Comprehensive track-structure based evaluation of DNA damage by light ions from radiotherapy-relevant energies down to stopping.

Track structures and resulting DNA damage in human cells have been simulated for hydrogen, helium, carbon, nitrogen, oxygen and neon ions with 0.25-256 MeV/u energy. The needed ion interaction cross sections have been scaled from those of hydrogen; Barkas scaling formula has been refined, extending its applicability down to about 10 keV/u, and validated against established stopping power data. Linear energy transfer (LET) has been scored from energy deposits in a cell nucleus; for very low-energy ions, it has been defined locally within thin slabs. The simulations show that protons and helium ions induce more DNA damage than heavier ions do at the same LET. With increasing LET, less DNA strand breaks are formed per unit dose, but due to their clustering the yields of double-strand breaks (DSB) increase, up to saturation around 300 keV/µm. Also individual DSB tend to cluster; DSB clusters peak around 500 keV/µm, while DSB multiplicities per cluster steadily increase with LET. Remarkably similar to patterns known from cell survival studies, LET-dependencies with pronounced maxima around 100-200 keV/µm occur on nanometre scale for sites that contain one or more DSB, and on micrometre scale for megabasepair-sized DNA fragments.

The role of lifestyle changing to improve the semen quality in patients with varicocele.

AIM: To evaluate the recovery of semen quality in patients with high grade varicocele without hypotrophy and abnormal semen analysis using a simple lifestyle changing protocol. METHODS: Fifty-two patients were eligible for this study. Two semen sample were collected at baseline and other two after treatment. PROTOCOL: patients had to stop or decrease the number of cigarette per day, reduce the coffee and alcohol consumption, introduce fruits and vegetables in the daily diet and have a normal sexual activity with an abstinence of tree days before semen collection. All the variables and the semen parameters were evaluated and correlated between responders and non-responders. RESULTS: Forty patients (76%) had an improvement of semen quality showing a normal semen analysis following the WHO criteria. The other 12 patients had an improvement of the semen quality but without statistical differences. Smokers and drinkers (for both coffee and alcohol) had lower sperm volume, lower sperm motility and vitality when compared to the others. CONCLUSIONS: The analysis of data collected by the spermiograms showed that semen quality could benefit from lifestyle changing. This finding is important for the management of patients with varicocele, suggesting that lifestyle changing could avoid surgery.

Immunoactivation by pidotimod in children with recurrent respiratory infections.

The therapeutic activity and safety of pidotimod ((R)-3-[(S)-(5-oxo-2-pyrrolidinyl) carbonyl]-thiazolidine-4-carboxylic acid, PGT/1A, CAS 121808-62-6), a new synthetic "biological response modifier", were examined in a double-blind, placebo-controlled, multicentre trial in 101 children, including 53 boys and 48 girls aged 2-13 years (mean +/- SD: 4.7 +/- 2.1 years) with a history of recurrent respiratory infections (RRI). Pidotimod (400 mg/day) or placebo were administered orally for 60 consecutive days, followed by a further 60-day follow-up period. The trial was completed by 89.1% of patients. The results indicate that pidotimod has a beneficial effect in children with recurrent respiratory infections: the percentage of patients presenting symptoms affecting the upper and lower airways was significantly lower after treatment with the active drug than after treatment with placebo. Relevant side effects were not reported during the trial. An evaluation of the expression of CD25 (after in vitro stimulation of circulating mononuclear cells with PHA) before and after treatment with the two products revealed a significant increase in CD25+ cells in the group treated with pidotimod but not in the group treated with placebo.

Modulating effects on CD25 and CD71 antigen expression by lectin-stimulated T lymphocytes in the elderly.

During the last few years, several observations outline that the impaired T lymphocyte proliferative capacity in the elderly is due to a reduced interleukin 2 (IL-2) release. To further investigate the activation process during lectin stimulation, aged peripheral blood mononuclear cells (PBMC) were stimulated with phytohemagglutinin (PHA) and assessed for CD25 (IL-2 receptor) and CD71 (transferrin receptor) expression at different intervals of time. Our results provided evidence for a significant decline of both structure induction, above all in the later phase of culture. Indomethacin (INDO) treatment gave rise to an enhancement of CD71 antigen expression only, while prostaglandin E2 (PGE2) supplementation to culture media further decreased either CD25 or CD71 receptor induction. Interferon (IFN)-alpha and IFN-gamma treatment failed to modulate the frequency of CD25+ and/or CD71+ cells. Finally, the expression of CD71 receptor was increased by deferoxamine supplementation, this suggesting a partial involvement of iron overload in the depressed function. Although further studies are required to evaluate at a molecular level the decreased antigen expression, these findings indicate that several mechanism are involved in the elderly-related decline of T lymphocyte activation structures during lectin stimulation.