscopic mucosal damage of naproxen etemesil vs. naproxen. METHODS: This multicentre, randomized, double-blind, double-dummy trial compared oral naproxen etemesil 1200 mg twice daily (n = 61) with naproxen 500 mg twice daily (n = 59) for 7.5 days in 120 healthy subjects (45-70 years; mean 51 years; 58% female) with baseline total modified gastroduodenal Lanza score ≤ 2 (no erosions/ulcers) on endoscopy. The primary endpoint was mean total modified gastroduodenal Lanza score on day 7. A secondary endpoint was incidence of gastric ulcers. RESULTS: The day 7 mean total modified gastroduodenal Lanza score was 2.8 ± 1.7 for naproxen etemesil vs. 3.5 ± 2.0 for naproxen (P = 0.03), and significantly fewer naproxen etemesil-treated subjects (3.3%) developed gastric ulcers compared with naproxen-treated subjects (15.8%) (P = 0.02). CONCLUSION: In this first proof-of-concept study, naproxen etemesil was associated with significantly lower gastroduodenal mucosal injury compared with naproxen after 7 days of exposure ( CLINICAL TRIAL NUMBER: NCT00750243).

Immunocapture RT-PCR probing of potato virus Y isolates.

Twenty potato virus Y (PVY) isolates were characterized. They represented two strains only, PVY(O) (three isolates) and PVY(N) (17 isolates). However, application of serological and molecular genetic methods led to a more complicated characterization. For example, five isolates induced necrotic symptoms on tobacco plants typical of PVY(N), despite reacting as PVY(O) serologically. Moreover, the PVY isolates were not identical according to molecular genetic properties. Typical PVY(NTN) PCR products were observed for 14 isolates, but five of them (Hr 220-5, Hr 387-7, Nord 242, Syn1Scot, and 41-97) did not produce potato tuber necrotic symptoms in infected cultivars. An immunocapture reverse transcription-polymerase chain reaction (RT-PCR) probing was developed using a set of 24 primer pairs derived from eight regions of the PVY genome. Using this method, five out of seven PVY(NTN) isolates including the Czech standard PVY(NTN) from the potato cv. Nicola were found to be identical. However, two PVY(NTN) isolates and all the other probed PVY samples showed unique patterns, suggesting specific differences at the nucleotide level. This method enabled specific identification of individual isolates variability even within different PVY strains.

The alveolar septal thickness and type II pneumocytes number in irradiated lungs, time expression and the effect of pentoxifylline.

PURPOSE: We studied the relationship between type II pneumocytes number and alveolar septal thickness during different time after sublethal whole-thorax irradiation of rats and we investigated the influence of pentoxifylline (TNF-alpha inhibitor). MATERIALS AND METHODS: Wistar rats were exposed to 15 Gy thoracic irradiation and pentoxifylline (35 mg/kg) twice a week. Lungs were examined histologically and immunohistochemically at intervals ranging from 1-12 weeks and alveolar septal thickness, number of type II pneumocytes (identified by immunoreactivity for cytokeratin 18), and neutrophile granulocytes were counted. RESULTS: Significant increase of alveolar septal thickness and type II pneumocytes depletion 3 weeks after irradiation were found. Correlation of these markers was r = -0.759. Pentoxifylline significantly inhibits increased alveolar septal thickness without the influence on type II pneumocytes number. Neutrophil penetration started 5 weeks after irradiation in non-treated animals, 8 weeks after irradiation in PTX-treated rats. CONCLUSIONS: We suggest that pneumocytes depletion is linked to increased vascular permeability, and pentoxifylline therapy does not influence on pneumocytes kinetics after irradiation.

Apoptosis and bcl-2 expression in irradiated lungs and the effect of pentoxifylline.

We measured number of bcl-2, apoptotic, neutrophil, and surfactant apoprotein D (SP-D) positive cells in irradiated rat lungs during different time points after the sublethal whole-thorax irradiation of rats. We also investigated the influence of pentoxifylline (PTX) therapy on these markers. Wistar rats were given 15 Gy thoracic irradiation and PTX (35 mg/kg) twice a week. Animals were examined histologically and imunohistochemically at intervals from 1-12 weeks. In non-treated rats compared with treated rats, bcl-2 expression was significantly inhibited from 4 weeks after irradiation. A higher apoptosis presence in non-treated rats from 4 weeks was found and apoptosis development in PTX-treated animals was delayed and started 8 weeks after irradiation. Similar differences were measured during neutrophil granulocytes examination. Neutrophil penetration in non-treated rats was found 5 weeks after irradiation in contrast to the RP onset of PTX-treated animals 8 weeks after irradiation. The number of SP-D positive cells in non-treated rats observed until 5 weeks after irradiation was higher than in the control group. PTX-treated animals expressed higher number of SP-D positive cells during the whole experiment than the control group. We suggest that apoptosis is linked to neutrophil granulocyte actions during the RP onset and that PTX-therapy causes diminished inflammation development.

Experimental radiation pneumonitis studied with indium-111-pentetreotide.

OBJECTIVES: To understand the evolution of lung uptake of 111-In-Pentetreotide in a rat model of pulmonary radiation pneumonitis. METHODS: A 15 Gy 60-Co thoracic irradiation (1.4 Gy/min) was delivered to Wistar rats. Irradiated and control animals were studied during 8 weeks after irradiation. 24 hours after an injection of 111-In-pentetreotide (12-18 MBq), the uptake in the lung tissue (ULT), in the alveolar cells (UpC) and in different organs, was determined. Histological examinations were performed. RESULTS: ULT and UpC after irradiation increased significantly peaking at 4 weeks (ULT: 32.8 +/- 13.0 in 10(-5) of the injected dose versus 10.8 +/- 2.0 for control; and, UpC was 19.3 +/- 7.2 versus 7.3 +/- 4.1) and decreased afterwards. Pre-injection of cold octreotide decreased the lung uptake. This evolution parallels the histological changes: alveolitis with granulomas in the interstitium at 4 weeks followed by development of sites of interstitial fibrosis. These observations suggest that the uptake is due to activated cells, mainly macrophages within the granulomas and in the alveoli, expressing somatostatin receptors. CONCLUSION: 1) The uptake of 111-In-pentetreotide in injured lungs after irradiation, already described in man, was confirmed in a rat model; 2) our results suggest that it is possible to follow the evolution of radiation lung injury by using In-111-pentetreotide.